WO2025181697A1

WO2025181697A1 - Bifunctional degraders of anti-pla2r antibody

Info

Publication number: WO2025181697A1
Application number: PCT/IB2025/052068
Authority: WO
Inventors: Anna BUNIN; Edward DERAMON; Julie SILVERMAN; Miranda L. SIMES; Prabha SARANGI
Original assignee: Biohaven Therapeutics Ltd
Current assignee: Biohaven Therapeutics Ltd
Priority date: 2024-02-26
Filing date: 2025-02-26
Publication date: 2025-09-04
Anticipated expiration: 2026-08-26

Abstract

A composition of matter including an anti-PLA2R antibody-binding moiety, a cellular receptor-binding moiety which binds to hepatocytes or other degrading cells through asialoglycoprotein receptors (ASGPR) on the surface of hepatocytes or other degrading cells in a patient or subject, and optionally, a linker moiety connecting the anti-PLA2R antibody-binding moiety and the cellular receptor-binding moiety, wherein the composition of matter is useful for removing anti-PLA2R antibody in a patient or subject.

Description

BIFUNCTIONAL DEGRADERS OF ANTI-PLA2R ANTIBODY FIELD OF THE INVENTION [001] The invention generally relates to medicinal preparations characterized by the non-active ingredients used, e.g., carriers or inert additives, targeting or modifying agents chemically bound to the active ingredient, the non-active ingredient being chemically bound to the active ingredient, e.g., polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an antibody, an immunoglobulin or a fragment thereof, e.g., an Fc-fragment the modifying agent being an antibody or an immunoglobulin bearing at least one antigen-binding site the antibody targeting a receptor, a cell surface antigen or a cell surface determinant. Specifically, the invention relates to bifunctional molecules containing a circulating protein-binding moiety that binds to anti-PLA2R antibody for the treatment of membranous nephropathy. BACKGROUND OF THE INVENTION [002] Membranous nephropathy (primary membranous nephropathy, pMN) is an autoimmune disease characterized by the accumulation of immune complexes in the renal glomeruli. Idiopathic membranous nephropathy (IMN) is a glomerular disease, causing fatigue, swelling, and high cholesterol. The current standard of care is an immunosuppressive therapy. High-risk patients receive immunosuppressive therapy. Cyclophosphamide is used in patients with severe decline in kidney function. [003] The phospholipase A2 receptor 1 (PLA2R1) is an autoantigen in membranous nephropathy patients. A mouse model of phospholipase A2 receptor 1-associated membranous nephropathy mimics podocyte injury in patients a transgenic mouse line expressing murine full-length PLA2R1 in podocytes. Meyer-Schwesinger et al., Kidney International, 97(5), 913-919 (2020). [004] No specific therapy exists for Idiopathic membranous nephropathy. About one-third of patients eventually develop kidney failure or end-stage renal disease (ESRD) within five-fifteen years despite standard-of-care immunosuppressive treatment, requiring kidney allograft. Idiopathic membranous nephropathy recurs in 50% of all kidney allograft recipients. [005] There remains a need in the biomedical art for new medicines capable of treating or slowing down progression of idiopathic membranous nephropathy.

1 30124-WO-PCT SUMMARY OF THE INVENTION [006] The invention is directed to bifunctional molecules (agents, TRAPs) capable of binding and degrading anti-PLA2R antibody. In one embodiment, the invention provides an anti-PLA2R autoantibody degrader to treat idiopathic membranous nephropathy. An anti-PLA2R degrader could be a safe and effective treatment for idiopathic membranous nephropathy, with a side effect profile better than the current standard of care. [007] In another embodiment, the invention provides a composition of matter (an agent, a TRAP) comprising: an anti-PLA2R antibody-binding moiety, a cellular receptor-binding moiety that can bind to hepatocytes or other degrading cells through asialoglycoprotein receptors (ASGPR) of hepatocytes or other cell receptors on the surface degrading cells in a patient or subject, and a linker moiety connecting the anti-PLA2R antibody moiety and the cellular receptor-binding moiety, wherein the linker moiety can be a single peptide bond or a larger linker moiety. [008] In some embodiments, the invention provides a composition of matter (an agent, a TRAP) having a structure of: R^CN _{−(Xaa)y−R} ^CC _, ,

2 30124-WO-PCT eof. [009] In some embodiments, the invention provides a composition of matter (an agent, a TRAP) of formula AGN105: the composition of matter has additional elements described in this specification. [010] In more particular embodiments, the invention provides a composition of matter (an agent, a TRAP) selected from the group consisting of the compounds in TABLE 1. TABLE 1 # Characteristics AGN302 31mer (bicyclic)-TBT103 MW 5240.9 Da AGN303 31mer (bicyclic)-TBT104, MW 5240.9 Da. AGN304 31mer (bicyclic)-CF3 pyrazine, MW 4080.61 Da. AGN306 31mer-TBT103, MW 5258.92 Da. AGN307 31mer-TBT104, MW 5258.92 Da. AGN308 31mer-CF3 pyrazine, MW 4098.62 Da AGN309 31mer- PR1, MW 4036.68 Da. AGN310 31mer- GN2 MW 4690.36 AGN362 ABT816-TBT307 AGN363 ABT816-TBT443 AGN364 ABT817 sortase conjugated with TBT544). MW 22436.86 Da. AGN365 ABT819 sortase conjugated with TBT544 MW 44914.95 Da.

3 30124-WO-PCT TABLE 1 # Characteristics AGN579 ABT818 MATE conjugated with TBT307). The product exists as a dimer (Fc). GN3 is conjugated at K248 of each Fc unit. MW 140601 Da. AGN580 ABT818-TBT443 AGN167 ABT740 maleimide conjugated with TBT506. GN3 conjugated to the C-terminal cysteine residue via maleimide conjugation [011] In some embodiments, the anti-PLA2R antibody binding moiety is a peptide selected from secretory phospholipase A2 receptor peptides disclosed by Fresquet et al., J. Am. Soc. Nephrol.26, 302– 313 (2015). See SEQ ID NO: 60-145. See corresponding peptides SEQ ID NO: 636-721 from International Patent Application PCT/IB2025/050867, filed January 26, 2025. [012] In more particular embodiments, the anti-PLA2R antibody-binding moiety selected from the group consisting of the moieties in TABLE 2. TABLE 2 # ABT301, unconjugated 31mer (bicyclic), 3475.05 Da. ABT305. unconjugated (31-mer) WQDKGIFVIQSESLKK(CIQAGKSVLTLENC)K, 3493.11 Da. ABT309, 24mer VIQSESLKK(CIQAGKSVLTLENC)K, 2618.08 Da. ABT310 (SEQ ID NO: 10) [VIQSES], 661.702 Da. ABT311 (SEQ ID NO: 11) [SVLTLENCK], 1006.175 Da. ABT312, 31mer (biotinylated), 4094.87 Da. ABT407 (SEQ ID NO: 146). CysR-CTLD1, GGGGS-His6-GGGGS-Cys. ABT408 (SEQ ID NO: 147). CysR-CTLD1, GGGGS-His6-Cys. Number of amino acids: 359, Molecular weight: 41072.01 Da, Theoretical pI: 5.76. ABT409 (SEQ ID NO: 148). CysR-CTLD1, GGGGS-His6-GGGE-Cys-S, Number of amino acids: 364, Molecular weight: 41459.36 Da, Theoretical pI: 5.70. ABT427 (FnII-CTLD1-his) ABT530 (SEQ ID NO: 14), heavy chain sequence for hIgG1 LALA/PA sequence. ABT603, SEQ ID NO: 19. Light chain, Molecular weight: 22904.35Da, Theoretical pI: 4.72 ABT606, Abcam anti-rabbit PLA2R mAb, combined Light chain + Heavy chain ABT816 (SEQ ID NO: 15). CysR domain + GGGGS linker, hIgG1 Fc (CàA)-LALA/PA. Number of amino acids: 389, Molecular weight: 43224.10 Da, Theoretical pI: 8.91.

4 30124-WO-PCT TABLE 2 # ABT817 (SEQ ID NO: 16). CysR_Sortase, GGGGS linker, Sortase site, His6 tag. Number of amino acids: 169, Molecular weight: 18669.24 Da, Theoretical pI: 9.46. N-glycoform is present. ABT818 (SEQ ID NO: 17). CysR-CTLD1_Fc-fusion, GGGGS linker, hIgG1 Fc (CàA)-LALA/PA. Number of amino acids: 584, Molecular weight: 66078.34 Da, Theoretical pI: 6.23.2 N-glycoforms are present on each chain. ABT819 (SEQ ID NO: 18). CysR-CTLD1 + Sortase, GGGGS linker, sortase site, His6 tag. Number of amino acids: 364, Molecular weight: 41523.47 Da, Theoretical pI: 6.33. N-glycoform is present. ABT976, CysR-CTLD1 no tag. CysR-CTLD1 (21-367) + Thrombin recognition sequence + His10 tag, Before thrombin cleavage: Number of amino acids: 363, Molecular weight: 41811.88 Da, Theoretical pI: 5.95. After thrombin cleavage: Number of amino acids: 351, Molecular weight: 40296.34 Da, Theoretical pI: 5.55. ABT983 (final mAb product with ABT603, SEQ ID NO: 19 + ABT982, SEQ ID NO: 20) ABT985 (final mAb product with ABT603, SEQ ID NO: 19 + ABT984, SEQ ID NO: 21) [013] In another embodiment, the cellular receptor-binding moiety comprises an ASGPR-binding group according to the chemical structure: wherein the cellular receptor-binding moiety has additional elements described in this specification.

5 30124-WO-PCT [014] In some specific and nonlimiting embodiments, the cellular receptor-binding moiety is selected from the group in TABLE 3. TABLE 3 ID NO. Chemical Structure TBT103 TBT104 NH O_OH O O OH O_O O H_N OH O N H_O H O O HO O O O O N H O O HO H O O NH H _N ^N H O H N O O N N N N HO O O N O H H O O N N O HO O _O H H^N N H O O O H_O ^O HN TBT105

6 30124-WO-PCT TABLE 3 ID NO. Chemical Structure TBT307 TBT544

7 30124-WO-PCT TABLE 3 ID NO. Chemical Structure TBT506 _{HO OH} OH HN O O O O O NH O O O O O H O O O N N O N O OH N O H O_O H HN OH NH OH O O O O OH O O OH O NH OH [015] In another embodiment, the invention provides the composition of matter (agent, TRAP) for use as a medicine. [016] In another embodiment, the invention provides the composition of matter (agent), TRAP for use in treating or preventing a disease state or condition associated with the presence of anti-PLA2R autoantibody in a subject or patient. [017] In another embodiment, the invention provides the composition of matter (agent, TRAP) for use in treating a disease membranous nephropathy. [018] In another embodiment, the invention provides a pharmaceutical composition including the composition of matter and at least one pharmaceutically acceptable excipient. [019] In another embodiment, the invention provides a method of making a composition of matter wherein the method comprises a conjugation step, wherein the conjugation step results in an anti-PLA2R antibody-binding moiety being linked to a cellular receptor-binding moiety. In another embodiment, the method of making the composition of matter comprises a conjugation step selected

8 30124-WO-PCT from the Markush group comprising a MATE conjugation step, a maleimide conjugation step, and a sortase conjugation step. [020] In another embodiment, the invention provides a method of making a molecule wherein the anti-PLA2R antibody-binding moiety is linked to another molecule or a device, wherein the method comprises a conjugation step selected from the Markush group comprising a MATE conjugation step, a maleimide conjugation step, a sortase conjugation step, and an AviTag™ conjugation step. [021] In another embodiment, the invention provides a method of removing anti-PLA2R antibody in a patient or subject in need thereof by administering a composition of matter described herein to the patient or subject. [022] In another embodiment, the invention provides a method of treating or condition associated with the upregulation of anti-PLA2R autoantibody in a patient or subject in need by administering to the patient or subject an effective amount of a composition of matter described herein. [023] In another embodiment, the invention provides a composition including a composition of matter described herein and at least one additional molecule comprising a moiety capable of binding to an anti-PLA2R antibody that forms the antibody moiety of the first compound. [024] Several objects, features, aspects, and advantages of the invention will become more apparent from the following detailed description of embodiments of the invention, along with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS [025] For illustration, some embodiments of the invention are shown in the drawings described below. Like numerals in the drawings indicate like elements throughout. The invention is not limited to the precise arrangements, dimensions, and instruments shown. [026] FIG.1 is a chemical drawing showing that azidohomoalanine can be incorporated into a synthetic 31-mer to help with click to ASGPR ligand. CryoEM and epitope mapping of PLA2R have shown that the 31-mer peptide mimics key epitope CysR region. FIG.1 highlights key amino acids in the binding: V, I, and E. Two key antigenic regions, SVLTLENCK (ABT311, SEQ ID NO: 11) and VIQSES (ABT310; SEQ ID NO: 10) were determined by peptide microarray. See Fresquet, Lockhart-Cairns, Rhoden, & Lennon, Proc. Natl. Acad. Sci, U.S.A., 119 (29), e2202209119) (July 11, 2022). The linker attachment unlikely to interfere with antibody-binding. [027] FIG.2 is TABLE 4, showing R-Groups for MATE reagents and bifunctional MoDE final compounds.

9 30124-WO-PCT [028] FIG.3 is a flow chart showing the decision-making for the prior art standard-of-care treatment for idiopathic membranous nephropathy. One-third of patients experience spontaneous remission. According to the KDIGO guidelines, “Changes in anti-PLA2R antibodies levels during follow-up likely add to risk estimation. Disappearance of anti-PLA2R antibodies precedes clinical remission.” [029] FIG.4 shows the structure of several anti-PLA2R-degrader compounds. [030] FIG.5 shows a visual representation of anti-PLA2R degrader conjugation methods. [031] FIG.6 shows a visual representation of PLA2R degraders-sortase conjugated. [032] FIG.7 shows a visual representation of PLA2R degraders-maleimide conjugated. [033] FIG.8 shows a visual representation of PLA2R degraders- MATE conjugated. [034] FIG.9 is a chart showing anti-PLA2R binding in ischemic monomelic neuropathy (IMN) samples with AFN364 and AGN365. Anti-PLA2R degraders AGN364 and AGN365 captured the majority of anti-PLA2R antibodies from IMN patient samples via competitive EuroImmun clinical anti-PLA2R ELISA. Most samples brought below diagnostic cut-off for anti-PLA2R positivity (14 RU/ml). DETAILED DESCRIPTION OF THE INVENTION [035] The following detailed description is provided to aid persons having ordinary skill in the biomedical art. Exemplary embodiments are described. However, these embodiments are only exemplary. This disclosure is not limited thereto but is defined by the scope of the appended claims. Persons having ordinary skill in the biomedical art may make modifications and variations in the embodiments described in this specification without departing from the spirit or scope of this disclosure. Industrial Applicability [036] The invention provides a medically useful composition of matter (agent, TRAP) for the treating or slowing down progression of diseases that are manifestations of anti-PLA2R antibody disfunction, such as membranous nephropathy. [037] The Kidney Disease Improving Global Outcome (KDIGO) organization issues guidelines for treatment for physicians. KDIGO recommends using anti-PLA2R titers for treatment guidance. Eighty % of idiopathic membranous nephropathy patients have anti-PLA2R antibodies. High anti-PLA2R titers are associated with poor prognosis, worsened disease, and lower chance of spontaneous remission. Depletion of anti-PLA2R by immunosuppressive therapy is predictive of disease remission. See KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases. Kidney international, Vol.

10 30124-WO-PCT 100, Issue 45, Supplement (October 2021). Changes in anti-PLA2R antibodies levels during follow-up can help risk estimation and patient stratification. Persistent anti-PLA2R titers is predictive of poor outcome. [038] About 80% of idiopathic membranous nephropathy patients are anti-PLA2R antibody- positive. Despite treatment, titers persist in 30-40% of patients. These patients typically develop end- stage renal disease and require kidney transplant. Idiopathic membranous nephropathy recurs in 50% of allograft recipients. [039] Chronic membranous nephropathy can cause significant proteinuria and nephrotic syndrome and can progress to kidney failure and nephrotic kidneys in severe cases. Autoantibodies bind to phospholipase A2 receptor (PLA2R) on podocytes in the Bowman’s capsule, injuring glomerular basement membranes. Subepithelial immune complex deposits leads to podocyte injury and thickening of basement membrane, which leads further to proteinuria and hyperlipidemia, resulting in kidney failure. Patients rendered anti-PLA2r negative by immunosuppression have greater disease remission. Lu et al., Medicine (Baltimore), 98(18), e15303 (May 2019). [040] The standard of care is supportive care includes rituximab, cyclophosphamide, calcineurin INH, glucocorticoids, B-cell therapies, and anticoagulants, as well as therapies that address non- autoantibody-targeted systems including the renin-angiotensin-aldosterone system (RAAS), angiotensin- converting enzyme (ACE), angiotensin receptors, and sodium-glucose cotransporter 2 (SGLT2). Rituximab or cyclophosphamide + glucocorticoids are first-line therapies but have undesirable side effects. Combination of plasmapheresis with standard of care shows more favorable outcomes. See Rovin et al. KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases. Kidney Int (2021) 100(4, Supplement):S1–276, and Bennani et al., J. Pers. Med., 14(3), 249 (2024). [041] The inventors conceived of an anti-PLA2R degrader that is a safe and effective treatment to address this unmet need. Disease modifying therapies that stop progression to end-stage renal disease. PLA2R antigen-specific MoDEs rapidly remove pathogenic autoantibodies. Deep reductions in anti- PLA2R autoantibodies will prevent further glomerular injury.

11 30124-WO-PCT Definitions [0035] For convenience, the meaning of some terms and phrases used in the specification, examples, and appended claims, are listed below. Unless stated otherwise or implicit from context, these terms and phrases shall have the meanings below. These definitions aid in describing embodiments but are not intended to limit the claimed invention. [0036] As used in this application, except as otherwise provided in this specification, each term shall have the meaning set forth below. Additional definitions are set forth throughout the application. Where a term is not specifically defined in this specification, that term is given a biomedical art- recognized meaning applying that term in context to its use in describing the invention. [0037] The articles "a" and "an" have the plain meaning of one or to more than one, i.e., at least one, of the grammatical object of the article unless the context indicates otherwise. For example, "an element" means one element or more than one element. [0038] The term “ABT” has the biomedical art-recognized meaning of a binding moiety that is itself an antibody, an antibody variant, or an -binding fragment thereof. In some embodiments, the ABT binds to anti-PLA2R antibody. [0039] The term “active Ingredient” has the United States Food & Drug Administration-provided meaning of any component that provides pharmacological activity or other direct effect in the diagnosis, cure, mitigation, treatment, or prevention of disease, or to affect the structure or any function of a human body or an animal body. [0042] The term “ADCC” has the biomedical art-recognized meaning of antibody-dependent cell- mediated cytotoxicity, is a mechanism of cell-mediated immune defense whereby an effector cell of the immune system kills a target cell, whose membrane-surface antigens have been bound by specific antibodies. [0043] The term “ADCP” has the biomedical art-recognized meaning of antibody-dependent cell- mediated phagocytosis, an immunological mechanism of elimination whereby tumor cells are targeted with antibodies to promote their clearance from the body by phagocytic immune cells. [0040] The term “AF488” has the biomedical art-recognized meaning of Alexa Fluor 488, a bright, green-fluorescent dye with excitation suited for the 488 nm laser line and is used for imaging and flow cytometry. [0041] The term “AF647” has the biomedical art-recognized meaning of the far-red dye Alexa Fluor 647, which has an excitation peak at 650 nm and an emission peak at 665 nm. Alexa 647 is useful for flow cytometry, microscopy, and super-resolution microscopy.

12 30124-WO-PCT [0044] The term “agent” has the biomedical art-recognized meaning of a composition of matter useful for performing a function. Several useful biomedically functions are described in this specification. [0045] The term “alleviate” has the biomedical art-recognized meaning of a process by which the severity of a sign or symptom of a disorder is reduced. A sign or symptom can be alleviated without being eliminated. The administration of compositions or pharmaceutical compositions of the invention may or can lead to the elimination of a sign or symptom, however, elimination is not required. Effective dosages should be expected to decrease the severity of a sign or symptom. [0046] The term “an effective amount” and the term “a therapeutically effective amount” has the biomedical art-recognized meaning of an amount effective to achieve its intended purpose. The effect can be detected by any assay method known in the art. The precise effective amount for a subject will depend on the subject's body weight, size, and health; the nature and extent of the condition; and the therapeutic or combination of therapeutics selected for administration. Therapeutically effective amounts for a situation can be determined by routine experimentation that is within the skill and judgment of the clinician. In embodiments, the disease or condition to be treated is tendinopathy. [0047] The term “anti-PLA2R antibody-binding moiety” has the biomedical art-recognized meaning a moiety on a binding protein, e.g., an antibody, an antibody variant, or an -binding fragment thereof, that binds to an anti-PLA2R antibody. [0042] The term “anti-PLA2R antibody” has the biomedical art-recognized meaning. Anti-PLA2R antibodies can be used for the diagnosis idiopathic membranous nephropathy without a kidney biopsy. Anti-PLA2R antibodies are found in ~80% of idiopathic membranous nephropathy patients. Clinically approved anti-PLA2R tests are commercially available. See, e.g., Mayo Clinic Laboratories Test ID: PLA2M ELISA assay, CPT code information: 83520. Anti-PLA2R antibodies are commercially available. A commercial monoclonal antibody from Abcam Limited specific for the PLA2R epitope being planned for the anti-PLA2R degrader program [fragment corresponding to Human PLA2R aa 1-700]: Mouse monoclonal anti-PLA2R antibody [12-6-5] (ab211490). [0048] The term “antigen-binding fragment thereof” has the biomedical art-recognized meaning of (1) a fragment of an intact antibody that binds to the same antigen recognized by the full-length antibody, such as F(abʹ)₂, F(ab)₂, Fabʹ, Fab, Fv, sFv, or other fragments including the variable regions, or (2) any synthetic or genetically engineered protein that acts like an antibody by binding to a specific antigen to form a complex. The term antigen-binding portion of an antibody encompasses single chain antibodies.

13 30124-WO-PCT [0049] The term “asialoglycoprotein receptor (ASGPR) binding group” has the biomedical art- recognized meaning of a binding group which binds to a hepatocyte asialoglycoprotein receptor. The ASGPR-binding group selectively binds to hepatocyte asialoglycoprotein receptor on the surface of hepatocytes. In several embodiments, an ASGPR-binding group is a component of a bifunctional agent as a cellular receptor-binding moiety which is covalently bound to the antibody-binding moiety through a linker group or directly. It is through this ASGPR moiety that bifunctional agents complexed with a circulating protein, e.g., anti-PLA2R antibody, bind to hepatocytes. After the bifunctional agent complexed with a circulating protein is bound to a hepatocyte or other cell, the circulating protein is taken into the hepatocyte or other cell via a phagocytosis mechanism, wherein the circulating protein is degraded through lysosomal degradation. [0050] The term “asialoglycoprotein receptor (ASGPR) has the biomedical art-recognized meaning of lectins which bind asialoglycoprotein and glycoproteins from which a sialic acid has been removed to expose galactose residues. These cellular receptors are located on mammalian hepatocytes and other cells, such as glandular cells of the gallbladder and the stomach. ASGPR remove target glycoproteins from circulation. [0051] The term "at least one of," when preceding a list of elements, modifies the entire list of elements and does not modify the individual elements of the list. [0052] The term “AT” has the biomedical art-recognized meaning of an antibody moiety. In some embodiments, the AT binds to anti-PLA2R antibody. [0053] The term “cellular receptor-binding moiety” has the biomedical art-recognized meaning. In several embodiments, the cellular receptor-binding moiety is an asialoglycoprotein receptor (ASGPR) binding group. [0054] The term “cellular receptor” has the biomedical art-recognized meaning of a protein on the surface of a cell that binds to a compound, e.g., a ligand, e.g., a protein, in solution or on another cell. Generally, ligand-receptor binding induces one or more biological responses. In this specification, an asialoglycoprotein receptor (ASGPR) is a cellular receptor on the surface of hepatocytes or other cells that binds to an asialoglycoprotein or a derivative thereof. [0055] The term “chimerized” has the biomedical art-recognized meaning. Chimeric antibodies are made by fusing variable domains from one species, such as a mouse, with constant domains from another species, such as a human being. With such biotechnical manipulation, chimeric antibodies keep the foreign antibody’s antigen specificity and affinity.

14 30124-WO-PCT [0056] The term “combination therapy” and the “co-therapy” has the biomedical art-recognized meaning of the administration of a composition described in this specification and at least a second agent as part of a specific treatment regimen intended to provide the beneficial effect from the co- action of these therapeutic agents. The beneficial effect of the combination may include, but is not limited to, pharmacokinetic or pharmacodynamic co-action resulting from therapeutic agents. Administration of these therapeutic agents in combination typically is carried out over a defined time, usually minutes, hours, days, or weeks depending on the combination selected. The term combination therapy” includes the administration of the therapeutic agents as described above in further combination with other biologically active ingredients and non-drug therapies, e.g., surgery or radiation treatment. Where the combination therapy further comprises a non-drug treatment, the non-drug treatment may be conducted at any suitable time if a beneficial effect from the co-action of the therapeutic agents a is achieved. For example, in appropriate cases, the beneficial effect is still achieved when the non-drug treatment is temporally removed from the administration of the therapeutic agents, perhaps by days or even weeks. [0057] The term “complementarity determining region (CDR)” has the biomedical art-recognized meaning of a polypeptide region of an antibody heavy chin or an antibody light chain that is a determinant of the antibody to antigen-binding. Each antibody heavy chain has three CDRs. Each antibody light chain has three CDRs, usually different from the three CDRs on an antibody heavy chain. persons having ordinary skill in the biomedical art calculate the using a standardized numbering method known as the Kabat numbering scheme. Kabat et al, (1991) Sequences of Proteins of Immunological Interest, 5th Ed Public Health Service, National Institutes of Health, Bethesda, MD., USA), although other numbering schemes such as Chothia and IMGT are also used by persons having ordinary skill in the biomedical art. [0058] The term "comprises," the term "comprising," the term "includes," and the term "including" specify stated features, regions, integers, steps, operations, elements, or components, but do not prevent the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, or groups thereof. [0059] The term “Fc-III-4c” has the biomedical art-recognized meaning of a polypeptide region in the fragment crystallizable region (Fc region), the tail region, of an antibody. [0060] The term “Fc-M” has the biomedical art-recognized meaning of a polypeptide region in the fragment crystallizable region (Fc region), the tail region, of an antibody.

15 30124-WO-PCT [0061] The term “FcB-1” has the biomedical art-recognized meaning of a polypeptide region in the fragment crystallizable region (Fc region), the tail region, of an antibody. [0062] The term “FcB-2” has the biomedical art-recognized meaning of a polypeptide region in the fragment crystallizable region (Fc region), the tail region, of an antibody. [0063] The term “first,” “second,” “third,” etc. have the plain meaning of describing several elements, components, regions, layers, or sections, these elements, components, regions, layers, or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. A first element, component, region, layer, or section could be called a second element, component, region, layer, or section without departing from the teachings of the present embodiments. [0064] The term “hepatocyte” has the biomedical art-recognized meaning of a cell of the main parenchymal tissue of the liver. Hepatocytes make up 55-65% of the liver's mass. [0065] The term “humanized” has the biomedical art-recognized meaning a protein, e.g., an antibody, is genetically engineered so it closely resembles the polypeptide structure of the human homologue. A variable domain of an antibody of rodent origin can be fused to a constant domain of human origin, keeping the specificity of the rodent antibody. The human origin domain need not originate directly from a human in that it is first synthesized in a human. Instead, human domains can be generated in rodents whose genome incorporates human immunoglobulin genes. The antibody can be partially humanized. In one approach, there are four general steps used to humanize a monoclonal antibody, These are (1) determining the nucleotide and predicted amino acid sequence of the starting antibody light and heavy variable domains; (2) designing the humanized antibody, i.e., deciding which antibody framework region to use during the humanizing process; (3) the actual humanizing methodologies/techniques; and (4) the transfection and expression of the humanized antibody. [0066] The term “IC₅₀“ has the biomedical art-recognized meaning of an amount, concentration, or dosage of a particular test compound that achieves a 50% inhibition of a maximal response in an assay that measures such response. [0067] The term “idiopathic membranous nephropathy (IMN)” has the biomedical art-recognized meaning. Idiopathic membranous nephropathy is caused by autoimmunity to podocytes. Disease severity is characterized by proteinuria, decrease in glomerular filtration rate (eGFR), and anti-PLA2R antibody titers. M-type phospholipase A2 receptor (PLA2R) is the most often targeted antigen, with antibodies being present in about 80% of idiopathic membranous nephropathy patients. Idiopathic

16 30124-WO-PCT membranous nephropathy is driven by autoimmunity to podocytes, causing increased thickness of the glomerular membrane and changes in podocyte morphology. [0068] The term “IgG” antibody has the biomedical art-recognized meaning. Each IgG molecule includes the basic four-chain immunoglobulin structure—two γ (gamma) heavy chains and two identical light chains (either kappa or lambda)—and carries two identical antigen-binding sites. There are four subclasses of IgG, each with minor differences in its H chains but with distinct biological properties. [0069] The term “IgG1” antibody has the biomedical art-recognized meaning of an IgG antibody where the Ig gamma-1 chain C region is a protein that in humans is encoded by the IGHG1 gene. [0070] The term “IgG2” antibody has the biomedical art-recognized meaning of an IgG antibody where the Ig gamma-2 chain C region is a protein that in humans is encoded by the IGHG2 gene. [0071] The term “IgG4” antibody has the biomedical art-recognized meaning of an IgG antibody where the Ig gamma-4 chain C region is a protein that in humans is encoded by the IGHG4 gene. IgG4 has little effector function. IgG4 cannot fix complement. [0072] The term “IVIG” has the biomedical art-recognized meaning of the administration of intravenous immunoglobulin (IVIG). [0042] The term “K_D” has the biomedical art-recognized meaning of the measured equilibrium dissociation constant between a compound or ligand and a protein or binding domain of a protein. [0043] The term “lipoprotein-associated phospholipase A2” has the biomedical art-recognized meaning. See Blackie et al., Bioorg. Med. Chem. Lett., 13(6), 1067-70 (March 24, 2003). The phospholipase A2 receptor 1 (PLA2R1) is the major autoantigen in patients suffering from membranous nephropathy. Meyer-Schwesinger et al., Kidney International, 97 (5), 913-919 (2020). [0044] The term “linker moiety” has the biomedical art-recognized meaning of a moiety of a chemical compound that links one moiety of the chemical compound to another moiety of the same compound. In several embodiments of this invention, the linker moiety connects an anti-anti-PLA2R antibody IgG antibody moiety to a cellular receptor-binding moiety. [0045] The term “MoDE” has the proprietary meaning of molecular degraders. See International Pat. Publ. WO 2019/199634 (Yale University) and WO 2019/199621 (Yale University). [0046] The term “membranous neuropathy” (primary membranous nephropathy, pMN) has the biomedical art-recognized meaning of an autoimmune disease characterized by the accumulation of immune complexes in the renal glomeruli. It is the most common cause of nephrotic syndrome in adults. [0047] The term “moiety” has the biomedical meaning of a defined chemical group or entity with a particular structure or activity. A moiety generally refers to a part of a molecule, e.g., in an ester

17 30124-WO-PCT RCOOR’, the alcohol moiety is RO−. In some embodiments, a moiety of an agent keeps one or more or all desirable structural features, properties, functions, or activities of a compound. In some embodiments, a cellular receptor-binding moiety can bind to a target, optionally in a comparable fashion, as its corresponding target-binding agent. In some embodiments, a moiety is monovalent. In some embodiments, a moiety is bivalent. In some embodiments, a moiety is polyvalent. [0048] The term “monotherapy” has the biomedical art-recognized meaning of the administration of a single active or therapeutic compound to a subject in need thereof. Monotherapy usually is the administration of a therapeutically effective amount of an active composition. [0049] The term “Multimodal Antibody Therapy Enhancers (MATE or MATES)” has the proprietary meaning. See International Pat. Publ. WO 2021/102052 (Kleo Pharmaceuticals). [0043] The term “nanobody” has the biomedical art-recognized meaning. the term “antibody” refers to immunoglobulin molecules and immunologically active parts of immunoglobulin molecules, i.e., molecules that have an antigen-binding site that specifically binds an antigen. The term also refers to antibodies comprised of two immunoglobulin heavy chains and two immunoglobulin light chains and many forms including full length antibodies and antigen-binding parts thereof; including an immunoglobulin molecule, a monoclonal antibody, a chimeric antibody, a CDR-grafted antibody, a humanized antibody, a Fab, a Fabʹ, a F(abʹ)2, a Fv, a disulfide linked Fv, a scFv, a single domain antibody (dAb), a diabody, a nanobody, a multi-specific (e.g., tri-specific) antibody, a dual specific antibody, a bispecific antibody, an anti-idiotypic antibody, a functionally active epitope-binding part thereof, or bifunctional hybrid antibodies. [0050] The term "on" has the plain meaning. When an element is called being on another element, it can be directly in contact with the other element or intervening elements may be present therebetween. When an element is called being "directly on" another element, there are no intervening elements present. [0051] The term "or" as used in this specification means "or." The term "or" as used in this specification includes all combinations of one or more of the associated listed items. [0052] The term “other degrading cells” has the biomedical art-recognized meaning. Asialoglycoprotein receptors (ASGPRs) are on the glandular cells of the gallbladder and the stomach. [0053] The term “partially humanized” has the biomedical art-recognized meaning a protein, e.g., an antibody, is genetically engineered so it more closely resembles the polypeptide structure of the human homologue. A variable domain of an antibody of rodent origin can be fused to a constant domain of human origin, keeping the specificity of the rodent antibody. The domain of human origin need not

18 30124-WO-PCT originate directly from a human in that it is first synthesized in a human. Instead, human domains can be generated in rodents whose genome incorporates human immunoglobulin genes. The antibody can be partially humanized. [0054] The term “pharmaceutically acceptable excipient” has the biomedical art-recognized meaning of an excipient that is useful in preparing a pharmaceutical composition that is generally safe, non-toxic, and neither biologically nor otherwise undesirable, and includes excipient that is acceptable for veterinary use and human pharmaceutical use. A “pharmaceutically acceptable excipient” as used in the specification and claims includes both one and more than one such excipient. A thorough discussion of pharmaceutically acceptable excipients is available in Remington’s, Pharmaceutical Sciences 23rd edition (Elsevier, 2020). [0055] The term “pharmaceutically acceptable” has the biomedical art-recognized meaning of those compounds, anions, cations, materials, compositions, carriers, or dosage forms which are, within the scope of sound medical judgment, suitable for contact with the tissues of humans and animals without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio. [0056] The term “protein-binding moiety” has the biomedical art-recognized meaning of a region of a chemical composition, e.g., a polypeptide region of a chemical composition, that specifically binds to a protein, e.g., a specific protein. [0057] The term “ROC” has the biomedical art-recognized meaning of receiver operating typical curve. [0058] The term “subject” and the term “patient” have the biomedical art-recognized meanings. The term patient includes human and other mammalian subjects that receive either prophylactic or therapeutic treatment. [0059] The term “TBT” has the biomedical art-recognized meaning of a target-binding moiety, a cellular receptor-binding moiety. In some embodiments, the TBT binds to ASGPR. [0060] The term “treating” and the “treat” has the biomedical art-recognized meaning of the management and care of a patient for combating a disease, condition, or disorder and includes the administration of a composition described in this specification to alleviate the symptoms or complications of a disease, condition, or disorder, or to eliminate the disease, condition, or disorder. [0061] The term “universal antibody-binding moiety” has the biomedical art-recognized meaning of a polypeptide region of an antibody-binding protein that binds a class of antibodies, rather than a specific set of antibodies.

19 30124-WO-PCT [0062] The term “VHH” has the biomedical art-recognized meaning. VHH has 9 beta-sheets forming a cylindric structure. Several regions may bind. The most important regions 4>1, 2 (greatest difference in uptake). The least important: regions 3, 5 (very minor difference in uptake). [0063] Some embodiments are described below by referring to structures and schemes, to explain parts of the description. [0064] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by persons having ordinary skill in the biomedical art. [0065] This specification does not concern a process for cloning humans, methods for changing the germ line genetic identity of humans, uses of human embryos for industrial or commercial purposes, or procedures for changing the genetic identity of animals likely to cause them suffering with no substantial medical benefit to humans or animals resulting from such processes. Methods of selecting subjects for administration of a composition of matter. [042] The presence of anti-PLA2R antibodies can diagnose idiopathic membranous nephropathy without a kidney biopsy. Anti-PLA2R antibodies are highly specific to idiopathic membranous nephropathy (~100%) and found in ~80% of patients. [043] The synthetic 31-mer peptide recognizes the majority of anti-PLA2R antibodies in idiopathic membranous nephropathy patients. The 31-mer peptide can be used in assays to detect anti-PLA2R antibodies in idiopathic membranous nephropathy patients. [044] Laboratory testing for autoimmune disease uses well validated assays to establish the presence of autoantibodies. For membranous nephropathy, autoantibodies to the M-type phospholipase A2 receptor 1 (PLA2R) were first described in 2009. Beck et al., N. Engl. J. Med.361, 11– 21 (2009). The use of serological testing extends beyond diagnosis to encompass prognosis and assessment of disease activity and treatment response. Quantitative assessment of autoantibody production can provide a biomarker for clinical decision-making, as shown by the antibody response to PLA2R in membranous nephropathy. van de Logt et al., Kidney Int.93, 1016–1017 (2018); and Wu et al., Medicine 97, e11018 (2018). Methods of measuring the removal of anti-PLA2R antibody from a patient or subject. [0066] Clinically approved anti-PLA2R tests are commercially available. See, e.g., Mayo Clinic Laboratories Test ID: PLA2M ELISA assay, CPT code information: 83520.

20 30124-WO-PCT Methods of treatment by administering composition of matter. [0067] The ideal mode of administration depends on where treatment is taking place, whether a hospital or outpatient. [0068] In untreated patients with active disease, the previously recommended first-line agent for induction of remission is glucocorticoids, e.g., prednisolone 30–40 mg per day for 2–4 weeks, then gradually tapered over 3 to 6 months, unless contraindications exist. Glucocorticoids characteristically result in a rapid improvement in clinical features and often a resolution of radiographic features. However, where advanced fibrotic lesions have resulted in irreversible damage, the response to glucocorticoids and other current treatment options may be poor or even absent. TABLE 5 Target product profile for a bifunctional degrader of anti-PLA2R in idiopathic membranous nephropathy. Short-term profile Long-term profile Objectives Improvement in kidney function Complete remission of disease, and improved side effect profile including in non-responsive patients. Improved side effect profile Mechanism of action Clearance of anti-PLA2R to reduce immune complex formation in glomerular membrane/podocytes Indication/Patient Idiopathic membranous Idiopathic membranous population nephropathy nephropathy Route of administration/ Intravenous or subcutaneous, Subcutaneous, twice-a-week Dosing regimen once-a-week Clinical efficacy profile Equivalent to standard of care in Superior to standard of care in primary outcome measures. primary outcome measures and Reduction in anti-PLA2R titer. effective in non-responsive Reduction in proteinuria. patients. Anti-PLA2R below LOD. Improvement in eGFR Proteinuria <3.5 g/d. Normal eGFR Safety & tolerability Improved side effect profile relative to standard of care. Well tolerated profile for chronic treatment. [045] Idiopathic membranous nephropathy patients are to be stratified after immunosuppressive treatment.80% of idiopathic membranous nephropathy patients are anti-PLA2R+, and despite treatment, titers persist in 30-40% of patients. These patients typically develop end-stage renal disease (ESRD) and require kidney transplant. Idiopathic membranous nephropathy recurs in 50% of allograft

21 30124-WO-PCT recipients. The efficacy of immunosuppressive therapy can be predicted by its effect on anti-PLA2R titers. [046] Reduction of anti-PLA2R levels is followed by partial or complete remission in most patients. Conversely, persistent anti-PLA2R levels are associated with no remission and poor outcome. Faster depletion in anti-PLA2R levels in patients is also associated with earlier reduction in proteinuria and improved nephroprotection. [047] After the bifunctional degrader of the invention and the bound anti-PLA2R antibody are endocytosed, they are released from the ASGPR through depletion of calcium from the endosome and changes in binding site amino acid protonation changes due to a decrease in pH. The ASGPR is recycled back to the hepatocyte surface. Endocytosed proteins are trafficked to late endosomes, which are fused with lysosomes. Lysosomal proteases then degrade endocytosed proteins, permanently removing them from circulation. The chemical structure of the composition of matter (agent, TRAP). [0069] In an embodiment, the invention composes matter (agent, TRAP) comprising: an anti-PLA2R antibody-binding moiety, a cellular receptor-binding moiety which binds to hepatocytes or other degrading cells through asialoglycoprotein receptors (ASGPR) of hepatocytes or other cell receptors on the surface degrading cells in a patient or subject, and a linker moiety linking the antibody moiety and the cellular receptor-binding moiety. [0070] In some embodiments, the invention composes matter (an agent, a TRAP) having a structure selected from the Markush group of structures including: R^CN−(Xaa)y−R^CC, ,

22 30124-WO-PCT of. In these structures, a, b, and c may independently be an integer of 1 or greater. In some embodiments, each cellular receptor-binding moiety independently has the structure of −(R^CN−(Xaa)y−R^CC) or salt form thereof. [0071] In some embodiments, the invention composes matter (an agent, a TRAP) of formula AGN105: each Xaa is independently a residue of an amino acid or an amino acid analog; t is 0-50; z is 1-50; L is a linker moiety; TBT is a cellular receptor-binding moiety; each R^c is independently −L^a−R’; each of a and b is independently 1-200; each L^a is independently a covalent bond, or an optionally substituted bivalent group selected from a C₁-C₂₀ aliphatic group or a C₁-C₂₀ heteroaliphatic group having 1-5 heteroatoms, wherein one or more methylene units of the group are optionally and independently replaced with −C(R’)₂−, −Cy−, −O−, −S−, −S−S−, −N(R’)−, −C(O)−, −C(S)−, −C(NR’)−, −C(O)N(R’)−, −N(R’)C(O)N(R’)−, −N(R’)C(O)O−, −S(O)−, −S(O)₂−, −S(O)₂N(R’)−, −C(O)S−, or −C(O)O−; each −Cy− is independently an optionally substituted bivalent monocyclic, bicyclic, or polycyclic group wherein each monocyclic ring is independently selected from a C_3-20 cycloaliphatic ring, a C_6-20 aryl ring, a 5-20-membered heteroaryl ring having 1-10 heteroatoms independently selected from

23 30124-WO-PCT oxygen, nitrogen, sulfur, phosphorus, and silicon, and a 3-20-membered heterocyclyl ring having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus, and silicon; each R’ is independently −R, −C(O)R, −CO2R, or −SO2R; each R is independently −H, or an optionally substituted group selected from C_1-30 aliphatic, C_1-30 heteroaliphatic having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon, C_6-30 aryl, C_6-30 arylaliphatic, C_6-30 arylheteroaliphatic having 1-10 heteroatoms selected from oxygen, nitrogen, sulfur, phosphorus and silicon, 5-30-membered heteroaryl having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon, and 3-30-membered heterocyclyl having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon, or two R groups are optionally and independently taken together to form a covalent bond, or: two or more R groups on the same atom are optionally and independently taken with the atom to form an optionally substituted, 3-30-membered, monocyclic, bicyclic, or polycyclic ring having, in addition to the atom, 0-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon; or two or more R groups on two or more atoms are optionally and independently taken with their intervening atoms to form an optionally substituted, 3-30-membered, monocyclic, bicyclic, or polycyclic ring having, in addition to the intervening atoms, 0-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon. [0072] In some embodiments, a is 1. In some embodiments, b is 3. In some embodiments, a is 1 and b is 3. [0073] In some embodiments, the agent (TRAP) has the structure of formula AGN101: , or a wherein: each of a, b and c is independently 1-200; each AT is independently an anti-PLA2R antibody-binding moiety; L is a linker moiety; and each TBT is independently a cellular receptor-binding moiety, wherein the anti-PLA2R antibody-binding moiety is an anti-PLA2R antibody or an antigen- binding fragment thereof.

24 30124-WO-PCT [0074] In some embodiments, the agent (TRAP) has the structure of formula AGN102: , wherein: each of a and b is independently 1-200; each AT is independently an anti-PLA2R antibody-binding moiety; L is a linker moiety; and each TBT is independently a cellular receptor-binding moiety, wherein the anti-PLA2R antibody-binding moiety is an anti-PLA2R antibody or an antigen- binding fragment thereof. [0075] In some embodiments, an agent (TRAP) comprises one and no more than one anti-PLA2R antibody-binding moiety. In some embodiments, one or no more than one anti-PLA2R antibody-binding moiety is bound to a linker moiety. In some embodiments, a is 1. In some embodiments, an agent comprises two or more anti-PLA2R antibody moieties. In some embodiments, two or more anti-PLA2R antibody moieties are bound to a single linker moiety. In some embodiments, a is 2 or more. In some embodiments, one and no more than one cellular receptor-binding moiety is bonded to a linker moiety. In some embodiments, b is 1. In some embodiments, two or more cellular receptor-binding moiety is bonded to a single linker moiety. In some embodiments, b is 2 or more. In some embodiments, an agent comprises one and no more than one cellular receptor-binding moiety. In some embodiments, c is 1. In some embodiments, b is 1 and c is 1. In some embodiments, a is 1, b is 1 and c is 1. In some embodiments, an agent comprises two or more target-binding moieties. In some embodiments, b is 2 or more and c is 1. In some embodiments, b is 2 or more and c is 2 or more. In some embodiments, b is 1 and c is 2 or more. [0076] In some embodiments, c is 1-20, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. In some embodiments, c is selected from the Markush group of size ranges, where c is 1-15, c is 1-10, c is 1-9, c is 1-8, c is 1-7, c is 1-6, c is 1-5, c is 1-4, c is 1-3, and c is 1-2. In some embodiments, c is a size selected from the Markush group of sizes consisting of 1, 2, 3, 4, 5, 6, 7, 8, and 9. [0077] In some embodiments, each cellular receptor-binding moiety in an agent is the same. In some embodiments, each linker moiety connecting a cellular receptor-binding moiety to an antibody moiety is the same. In some embodiments, the TBT in agents is the same. In some embodiments, −L−(TBT)_b is the same.

25 30124-WO-PCT [0078] In some embodiments, b is 1. In some embodiments, c is 1. In some embodiments, c is two or more. In some embodiments, c is 2. Persons having ordinary skill in the biomedical art know that several technologies can conjugate antibody moieties with target-binding moieties, e.g., certain technologies used for preparing antibody-drug conjugates under this specification. In some embodiments, target-binding moieties are connected to antibody moieties through certain types of groups or amino acid residues. In some embodiments, target-binding moieties are connected to lysine residues optionally through linker moieties. In some embodiments, target-binding moieties are connected to cysteine residues optionally through linker moieties. In some embodiments, target-binding moieties are connected to unnatural amino acid residues optionally through linker moieties. In some embodiments, the invention provides technologies for selectively linking target-binding moieties to certain amino acid residues optionally through linker moieties. In some embodiments, provided technologies selectively connect target-binding moieties to certain types of amino acid residues, e.g., lysine residues, optionally through linker moieties. In some embodiments, provided technologies selectively connect target-binding moieties to sites of antibody moieties optionally through linker moieties. In some embodiments, provided technologies selectively connect target-binding moieties to certain types of amino acid residues at sites optionally through linker moieties. In some embodiments, target-binding moieties are connected to K246 and K248 of an IgG1 heavy chain and amino acid residues corresponding thereto optionally through linker moieties. In some embodiments, target-binding moieties are connected to K251 and K253 of an IgG2 heavy chain and amino acid residues corresponding thereto optionally through linker moieties. In some embodiments, target-binding moieties are connected to K239 and K241 of an anti-PLA2R antibody heavy chain and amino acid residues corresponding thereto optionally through linker moieties. In some embodiments, a cellular receptor- binding moiety is connected to a particular amino acid residue or site optionally through a linker. In some embodiments, each cellular receptor-binding moiety is independently connected to a particular amino acid residue or site optionally through a linker. As known by persons having ordinary skill in the biomedical art, an antibody agent may comprise more than one sites, e.g., one on each of the more than one chain, e.g., one or each heavy chain. In some embodiments, an antibody moiety comprises two heavy chains and one or both amino acid residues or amino acid residues corresponding thereto are each independently connected to a cellular receptor-binding moiety optionally through a linker. In some embodiments, one and no more than one is connected. In some embodiments, c is 1. In some embodiments, both are connected. In some embodiments, c is 2. In some embodiments, both target- binding moieties or both linker moieties (if any) are the same.

26 30124-WO-PCT The anti-PLA2R antibody-binding moiety [0079] In some embodiments, the anti-PLA2R antibody-binding moiety comprises a moiety selected from the Markush group consisting of one or more amino acid residues, a peptide moiety, a cyclic peptide moiety, a peptide comprising one or more natural amino acid residues, and a peptide comprising one or more unnatural natural amino acid residues. [0080] The anti-PLA2R antibody-binding moiety may be or may comprise: or a [0081] In some embodiments, the anti-PLA2R antibody-binding moiety comprises a moiety selected from the Markush group consisting of one or more amino acid residues, a peptide moiety, a cyclic peptide moiety, a peptide comprising one or more natural amino acid residues, and a peptide comprising one or more unnatural natural amino acid residues. [0082] In some embodiments, ABT101 is a universal antibody-binding moiety. In some embodiments, ABT101 is a universal antibody-binding moiety which can bind to anti-PLA2R antibody having different Fab regions. In some embodiments, ABT101 is a universal antibody-binding moiety that binds to a Fc region, e.g., the Fc region that binds to an Fc receptor. [0083] In some embodiments, the anti-PLA2R antibody-binding moiety comprises a universal antibody-binding moiety which recruit antibodies of diverse specificities, and no more than 1%, 2%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 99% percent of recruited antibodies are toward the same antigen, protein, lipid, carbohydrate, etc. An advantage of the invention is that provided technologies comprising universal antibody-binding moieties can use diverse pools of antibodies such as those present in serum. In some embodiments, universal antibody-binding moieties of this specification, e.g., those in ARMs, are contacted with a plurality of antibodies, wherein no more than 1%, 2%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 99% percent of the plurality of antibodies are toward the same antigen, protein, lipid, carbohydrate, etc. [0084] In some embodiments, the antibody-binding moiety is a universal antibody-binding moiety. In some embodiments, an antibody-binding moiety, e.g., a protein-binding moiety, e.g., an antibody-

27 30124-WO-PCT binding moiety, e.g., a universal antibody-binding moiety, comprises a peptide unit that can be connected to a linker moiety through the C-terminus of the peptide unit. In some embodiments, the antibody-binding moiety is connected to a linker moiety through the N-terminus of the peptide unit. In some embodiments, the antibody-binding moiety is connected to a linker through a side chain group of the peptide unit. In some embodiments, an antibody-binding moiety, e.g., a universal antibody-binding moiety comprises a peptide unit and is connected to an antibody-binding moiety optionally through a linker moiety through the C-terminus of the peptide unit. In some embodiments, the antibody-binding moiety, e.g., a protein-binding moiety, e.g., an antibody-binding moiety, e.g., a universal antibody- binding moiety, comprises a peptide unit connected optionally through a linker moiety through the N- terminus of the peptide unit. In some embodiments, an antibody-binding moiety, e.g., a protein-binding moiety, e.g., an antibody-binding moiety, e.g., a universal antibody-binding moiety, comprises a peptide unit connected optionally through a linker moiety through a side chain of the peptide unit. [0085] In some embodiments, the antibody-binding moiety comprises a universal antibody-binding moiety which can bind to anti-PLA2R antibody antibodies having different Fab regions. In some embodiments, the universal antibody-binding moiety binds to a Fc region, e.g., the Fc region that binds to an Fc receptor. [0086] Several antibody-binding moieties, including universal antibody-binding moieties, can be used under the teachings of this specification. Some antibody-binding moieties and technologies for identifying or assessing antibody-binding moieties are described in WO 2019/023501 and WO 2019/136442, each of which is incorporated in this specification in its entirety by reference. Persons having ordinary skill in the biomedical art know that additional technologies in the biomedical art may be suitable for identifying or assessing antibody-binding moieties under this specification. In some embodiments, an antibody-binding moiety comprises one or more amino acid residues, each independently natural or unnatural.

28 30124-WO-PCT [0087] In some embodiments, an anti-PLA2R antibody-binding moiety, e.g. a protein-binding moiety, e.g., an antibody-binding moiety, e.g., a universal antibody-binding moiety, has the structure of or a salt form thereof, wherein: each of R⁷ is independently hydrogen or an optionally substituted group selected from C_1-6 aliphatic, a 3-8-membered saturated or partially unsaturated monocyclic carbocyclic ring, phenyl, an 8- 10-membered bicyclic aromatic carbocyclic ring, a 4-8-membered saturated or partially unsaturated monocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur, a 5-6-membered monocyclic heteroaromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an 8-10-membered bicyclic heteroaromatic ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; or: an R⁷ group and the R^7’ group attached to the same carbon atom are optionally taken with their intervening carbon atom to form a 3-8-membered optionally substituted saturated or partially unsaturated spirocyclic carbocyclic ring or a 3-8-membered optionally substituted saturated or partially unsaturated spirocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur; each of R^7’ is independently hydrogen or optionally substituted C_1-3 aliphatic; each of R⁸ is independently hydrogen, or optionally substituted C1-4 aliphatic, or: an R⁸ group and its adjacent R⁷ group are optionally taken with their intervening atoms to form a 4-8-membered optionally substituted saturated or partially unsaturated monocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur; and R⁹ is hydrogen, optionally substituted C_1-3 aliphatic, or –C(O)−. [0088] In some embodiments, an anti-PLA2R antibody-binding moiety, e.g., a universal antibody- binding moiety is or comprises a peptide moiety, e.g., a moiety having the structure of R^c−(Xaa)z− or a salt form thereof, wherein each of R^c, z and Xaa is independently as described in this specification. One or more Xaa may be independently an unnatural amino acid residue. Side chains of two or more amino acid residues may be linked to form bridges. Side chains of two cysteine residues may form a disulfide bridge comprising −S−S−, which, as in many proteins, can be formed by two −SH groups.

29 30124-WO-PCT [0089] In some embodiments, an anti-PLA2R antibody-binding moiety, e.g. a protein-binding moiety, e.g., an antibody-binding moiety, e.g., a universal antibody-binding moiety, is or comprises a cyclic peptide moiety, e.g., a moiety having the structure of or a salt form thereof, wherein: each Xaa is independently a residue of an amino acid or an amino acid analog; t is 0-50; z is 1-50; each R^c is independently −L^a−R’; each L^a is independently a covalent bond, or an optionally substituted bivalent group selected from C₁-C₂₀ aliphatic or C₁-C₂₀ heteroaliphatic having 1-5 heteroatoms, wherein one or more methylene units of the group are optionally and independently replaced with −C(R’)₂−, −Cy−, −O−, −S−, −S−S−, −N(R’)−, −C(O)−, −C(S)−, −C(NR’)−, −C(O)N(R’)−, −N(R’)C(O)N(R’)−, −N(R’)C(O)O−, −S(O)−, −S(O)₂−, −S(O)₂N(R’)−, −C(O)S−, or −C(O)O−; each −Cy− is independently an optionally substituted bivalent monocyclic, bicyclic, or polycyclic group wherein each monocyclic ring is independently selected from a C_3-20 cycloaliphatic ring, a C_6-20 aryl ring, a 5-20-membered heteroaryl ring having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus, and silicon, and a 3-20-membered heterocyclyl ring having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus, and silicon; each R’ is independently −R, −C(O)R, −CO₂R, or −SO₂R; each R is independently −H, or an optionally substituted group selected from C_1-30 aliphatic, C_1-30 heteroaliphatic having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon, C_6-30 aryl, C_6-30 arylaliphatic, C_6-30 arylheteroaliphatic having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon, 5-30-membered heteroaryl having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon, and 3-30-membered heterocyclyl having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon, or two R groups are optionally and independently taken together to form a covalent bond, or: two or more R groups on the same atom are optionally and independently taken with the atom to form an optionally substituted, 3-30-membered, monocyclic, bicyclic, or polycyclic ring having, in addition to the atom, 0-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon; or

30 30124-WO-PCT two or more R groups on two or more atoms are optionally and independently taken with their intervening atoms to form an optionally substituted, 3-30-membered, monocyclic, bicyclic, or polycyclic ring having, in addition to the intervening atoms, 0-10 heteroatoms. [0090] In some embodiments, the heteroatom is independently selected from oxygen, nitrogen, sulfur, phosphorus, and silicon. [0091] Several antibody-binding moieties, including universal antibody-binding moieties, can be used under the teachings of this specification. Certain antibody-binding moieties and technologies for identifying or assessing antibody-binding moieties are described in WO2019/023501 and WO2019/136442, each of which is incorporated in this specification in its entirety by reference. Persons having ordinary skill in the biomedical art know that additional technologies in the biomedical art may be suitable for identifying or assessing antibody-binding moieties under this specification. In some embodiments, an antibody-binding moiety comprises one or more amino acid residues, each independently natural or unnatural. [0092] In some embodiments, an anti-PLA2R antibody-binding moiety, e.g., a protein-binding moiety, e.g., an antibody-binding moiety, e.g., a universal antibody-binding moiety, has the structure of or a salt form thereof, wherein: e^{ach of R1} _{, R} ³ _{and R} ⁵ _{is independently hydrogen or an optionally substituted group selected} from C_1-6 aliphatic, a 3-8-membered saturated or partially unsaturated monocyclic carbocyclic ring, phenyl, an 8-10-membered bicyclic aromatic carbocyclic ring, a 4-8-membered saturated or partially unsaturated monocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur, a 5-6-membered monocyclic heteroaromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an 8-10-membered bicyclic heteroaromatic ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; or: R¹ and R^1’ are optionally taken with their intervening carbon atom to form a 3-8-membered optionally substituted saturated or partially unsaturated spirocyclic carbocyclic ring or a 3-8-membered saturated or partially unsaturated spirocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur; R³ and R^3’ are optionally taken with their intervening carbon atom to form a 3-8-membered optionally substituted saturated or partially unsaturated spirocyclic carbocyclic ring or a 3-8-membered saturated or partially unsaturated spirocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur;

31 30124-WO-PCT an R⁵ group and the R^5’ group attached to the same carbon atom are optionally taken with their intervening carbon atom to form a 3-8-membered optionally substituted saturated or partially unsaturated spirocyclic carbocyclic ring or a 3-8-membered saturated or partially unsaturated spirocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur; or two R⁵ groups are optionally taken with their intervening atoms to form a C_1-10 optionally substituted bivalent straight or branched saturated or unsaturated hydrocarbon chain wherein 1-3 methylene units of the chain are independently and optionally replaced with –S–, –SS–, –N(R)–, –O–, – C(O)–, –OC(O)–, –C(O)O–, –C(O)N(R)–, –N(R)C(O)–, –S(O)–, –S(O)₂–, or –Cy¹–, wherein each –Cy¹– is independently a 5-6-membered heteroarylenyl with 1-4 heteroatoms independently selected from nitrogen, oxygen or sulfur; each of R^1’, R^3’ and R^5’ is independently hydrogen or optionally substituted C_1-3 aliphatic; each of R², R⁴ and R⁶ is independently hydrogen, or optionally substituted C_1-4 aliphatic, or: R² and R¹ are optionally taken with their intervening atoms to form a 4-8-membered, optionally substituted saturated or partially unsaturated monocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur; R⁴ and R³ are optionally taken with their intervening atoms to form a 4-8-membered optionally substituted saturated or partially unsaturated monocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur; or an R⁶ group and its adjacent R⁵ group are optionally taken with their intervening atoms to form a 4-8-membered optionally substituted saturated or partially unsaturated monocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur; L¹ is a trivalent linker moiety; and each of m and n is independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. [0093] In some embodiments, L¹ is an optionally substituted trivalent group selected from C₁-C₂₀ aliphatic or C₁-C₂₀ heteroaliphatic having 1-5 heteroatoms, wherein one or more methylene units of the group are optionally and independently replaced with −C(R’)₂−, −Cy−, −O−, −S−, −S−S−, −N(R’)−, −C(O)−, −C(S)−, −C(NR’)−, −C(O)N(R’)−, −N(R’)C(O)N(R’)−, −N(R’)C(O)O−, −S(O)−, −S(O)₂−, −S(O)₂N(R’)−, −C(O)S−, or −C(O)O−. In some embodiments L¹ is –(CH₂CH₂O)_2-4– or –(CH₂CH₂O)₂–.

32 30124-WO-PCT [0094] In some embodiments, an anti-PLA2R antibody-binding moiety, e.g. a protein-binding moiety, e.g., an antibody-binding moiety, e.g., a universal antibody-binding moiety, has the structure of or a salt form thereof, wherein: each of R⁷ is independently hydrogen or an optionally substituted group selected from C_1-6 aliphatic, a 3-8-membered saturated or partially unsaturated monocyclic carbocyclic ring, phenyl, an 8- 10-membered bicyclic aromatic carbocyclic ring, a 4-8-membered saturated or partially unsaturated monocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur, a 5-6-membered monocyclic heteroaromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an 8-10-membered bicyclic heteroaromatic ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; or: an R⁷ group and the R^7’ group attached to the same carbon atom are optionally taken with their intervening carbon atom to form a 3-8-membered optionally substituted saturated or partially unsaturated spirocyclic carbocyclic ring or a 3-8-membered optionally substituted saturated or partially unsaturated spirocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur; each of R^7’ is independently hydrogen or optionally substituted C_1-3 aliphatic; each of R⁸ is independently hydrogen, or optionally substituted C1-4 aliphatic, or: an R⁸ group and its adjacent R⁷ group are optionally taken with their intervening atoms to form a 4-8-membered optionally substituted saturated or partially unsaturated monocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur; and R⁹ is hydrogen, optionally substituted C_1-3 aliphatic, or –C(O)−. [0095] In some embodiments, an anti-PLA2R antibody-binding moiety, e.g., a universal antibody- binding moiety is or comprises a peptide moiety, e.g., a moiety having the structure of R^c−(Xaa)z− or a salt form thereof, wherein each of R^c, z and Xaa is independently as described in this specification. One or more Xaa may be independently an unnatural amino acid residue. Side chains of two or more amino acid residues may be linked to form bridges. Side chains of two cysteine residues may form a disulfide bridge comprising −S−S− (which, as in many proteins, can be formed by two −SH groups). [0096] In some embodiments, an anti-PLA2R antibody-binding moiety, e.g. a protein-binding moiety, e.g., an antibody-binding moiety, e.g., a universal antibody-binding moiety, is or comprises a cyclic peptide moiety, e.g., a moiety having the structure of or a salt form thereof, wherein: each Xaa is independently a residue of an amino acid or an amino acid analog; t is 0-50;

33 30124-WO-PCT z is 1-50; each R^c is independently −L^a−R’; each L^a is independently a covalent bond, or an optionally substituted bivalent group selected from C₁-C₂₀ aliphatic or C₁-C₂₀ heteroaliphatic having 1-5 heteroatoms, wherein one or more methylene units of the group are optionally and independently replaced with −C(R’)₂−, −Cy−, −O−, −S−, −S−S−, −N(R’)−, −C(O)−, −C(S)−, −C(NR’)−, −C(O)N(R’)−, −N(R’)C(O)N(R’)−, −N(R’)C(O)O−, −S(O)−, −S(O)₂−, −S(O)₂N(R’)−, −C(O)S−, or −C(O)O−; each −Cy− is independently an optionally substituted bivalent monocyclic, bicyclic, or polycyclic group wherein each monocyclic ring is independently selected from a C_3-20 cycloaliphatic ring, a C_6-20 aryl ring, a 5-20-membered heteroaryl ring having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus, and silicon, and a 3-20-membered heterocyclyl ring having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus, and silicon; each R’ is independently −R, −C(O)R, −CO₂R, or −SO₂R; each R is independently −H, or an optionally substituted group selected from C_1-30 aliphatic, C_1-30 heteroaliphatic having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, and silicon, C_6-30 aryl, C_6-30 arylaliphatic, C_6-30 arylheteroaliphatic having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon, 5-30-membered heteroaryl having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon, and 3-30-membered heterocyclyl having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon, or two R groups are optionally and independently taken together to form a covalent bond, or: two or more R groups on the same atom are optionally and independently taken with the atom to form an optionally substituted, 3-30-membered, monocyclic, bicyclic, or polycyclic ring having, in addition to the atom, 0-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon; or two or more R groups on two or more atoms are optionally and independently taken with their intervening atoms to form an optionally substituted, 3-30-membered, monocyclic, bicyclic, or polycyclic ring having, in addition to the intervening atoms, 0-10 heteroatoms. [0097] In some embodiments, the heteroatom is independently selected from oxygen, nitrogen, sulfur, phosphorus, and silicon. ^{[0098] In some embodiments, an anti-PLA2R antibody-binding moiety is or comprises Rc} _{−(Xaa)z− or} a salt form thereof, wherein each variable is as described in this specification.

34 30124-WO-PCT [0099] In some embodiments, a protein-binding moiety is or comprises R^c−(Xaa)z− or a salt form thereof, wherein each variable is as described in this specification. In some embodiments, a protein- binding moiety is or comprises ABT101 or a salt form thereof, wherein each variable is as described in this specification. [00100] In some embodiments, an anti-PLA2R antibody-binding moiety, e.g., a universal antibody- binding moiety, is or comprises R^c−(Xaa)z− or a salt form thereof, wherein each variable is as described in this specification. In some embodiments, an anti-PLA2R antibody-binding moiety, e.g., a universal antibody-binding moiety, is or comprises ABT101 or a salt form thereof, wherein each variable is as described in this specification. In some embodiments, an anti-PLA2R antibody-binding moiety, e.g., a universal antibody-binding moiety is R^c−(Xaa)z− or ABT101 , or a salt form thereof, and is or comprises a peptide unit. [00101] In some embodiments, −(Xaa)z− is or comprises a peptide unit. [00102] In some embodiments, amino acid residues may form bridges, e.g., connections formed by side chains optionally through linker moieties, e.g., L); for example, as in many polypeptides, cysteine residues may form disulfide bridges. [00103] In some embodiments, a peptide unit is or comprises a cyclic peptide unit. In some embodiments, a cyclic peptide unit comprises amide group formed by an amino group of a side chain and the C-terminus (−COOH). Persons having ordinary skill in the biomedical art know that in several embodiments, when a peptide unit is connected to another moiety, an amino acid residue of a peptide unit may be connected through several positions, e.g., its backbone, its side chain, etc. In embodiments, an amino acid residue is changed for connection. [00104] In some embodiments, X⁵ is Xaa^A or Xaa^P. In some embodiments, X⁵ is Xaa^A. In some embodiments, X⁵ is Xaa^P. In some embodiments, X⁵ is an amino acid residue whose side chain comprises an optionally substituted saturated, partially saturated, or aromatic ring. In some embodiments, X⁵ is . In some embodiments, X⁶ is selected from the Markush group of and His. In some embodiments, X¹² is selected from the Markush group of amino acids consisting of Xaa^A, . In some embodiments, X⁹ is selected from the and Glu. In some

35 30124-WO-PCT embodiments, each of X⁷, X¹⁰, and X¹¹ is independently an amino acid residue with a hydrophobic side chain (hydrophobic amino acid residue, Xaa^H). In some embodiments, X⁷ is selected from the Markush group of amino acids consisting In some embodiments, X¹⁰ is selected from the Markush group of amino acids In some embodiments, X¹¹ is selected from the Markush group of amino acids including Xaa^H . In some embodiments, X⁸ is Gly. In some embodiments, X⁴ is Pro. In some ³ X is Lys. In some embodiments, the −COOH of X¹² forms an amide bond with the side chain amino group of Lys (X³), and the other amino group of the Lys (X³) is connected to a linker moiety and then an anti-PLA2R antibody- binding moiety. [00105] In some embodiments, −(Xaa)z− is or comprises −X³X⁴X⁵X⁶X⁷X⁸X⁹X¹⁰X¹¹X¹²−, wherein: each of X³, X⁴, X⁵, X⁶, X⁷, X⁸, X⁹, X¹⁰, X¹¹, and X¹² is independently an amino acid residue; at least two amino acid residues are connected through one or more linkages L^b; L^b is an optionally substituted bivalent group selected from C₁-C₂₀ aliphatic or C₁-C₂₀ heteroaliphatic having 1-5 heteroatoms, wherein one or more methylene units of the group are optionally and independently replaced with −C(R’)₂−, −Cy−, −O−, −S−, −S−S−, −N(R’)−, −C(O)−, −C(S)−, −C(NR’)−, −C(O)N(R’)−, −N(R’)C(O)N(R’)−, −N(R’)C(O)O−, −S(O)−, −S(O)₂−, −S(O)₂N(R’)−, −C(O)S−, or −C(O)O−, wherein L^b is bonded to a backbone atom of one amino acid residue and a backbone atom of another amino acid residue, and comprises no backbone atoms; X⁶ is Xaa^A or Xaa^P; X⁹ is Xaa^N; and X¹² is Xaa^A or Xaa^P. [00106] In some embodiments, each of X³, X⁴, X⁵, X⁶, X⁷, X⁸, X⁹, X¹⁰, X¹¹, and X¹² is independently an amino acid residue of an amino acid of formula LNK101. In some embodiments, two non-neighboring amino acid residues are connected by L^b. In some embodiments, X⁵ and X¹⁰ are connected by L^b. In some embodiments, there is one linkage L^b. In some embodiments, X⁶ is an amino acid selected from the Markush group of amino acids consisting of Xaa^A, Xaa^P, and His. In some embodiments, X⁹ is Asp or Glu.

36 30124-WO-PCT In some embodiments, X¹² is an amino acid selected from the Markush group of amino acids consisting . In some is Xaa^H or Ala. In embodiments, X⁷ is Xaa^H. In some embodiments, X⁷ . In some embodiments, X¹¹ is Xaa^H some embodiments, X⁸ is Gly. In some embodiments, X³ is Lys. In some embodiments, forms an amide bond with the side chain amino group of Lys (X³), and the other amino group of the Lys (X³) is connected to a linker moiety and then an anti-PLA2R antibody-binding moiety. In some . In some embodiments, L^b is . In some embodiments, L^b connects two alpha-carbon atoms of two amino both X^{5 10} and X are Cys, and the two −SH groups of their side chains form −S−S− (L^b is −CH₂−S−S−CH₂−). [00107] In some embodiments, −(Xaa)z− is or comprises −X²X³X⁴X⁵X⁶X⁷X⁸X⁹X¹⁰X¹¹X¹²−, wherein: each of X², X³, X⁴, X⁵, X⁶, X⁷, X⁸, X⁹, X¹⁰, X¹¹, and X¹² is independently an amino acid residue; at least two amino acid residues are connected through one or more linkages L^b; L^b is an optionally substituted bivalent group selected from C₁-C₂₀ aliphatic or C₁-C₂₀ heteroaliphatic having 1-5 heteroatoms, wherein one or more methylene units of the group are optionally and independently replaced with −C(R’)₂−, −Cy−, −O−, −S−, −S−S−, −N(R’)−, −C(O)−, −C(S)−, −C(NR’)−, −C(O)N(R’)−, −N(R’)C(O)N(R’)−, −N(R’)C(O)O−, −S(O)−, −S(O)₂−, −S(O)₂N(R’)−, −C(O)S−, or −C(O)O−, wherein L^b is bonded to a backbone atom of one amino acid residue and a backbone atom of another amino acid residue, and comprises no backbone atoms; X⁴ is Xaa^A; X⁵ is Xaa^A or Xaa^P; X⁸ is Xaa^N; and X¹¹ is Xaa^A.

37 30124-WO-PCT [00108] In some embodiments, each of X², X³, X⁴, X⁵, X⁶, X⁷, X⁸, X⁹, X¹⁰, X¹¹, and X¹² is independently an amino acid residue of an amino acid of formula LNK101. In some embodiments, two non-neighboring amino acid residues are connected by L^b. In some embodiments, there is one linkage L^b. In some embodiments, X² and X¹² are connected by L^b. In some embodiments, L^b is a linker selected from the Markush group of linkers consisting of −CH₂−S−S−CH₂−, −CH₂−CH₂−S−CH₂−, , , and −CH₂CH₂CO−N(R’)−CH₂CH₂−. In some are with atom that −N(R’)−CH₂CH₂− is bonded to form a ring, e.g., as in A-34. In some embodiments, a formed ring is 3-, 4-, 5-, 6-, 7- or 8-membered. In some embodiments, a formed ring is monocyclic. In some embodiments, a formed ring is saturated. In some embodiments, L^b is . In some embodiments, L^b connects two alpha-carbon atoms of two amino acid X⁴ is Xaa^A or Tyr. I ⁵ n some embodiments, X is an amino acid selected from the Markush group of amino acids consisting of Xaa^A, Xaa^P, and His. In some embodiments, X⁸ is Asp or Glu. X¹¹ is Tyr. In some embodiments, both X² and X¹² are Cys, and the two −SH groups of their side chains form −S−S− (L^b is −CH₂−S−S−CH₂−). In some embodiments, each of X³, X⁶, X⁹, and X¹⁰ is independently Xaa^H. In some embodiments, X³ is Xaa^H or Ala. In embodiments, X⁶ is Xaa^H or Leu. In some embodiments, X⁹ is an amino acid selected from the Markush group of amino acids consisting of Xaa^H, Leu, . In some embodiments, X¹⁰ is an amino acid selected from the Markush group of amino acids some embodiments, X⁷ is Gly. In some embodiments, p1 is 1. In some embodiments, p13 is 1. In some embodiments, p14, p15 and p16 are 0. In some embodiments, X¹³ is an amino acid residue comprising a polar uncharged side chain, e.g., at physiological pH, polar uncharged amino acid residue, Xaa^L). In some embodiments, X¹³ is Thr. In some embodiments, X¹³ is Val. In some embodiments, p13 is 0. In some embodiments, R^c is −NHCH₂CH(OH)CH₃. In some embodiments, R^c is (R)−NHCH₂CH(OH)CH₃. In some embodiments, R^c is (S)−NHCH₂CH(OH)CH₃. [00109] In some embodiments, −(Xaa)z− is or comprises −X²X³X⁴X⁵X⁶X⁷X⁸X⁹X¹⁰X¹¹X¹²−, wherein:

38 30124-WO-PCT each of X², X³, X⁴, X⁵, X⁶, X⁷, X⁸, X⁹, X¹⁰, X¹¹, and X¹² is independently an amino acid residue; at least two amino acid residues are connected through one or more linkages L^b; L^b is an optionally substituted bivalent group selected from C1-C20 aliphatic or C1-C20 heteroaliphatic having 1-5 heteroatoms, wherein one or more methylene units of the group are optionally and independently replaced with −C(R’)₂−, −Cy−, −O−, −S−, −S−S−, −N(R’)−, −C(O)−, −C(S)−, −C(NR’)−, −C(O)N(R’)−, −N(R’)C(O)N(R’)−, −N(R’)C(O)O−, −S(O)−, −S(O)₂−, −S(O)₂N(R’)−, −C(O)S−, or −C(O)O−, wherein L^b is bonded to a backbone atom of one amino acid residue and a backbone atom of another amino acid residue, and comprises no backbone atoms; X⁵ is Xaa^A or Xaa^P; X⁸ is Xaa^N; and X¹¹ is Xaa^A. [00110] Persons having ordinary skill in the biomedical art know that an amino acid residue may be replaced by another amino acid residue having similar properties, e.g., one Xaa^H, e.g., Val, Leu, etc. may be replaced with another Xaa^H, e.g., Leu, Ile, Ala, etc. , one Xaa^A may be replaced with another Xaa^A, one Xaa^P may be replaced with another Xaa^P, one Xaa^N may be replaced with another Xaa^N, one Xaa^L may be replaced with another Xaa^L, etc. [00111] In some embodiments, the anti-PLA2R antibody-binding moiety is or comprises optionally substituted moiety disclosed in TABLE 2 of the published patent application WO 2024/228935 (Biohaven Therapeutics Ltd.). [00112] In some embodiments, an antibody-binding moiety is an antibody-binding moiety described in this specification. In some embodiments, a protein-binding moiety is an antibody-binding moiety described in this specification. In some embodiments, −COOH or amino groups of amino acid residues, e.g., those at the C-terminus or N-terminus, is optionally capped. In some embodiments, a −COOH group, e.g., a C-terminus −COOH) is amidated, e.g., converted into −CON(R’)₂, e.g., −C(O)NHR, e.g., −C(O)NH₂, and in some embodiments, an amino group, e.g. −NH₂, e.g., a N-terminus −NH₂) is capped with R’− or R’C(O)−, e.g., in some embodiments, by conversion −NH₂ into −NHR’, e.g., −NHC(O)R, e.g., −NHC(O)CH₃). [00113] In some embodiments, an antibody-binding moiety is or comprises (X_1-3)-C-(X₂)-H-(Xaa1)-G- (Xaa2)-L-V-W-C-(X_1-3), wherein each of X and Xaa is independently an amino acid residue and optionally not a cysteine residue. In some embodiments, Xaa1 is R, L, L, D, E, a 2-amino suberic acid residue, or a diaminopropionic acid residue. In some embodiments, Xaa1 is an arginine residue or a leucine residue. In some embodiments, Xaa2 is L, D, E, N, or Q. In embodiments, Xaa2 is a glutamic acid residue or an

39 30124-WO-PCT aspartic acid residue. In some embodiments, Xaa2 is a lysine residue, a glutamine residue, or an aspartic acid residue. In some embodiments, this antibody-binding moieties are antibody-binding moieties. [00114] In some embodiments, an antibody-binding moiety is or comprises (X1-3)-C-(Xaa3)-(xaa4)-H- (Xaa1)-G-(Xaa2)-L-V-W-C-(Xaa5)-(Xaa6)-(Xaa7), wherein each of X and Xaa is independently an amino acid residue and optionally not a cysteine residue. In some embodiments, Xaa3 is an alanine residue or a lysine residue. In some embodiments, Xaa4 is a tryptophan residue or a tyrosine residue. In some embodiments, Xaa1 is an arginine residue, a leucine residue, a lysine residue, an aspartic acid residue, a glutamic acid residue, a 2-amino suberic acid residue, or a diaminopropionic acid residue. In some embodiments, Xaa2 is a lysine residue, a glutamine residue, a glutamic acid residue, an asparagine residue, or an aspartic acid residue. In some embodiments, Xaa5 is a threonine residue or a lysine residue. In some embodiments, Xaa6 is a tyrosine residue, a lysine residue, or absent. In some embodiments, Xaa7 is a histidine residue, a lysine residue, or absent. In some embodiments, this antibody-binding moieties are antibody-binding moieties. [00115] In some embodiments, an antibody-binding moiety is or comprises D-C-(Xaa3)-(Xaa4)-H- (Xaa1)-G-(Xaa2)-L-V-W-C-(Xaa5)-(Xaa6)-(Xaa7), wherein each of X and Xaa is independently an amino acid residue and optionally not a cysteine residue. In some embodiments, Xaa3 is an alanine residue or a lysine residue. In some embodiments, Xaa4 is a tryptophan residue or a tyrosine residue. In some embodiments, Xaa1 is an arginine residue, a leucine residue, a lysine residue, an aspartic acid residue, a glutamic acid residue, a 2-amino suberic acid residue, or a diaminopropionic acid residue. In some embodiments, Xaa2 is a lysine residue, a glutamine residue, a glutamic acid residue, an asparagine residue, or an aspartic acid residue. In some embodiments, Xaa5 is a threonine residue or a lysine residue. In some embodiments, Xaa6 is a tyrosine residue, a lysine residue, or absent. In some embodiments, Xaa7 is a histidine residue, a lysine residue, or absent. In some embodiments, this antibody-binding moieties are antibody-binding moieties. [00116] In some embodiments, an antibody-binding moiety is or comprises D-C-(Xaa3)-(Xaa4)-H- (Xaa1)-G-(Xaa2)-L-V-W-C-T, wherein each of X and Xaa is independently an amino acid residue and optionally not a cysteine residue. In some embodiments, Xaa3 is an alanine residue or a lysine residue. In some embodiments, Xaa4 is a tryptophan residue or a tyrosine residue. In some embodiments, Xaa1 is an arginine residue, a leucine residue, a lysine residue, an aspartic acid residue, a glutamic acid residue, a 2-amino suberic acid residue, or a diaminopropionic acid residue. In some embodiments, Xaa2 is a lysine residue, a glutamine residue, a glutamic acid residue, an asparagine residue, or an aspartic acid residue. In some embodiments, this antibody-binding moieties are antibody-binding moieties.

40 30124-WO-PCT [00117] In some embodiments, an antibody-binding moiety is or comprises R-G-N-C-(Xaa3)-(Xaa4)- H-(Xaa1)-G-(Xaa2)-L-V-W-C-(Xaa5)- (Xaa6)-(Xaa7), wherein each of X and Xaa is independently an amino acid residue and optionally not a cysteine residue. In some embodiments, Xaa3 is an alanine residue or a lysine residue. In some embodiments, Xaa4 is a tryptophan residue or a tyrosine residue. In some embodiments, Xaa1 is an arginine residue, a leucine residue, a lysine residue, an aspartic acid residue, a glutamic acid residue, a 2-amino suberic acid residue, or a diaminopropionic acid residue. In some embodiments, Xaa2 is a lysine residue, a glutamine residue, a glutamic acid residue, an asparagine residue, or an aspartic acid residue. In some embodiments, Xaa5 is a threonine residue or a lysine residue. In some embodiments, Xaa6 is a tyrosine residue, a lysine residue, or absent. In some embodiments, Xaa7 is a histidine residue, a lysine residue, or absent. In some embodiments, this antibody-binding moieties are antibody-binding moieties. [00118] In some embodiments, antibody-binding moieties, e.g., several antibody-binding moieties described above, are protein-binding moieties. In some embodiments, antibody-binding moieties are antibody-binding moieties. In some embodiments, LG is or comprises this antibody-binding moiety. In some embodiments, LG is or comprises a protein-binding moiety. In some embodiments, LG is or comprises an antibody-binding moiety. [00119] In some embodiments, antibody-binding moieties, e.g., antibody-binding moieties, and useful technologies for developing or assessing such moieties are described in, e.g., Alves, Langmuir, 28, 9640−9648 (2012), Choe et al., Materials, 9, 994 (2016), Gupta et al., Nature Biomedical Engineering, 3, 917–929 (2019), Muguruma et al., ACS Omega, 4, 14390−14397 (2019), Yamada et al., Angew Chem. Int., Ed Engl.; 58(17), 5592-5597 (April 16, 2019), Kruljec et al., Bioconjugate Chem., 28(8): 2009-2030 (2017), e.g., Fabsorbent, triazines, etc.; Kruljec et al., Bioconjugate Chem., 29(8), 2763-2775 (2018), WO2012017021A2, etc., the-binding moieties, e.g., antibody-binding moieties) of each of which is incorporated in this specification in its entirety by reference. [00120] In some embodiments, an antibody-binding moiety, e.g., a protein-binding moiety, e.g., an antibody-binding moiety), is an affinity substance described in AU 2018259856 or WO 2018199337, the affinity substance of each of which is incorporated in this specification by reference. [00121] In some embodiments, an antibody-binding moiety, e.g., an antibody-binding moiety, is or comprises an adapter protein agent, e.g., as described in Hui et al., Bioconjugate Chem., 26, 1456−1460 (2015). In some embodiments, when used under this specification, adapter proteins do not require reactive residues, e.g., BPA, to achieve one or more or all advantages.

41 30124-WO-PCT [00122] In some embodiments, antibody-binding moiety, e.g., an antibody-binding moiety is or comprises a triazine moiety, e.g., one described in US 2009/0286693. In some embodiments, an antibody-binding moiety, e.g., an antibody-binding moiety is of such a structure that its corresponding compound is a compound described in US 2009/0286693, the compounds of which are independently incorporated in this specification by reference. In some embodiments, an antibody-binding moiety, e.g., an antibody-binding moiety, is ABT. In some embodiments, ABT is of such a structure that H−ABT is a compound described in US 2009/0286693, the compounds of which are independently incorporated in this specification by reference. In some embodiments, this compound can bind to an antibody. In some embodiments, this compound can bind to Fc region of an antibody. [00123] In some embodiments, an antibody-binding moiety, e.g., an antibody-binding moiety is or comprises a triazine moiety, e.g., one described in Teng et al., J. Mol. Recognit., 12, 67–75 (1999). In some embodiments, an antibody-binding moiety, e.g., an antibody-binding moiety is of such a structure that its corresponding compound is a compound described in Teng, the compounds of which are independently incorporated in this specification by reference. In some embodiments, an antibody- binding moiety, e.g., an antibody-binding moiety, ABT is of such a structure that H−ABT is a compound described in Teng, the compounds of which are independently incorporated in this specification by reference. In some embodiments, this compound can bind to an antibody. In some embodiments, this compound can bind to Fc region of an antibody. [00124] In some embodiments, an antibody-binding moiety, e.g., an antibody-binding moiety is a triazine moiety, e.g., one described in Uttamchandani, et al., J. Comb. Chem., 6(6), 862-8 (November- December 2004). In some embodiments, an antibody-binding moiety, e.g., an antibody-binding moiety is of such a structure that its corresponding compound is a compound described in Uttamchandani, the compounds of which are independently incorporated in this specification by reference. In some embodiments, an antibody-binding moiety, e.g., an antibody-binding moiety, ABT is of such a structure that H−ABT is a compound described in Uttamchandani, the compounds of which are independently incorporated in this specification by reference. In some embodiments, this compound can bind to an antibody. In some embodiments, this compound can bind to Fc region of an antibody. [00125] In some embodiments, an antibody-binding moiety binds to one or more-binding sites of a protein selected from the Markush group of proteins consisting of protein A, protein G, protein L, protein Z, protein LG, protein LA, and protein AG. In some embodiments, an antibody-binding moiety is described in Choe, Durgannavar, & Chung, Materials, 9(12) (2016).

42 30124-WO-PCT [00126] In some embodiments, an antibody-binding moiety, e.g., an antibody-binding moiety can bind to a nucleotide-binding site. In some embodiments, an antibody-binding moiety, e.g., an antibody- binding moiety is a small molecule moiety that can bind to a nucleotide-binding site. In some embodiments, a small molecule is tryptamine. In some embodiments, an antibody-binding moiety, e.g., an antibody-binding moiety, ABT is of such a structure that H−ABT is tryptamine. Certain useful technologies were described in Mustafaoglu et al., Analyst, 141(24), 6571–6582 (November 28, 2016). [00127] Many technologies are available for identifying, assessing, or characterizing antibody- binding moieties, including protein-binding moieties, e.g., antibody-binding moieties such as universal antibody-binding moieties), or their use in provided technologies, e.g., those described in Intl. Pat. Publ. WO 2019/023501, the technologies of which are incorporated in this specification by reference. In some embodiments, an antibody-binding moiety is a moiety, e.g., small molecule moiety, peptide moiety, nucleic acid moiety, etc., that can selectively bind to IgG, and when used in provided technologies can provide or stimulate ADCC or ADCP. In some embodiments, peptide display technologies, e.g., phase display, non-cellular display, etc., can identify antibody-binding moieties. In some embodiments, an antibody-binding moiety is a moiety, e.g., small molecule moiety, peptide moiety, nucleic acid moiety, etc., that can bind to IgG and optionally can compete with known antibody binders, e.g., protein A, protein G, protein L, etc. [00128] Persons having ordinary skill in the biomedical art know that antibodies of several properties and activities, e.g., antibodies recognizing different antigens, having optional changes, etc., may be targeted by antibody-binding moieties described in this specification. In some embodiments, such antibodies include antibodies administered to a subject, e.g., for therapeutic purposes. In some embodiments, antibody-binding moieties described in this specification may bind antibodies toward different antigens and are useful for conjugating moieties of interest with several antibodies. [00129] In some embodiments, an antibody-binding moiety, e.g., an antibody-binding moiety, is or comprises a meditope agent moiety. In some embodiments, a meditope agent is described in, e.g., US 2019/0111149. [00130] In some embodiments, an antibody-binding moiety, e.g., an antibody-binding moiety, can bind to human IgG. In some embodiments, an antibody-binding moiety, e.g., an antibody-binding moiety, can bind to an antibody selected from the Markush group of antibodies consisting of rabbit IgG, IgG1, IgG2, IgG3, and IgG4. In some embodiments, an antibody-binding moiety, e.g., an antibody-binding moiety, binds to IgG1, IgG2, and IgG4.

43 30124-WO-PCT [00131] In some embodiments is used in a reference technology as a non- antibody-binding moiety. In some mical group used in a reference technology as a non-antibody-binding moiety is selected from the Markush group of chemical groups consisting of CH₃−, CH₃C(O)−, CH₃C(O)NH−, CH₃C(O)NHCH₂−, CH₃CH₂−, CH₃CH₂NH−, and CH₃CH₂NHC(O)−. [00132] In some embodiments, antibody-binding moieties, e.g., antibody-binding moieties) bind to targets, e.g., antibody agents for antibody-binding moieties) with a K_D that is about 1 mM^-1 pM or less. In some embodiments, a K_D is about 1 mM, 0.5 mM, 0.2 mM, 0.1 mM, 0.05 mM, 0.02 mM, 0.01 mM, 0.005 mM, 0.002 mM, 0.001 mM, 500 nM, 200 nM, 100 nM, 50 nM, 20 nM, 10 nM, 5 nM, 2 nM, 1 nM, 0.5 nM, 0.2 nM, 0.1 nM, or less. In some embodiments, K_D is an affinity selected from the Markush group of affinities consisting of about 1 mM or less, about 0.5 mM or less, about 0.1 mM or less, about 0.05 mM or less, about 0.01 mM or less, about 0.005 mM or less, about 0.001 mM or less, about 500 nM or less, about 200 nM or less, about 100 nM or less, about 50 nM or less, about 20 nM or less, about 10 nM or less, about 5 nM or less, about 2 nM or less, and about 1 nM or less. In some embodiments, antibody- binding moieties bind to IgG antibody agents with K_D described in this specification. [00133] Persons having ordinary skill in the biomedical art know that antibodies of several properties and activities, e.g., antibodies recognizing different antigens, having optional changes, etc., may be recruited by antibody-binding moieties described in this specification. In some embodiments, such antibodies include antibodies administered to a subject, e.g., for therapeutic purposes. In some embodiments, antibodies recruited by antibody-binding moieties comprise antibodies toward different antigens. In some embodiments, antibodies recruited by antibody-binding moieties comprise antibodies whose antigens are not present on the surface or cell membrane of target cells. In some embodiments, antibodies recruited by antibody-binding moieties comprise antibodies not targeting antigens present on surface or cell membrane of targets. In some embodiments, antigens on surface of target cells may interfere with the structure, conformation, or one or more properties or activities of recruited antibodies which bind such antigens. In some embodiments, recruited antibodies are those in IVIG. In some embodiments, IVIG may be administered before, concurrently with or subsequently to an agent or composition. Antibodies of several types of immunoglobulin structures may be recruited. In some embodiments, one or more subclasses of IgG are recruited. In some embodiments, recruited antibodies are selected from the Markush group of antibody classes consisting of IgG1, IgG2, IgG3, and IgG4. In

44 30124-WO-PCT some embodiments, recruited antibodies are or comprise IgG1 and IgG2. In some embodiments, recruited antibodies are or comprise IgG1, IgG2 and IgG4. In some embodiments, recruited antibodies are or comprise IgG1, IgG2, IgG3 and IgG4. Recruited antibodies may interact several types of receptors, e.g., those expressed by several types of immune cells. In some embodiments, recruited antibodies can effectively interact several types of Fc receptors and provide desired immune activities. In some embodiments, recruited antibodies can recruit immune cells. In some embodiments, recruited antibodies can effectively interact with hFcγRIIIA. In some embodiments, recruited antibodies can effectively interact with hFcγRIIIA on macrophages. In some embodiments, macrophages are recruited to provide ADCC or ADCP activities toward a virus, e.g., a SARS-CoV-2 virus, or cells infected thereby. In some embodiments, NK cells are recruited to provide immune activities. In some embodiments, recruited antibodies can effectively interact with hFcγRIIA. In some embodiments, recruited antibodies can effectively interact with hFcγRIIA on dendritic cells. In some embodiments, antibody moieties in agents of this specification comprise one or more properties, structures or activities of recruited antibodies described in this specification. [00134] The ricin domain of PLA2R (rather than the fibronectin type II domain or the C-type lectin domains) has the major epitope on a PLA2R molecule. Peptide screening by competitive ELISA determined two peptides (fragment 1 and fragment 2) of the ricin domain bind the majority of anti- PLA2R antibodies. [00135] These two fragments were combined into one anti-PLA2R ligand. This 31-mer peptide from the ricin domain inhibits the binding of 80-85% of human anti-PLA2R to PLA2R. Anti-PLA2R antibodies can be effectively targeted by a single peptide. Other fragments (fragment 3, fragment 4, fragment 5, fragment 6, fragment 7) were less effective. One fragment (fragment 8) was ineffective. Fragment 1. WQDKGIFVIQSESLKKC (SEQ ID NO 1)(major epitope). Fragment 2. WSVLTENCK (SEQ ID NO 2) (major epitope). Fragment 3. TREGREDDLLWCATTSR (SEQ ID NO 3). Fragment 4. YLNHIQHEIVEKDAWK (SEQ ID NO 4). Fragment 5. YYATHCEPGWNPYNR (SEQ ID NO 5). Fragment 6. KEEKTWHEARLRSC (SEQ ID NO 6). Fragment 7. AGHVLSOAESGCQEGWER (SEQ ID NO 7). Fragment 8. PRYSGGCVAMRGRHP (SEQ ID NO 8). Synthetic 31-mer. WQDKGIFVIQSESLKKCIQAGKSVLTLENCK (SEQ ID NO 9).

45 30124-WO-PCT [00136] Most anti-PLA2R antibodies and ~90% of patient anti-PLA2R antibodies bind to the N-C3 domain of the PLA2R. Immunoreactive tryptic fragments of PLA2R were identified by mass spectrometry. Peptide screening by competitive ELISA determined two peptides of the ricin domain of PLA2R bind to most anti-PLA2R antibodies. [00137] These two fragments were combined into one anti-PLA2R ligand (31-mer). See SEQ ID NO: 9. The synthetic 31-mer binds anti-PLA2R antibodies strongly, K_D = 500 pM. TABLE 6 Biochemical selectivity. Binding Affinity (nM) # Anti-PLA2R ABT301 0.3 AGN302 10±3 AGN304 3±0.3 AGN303 7±1 AGN306 23±1 AGN307 7 Linker moiety [00138] In some embodiments, an amino acid has the structure of formula LNK101: NH(R^a1)−L^a1−C(R^a2)(R^a3)−L^a2−COOH, [LNK101] or a salt thereof, wherein: each of R^a1, R^a2, R^a3 is independently −L^a−R’; each of L^a1 and L^a2 is independently L^a; each L^a is independently a covalent bond, or an optionally substituted bivalent group selected from C₁-C₂₀ aliphatic or C₁-C₂₀ heteroaliphatic having 1-5 heteroatoms, wherein one or more methylene units of the group are optionally and independently replaced with −C(R’)₂−, −Cy−, −O−, −S−, −S−S−, −N(R’)−, −C(O)−, −C(S)−, −C(NR’)−, −C(O)N(R’)−, −N(R’)C(O)N(R’)−, −N(R’)C(O)O−, −S(O)−, −S(O)₂−, −S(O)₂N(R’)−, −C(O)S−, or −C(O)O−; each −Cy− is independently an optionally substituted bivalent monocyclic, bicyclic, or polycyclic group wherein each monocyclic ring is independently selected from a C_3-20 cycloaliphatic ring, a C_6-20 aryl ring, a 5-20-membered heteroaryl ring having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus, and silicon, and a 3-20-membered heterocyclyl ring having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus, and silicon; each R’ is independently −R, −C(O)R, −CO2R, or −SO2R;

46 30124-WO-PCT each R is independently −H, or an optionally substituted group selected from C_1-30 aliphatic, C_1-30 heteroaliphatic having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon, C6-30 aryl, C6-30 arylaliphatic, C6-30 arylheteroaliphatic having 1-10 heteroatoms selected from oxygen, nitrogen, sulfur, phosphorus and silicon, 5-30-membered heteroaryl having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon, and 3-30-membered heterocyclyl having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon, or two R groups are optionally and independently taken together to form a covalent bond, or: two or more R groups on the same atom are optionally and independently taken with the atom to form an optionally substituted, 3-30-membered, monocyclic, bicyclic, or polycyclic ring having, in addition to the atom, 0-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon; or two or more R groups on two or more atoms are optionally and independently taken with their intervening atoms to form an optionally substituted, 3-30-membered, monocyclic, bicyclic, or polycyclic ring having, in addition to the intervening atoms, 0-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus and silicon. [00139] In some embodiments, an amino acid residue has the structure of −N(R^a1)−L^a1−C(R^a2)(R^a3)−L^a2−COO− or a salt form thereof. [00140] In some embodiments, an amino acid analog is a compound in which the amino group or carboxylic acid group are independently replaced with an optionally substituted aliphatic or heteroaliphatic moiety. As persons having ordinary skill in the biomedical art know, many amino acid analogs, which mimics structures, properties or functions of amino acids, are described in the biomedical art and can be used under this specification, e.g., in several moieties. In some embodiments, one or more peptide groups are optionally and independently replaced with non-peptide groups. In some embodiments, an amino acid moiety in a polypeptide or peptide is replaced with an amino acid analog moiety. [00141] In some embodiments, the invention provides a derivative of an amino acid of formula LNK101 or a salt thereof. In some embodiments, a derivative is an ester. In some embodiments, the invention composes matter of formula NH(R^a1)−L^a1−C(R^a2)(R^a3)−L^a2−COOR^CT or salt thereof, wherein R^CT is R’ and each other variable is independently as described in this specification. In some embodiments, R^CT is R. In embodiments, R^CT is optionally substituted aliphatic. In some embodiments, R^CT is t-butyl.

47 30124-WO-PCT [00142] In some embodiments, L^a1 is a covalent bond. In some embodiments, a composition of matter of formula LNK101 is of the structure NH(R^a1)−C(R^a2)(R^a3)−L^a2−COOH. In some embodiments, L^a2 is −CH2SCH2−. [00143] In some embodiments, L^a2 is a covalent bond. In some embodiments, a composition of matter of formula LNK101 is of the structure NH(R^a1)−L^a1−C(R^a2)(R^a3)−COOH. In some embodiments, an amino acid residue has the structure of −N(R^a1)−L^a1−C(R^a2)(R^a3)−CO−. In some embodiments, L^a1 is −CH₂CH₂S−. In some embodiments, L^a1 is −CH₂CH₂S−, wherein the CH₂ is bonded to NH(R^a1). [00144] In some embodiments, L^a1 is a covalent bond and L^a2 is a covalent bond. In some embodiments, a composition of matter of formula LNK101 is of the structure NH(R^a1)−C(R^a2)(R^a3)−COOH. In some embodiments, a composition of matter of formula LNK101 is of the structure NH(R^a1)−CH(R^a2)−COOH. In some embodiments, a composition of matter of formula LNK101 has a structure selected from the Markush group of peptides consisting of NH(R^a1)−CH(R^a3)−COOH, NH₂−CH(R^a2)−COOH, NH₂−CH(R^a3)−COOH, −N(R^a1)−C(R^a2)(R^a3)−CO−, −N(R^a1)−CH(R^a2)−CO−, −N(R^a1)−CH(R^a3)−CO−, −NH−CH(R^a2)−CO−, and −NH−CH(R^a3)−CO−. [00145] In some embodiments, L^a is a covalent bond. In some embodiments, L^a is optionally substituted C_1-6 bivalent aliphatic. In some embodiments, L^a is optionally substituted C_1-6 alkylene. In some embodiments, L^a is −CH2−. In some embodiments, L^a is −CH2CH2−. In some embodiments, L^a is −CH₂CH₂CH₂−. [00146] In some embodiments, L^a is bivalent optionally substituted C_1-20 aliphatic, wherein one or more methylene units are independently replaced with −C(O)−, −N(R’)−, −Cy−, or −O−. In some embodiments, L^a is bivalent optionally substituted C_1-20 aliphatic, wherein one or more methylene units are independently replaced with −C(O)N(R’)−, −Cy−, and −O−. In some embodiments, L^a is bivalent optionally substituted C_1-20 aliphatic, wherein two or more methylene units are independently replaced with −C(O)N(R’)−, and −Cy− in addition to other optional replacements. In some embodiments, −Cy− is optionally substituted. In some embodiments, −Cy− is optionally substituted with an electron- withdrawing group as described in this specification. In some embodiments, −Cy− is substituted with one or more −F. In embodiments, −Cy− is optionally substituted 1,3-phenylene. In some embodiments, −Cy− is optionally substituted 1,4-phenylene. In some embodiments, L^a is or comprises a chemical group selected from the Markush group ,

48 30124-WO-PCT , s specification. In some embodiments, R^a1 is R, wherein R methyl. In some embodiments, R^a2 is R, wherein R is as described in this specification. In some embodiments, R^a3 is R, wherein R is as described in this specification. In some embodiments, each of R^a1, R^a2, and R^a3 is independently R, wherein R is as described in this specification. [00148] In some embodiments, R^a1 is hydrogen. In some embodiments, R^a1 is a protective group. In some embodiments, R^a1 is −Fmoc. In some embodiments, R^a1 is −Dde. [00149] In some embodiments, each of R^a1, R^a2 and R^a3 is independently −L^a−R’. [00150] In some embodiments, R^a2 is hydrogen. In some embodiments, R^a3 is hydrogen. In some embodiments, R^a1 is hydrogen, and at least one of R^a2 and R^a3 is hydrogen. In some embodiments, R^a1 is hydrogen, one of R^a2 and R^a3 is hydrogen, and the other is not hydrogen. In some embodiments, R^a2 is −L^a−R and R^a3 is −H. In embodiments, R^a3 is −L^a−R and R^a2 is −H. In embodiments, R^a2 is −CH₂−R and R^a3 is −H. In embodiments, R^a3 is −CH₂−R and R^a2 is −H. In embodiments, R^a2 is R and R^a3 is −H. In embodiments, R^a3 is R and R^a2 is −H. [00151] In some embodiments, R^a2 is −L^a−R, wherein R is as described in this specification. In some embodiments, R^a2 is −L^a−R, wherein R is an optionally substituted group selected from C_3-30 cycloaliphatic, C_5-30 aryl, 5-30-membered heteroaryl having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus, and silicon, and 3-30-membered heterocyclyl having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus, and silicon. In some

49 30124-WO-PCT embodiments, R^a2 is −L^a−R, wherein R is an optionally substituted group selected from C_6-30 aryl and 5- 30-membered heteroaryl having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus, and silicon. In some embodiments, R^a2 is a side chain of an amino acid. In some embodiments, R^a2 is a side chain of a standard amino acid. [00152] In some embodiments, R^a3 is −L^a−R, wherein R is as described in this specification. In some embodiments, R^a3 is −L^a−R, wherein R is an optionally substituted group selected from C_3-30 cycloaliphatic, C_5-30 aryl, 5-30-membered heteroaryl having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus, and silicon, and 3-30-membered heterocyclyl having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus, and silicon. In some embodiments, R^a3 is −L^a−R, wherein R is an optionally substituted group selected from C_6-30 aryl and 5- 30-membered heteroaryl having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus, and silicon. In some embodiments, R^a3 is a side chain of an amino acid. In some embodiments, R^a3 is a side chain of a standard amino acid. [00153] In some embodiments, one or R^a2 and R^a3 is −H. In embodiments, one or R^a2 and R^a3 is −L^a−R, wherein L^a is as described in this specification. In some embodiments, L^a is not a covalent bond. In some embodiments, one or more methylene units of L^a are independently and optionally replaced as described in this specification, e.g., with −C(O)−, −N(R’)−, −O−, −C(O)−N(R’)− or −Cy−, etc. In embodiments, L^a is or comprises −C(O)−, −N(R’)− and −Cy−. In some embodiments, L^a is or comprises −C(O)N(R’)− and −Cy−. In some embodiments, −Cy− is substituted and one or more substituents are independently an electron-withdrawing group. [00154] In some embodiments, an amino acid side chain is R^a2 or R^a3. In some embodiments, an amino acid side chain is or comprises −L^LG1−L^LG2−L^LG3−L^LG4−H. In embodiments, an amino acid side chain is or comprises −L^LG2−L^LG3−L^LG4−H. In embodiments, an amino acid side chain is or comprises −L^LG3−L^LG4−H. In embodiments, an amino acid side chain is or comprises −L^LG4−H. In embodiments, this side chain selected from the Markush group , .

50 30124-WO-PCT [00155] In some embodiments, R is an optionally a group selected from the Markush group consisting of substituted C_1-6 aliphatic, substituted C_1-6 alkyl, −CH₃, pentyl, and n-pentyl. [00156] In some embodiments, R is a cyclic group. In some embodiments, R is an optionally substituted C_3-30 cycloaliphatic group. In some embodiments, R is cyclopropyl. [00157] In some embodiments, R is an optionally substituted aromatic group, and an amino acid residue of an amino acid of formula LNK101 is a Xaa^A. In some embodiments, R^a2 or R^a3 is −CH₂−R, wherein R is an optionally substituted aryl or heteroaryl group. In some embodiments, R is an amino acid selected from the Markush group of amino acids consisting of optionally substituted phenyl, phenyl, 4-trifluoromethylphenyl, and 4-phenylphenyl. In some embodiments, R is optionally substituted 5-30- membered heteroaryl having 1-10 heteroatoms independently selected from oxygen, nitrogen, sulfur, phosphorus, and silicon. In some embodiments, R is optionally substituted 5-14-membered heteroaryl having 1-5 heteroatoms independently selected from oxygen, nitrogen, and sulfur. In some embodiments, R is . In some embodiments, R is optionally substituted pyridinyl. In some embodiments, R is In some embodiments, R is 2- pyridinyl. In some embodiments, R is 3- pyridinyl. In some embodiments, R is. [00158] In some embodiments, R’ is−COOH. In some embodiments, a compound of and an amino acid residue of an amino acid of formula LNK101 is a Xaa^N. [00159] In some embodiments, R’ is−NH₂. In some embodiments, a compound of an amino acid residue of an amino acid of formula LNK101 is a Xaa^P. [00160] In some embodiments, R^a2 or R^a3 is R, wherein R is C_1-20 aliphatic. In some embodiments, a compound of an amino acid residue of an amino acid of formula LNK101 is a Xaa^H. In some embodiments, R is −CH₃. In some embodiments, R is ethyl. In some embodiments, R is propyl. In some embodiments, R is n-propyl. In some embodiments, R is butyl. In some embodiments, R is n-butyl. In some embodiments, R is pentyl. In some embodiments, R is n-pentyl. In some embodiments, R is cyclopropyl. [00161] In some embodiments, two or more of R^a1, R^a2, and R^a3 are R and are taken together to form an optionally substituted ring as described in this specification. [00162] In some embodiments, R^a1 and one of R^a2 and R^a3 are R and are taken together to form an optionally substituted 3-6-membered ring having no additional ring heteroatom other than the nitrogen atom to which R^a1 is bonded to. In some embodiments, a formed ring is a 5-membered ring as in proline.

51 30124-WO-PCT [00163] In some embodiments, R^a2 and R^a3 are R and are taken together to form an optionally substituted 3-6-membered ring. In some embodiments, R^a2 and R^a3 are R and are taken together to form an optionally substituted 3-6-membered ring having one or more nitrogen ring atom. In some embodiments, R^a2 and R^a3 are R and are taken together to form an optionally substituted 3-6-membered ring having one and no more than one ring heteroatom which is a nitrogen atom. In some embodiments, a ring is a saturated ring. [00164] In some embodiments, an amino acid is an amino acid selected from the Markush group of amino acids consisting of a natural amino acid, an unnatural amino acid, an alpha-amino acid, and a beta-amino acid. In some embodiments, a composition of matter of formula LNK101 is a natural amino acid or unnatural amino acid. [00165] In some embodiments, an amino acid comprises a hydrophobic side chain. In some embodiments, an amino acid with a hydrophobic side chain is A, V, I, L, M, F, Y or W. In embodiments, an amino acid with a hydrophobic side chain is A, V, I, L, M, or F. In embodiments, an amino acid with a hydrophobic side chain is A, V, I, L, or M. In embodiments, an amino acid with a hydrophobic side chain is A, V, I, or L. In embodiments, a hydrophobic side chain is R wherein R is C_1-10 aliphatic. In some embodiments, R is C_1-10 alkyl. In some embodiments, R is methyl. In some embodiments, R is ethyl. In some embodiments, R is propyl. In some embodiments, R is butyl. In some embodiments, R is pentyl. In some embodiments, R is n-pentyl. In some embodiments, an amino acid with a hydrophobic side chain is NH₂CH(CH₂CH₂CH₂CH₂CH₃)COOH. In some embodiments, an amino acid with a hydrophobic side chain is (S)-NH₂CH(CH₂CH₂CH₂CH₂CH₃)COOH. In some embodiments, an amino acid with a hydrophobic side chain is (R)-NH₂CH(CH₂CH₂CH₂CH₂CH₃)COOH. In some embodiments, a hydrophobic side chain is −CH₂R wherein R is optionally substituted phenyl. In some embodiments, R is phenyl. In some embodiments, R is phenyl substituted with one or more hydrocarbon group. In some embodiments, R is 4-phenylphenyl. In some embodiments, an amino acid with a hydrophobic side chain is NH₂CH(CH₂−4- phenylphenyl)COOH. In some embodiments, an amino acid with a hydrophobic side chain is (S)- NH₂CH(CH₂−4-phenylphenyl)COOH. In some embodiments, an amino acid with a hydrophobic side chain is (R)-NH₂CH(CH₂−4-phenylphenyl)COOH. [00166] In some embodiments, an amino acid comprises a positively charged side chain, e.g., at physiological pH. In some embodiments, this amino acid comprises a basic nitrogen in its side chain. In some embodiments, this amino acid is Arg, His or Lys. In some embodiments, this amino acid is Arg. In some embodiments, this amino acid is His. In some embodiments, this amino acid is Lys.

52 30124-WO-PCT [00167] In some embodiments, an amino acid comprises a negatively charged side chain, e.g., at physiological pH. In some embodiments, this amino acid comprises a −COOH in its side chain. In some embodiments, this amino acid is Asp. In some embodiments, this amino acid is Glu. [00168] In some embodiments, an amino acid comprises a side chain comprising an aromatic group. In some embodiments, this amino acid is Phe, Tyr, Trp, or His. In some embodiments, this amino acid is Phe. In some embodiments, this amino acid is Tyr. In some embodiments, this amino acid is Trp. In some embodiments, this amino acid is His. In some embodiments, this amino acid is NH₂−CH(CH₂−4- phenylphenyl)−COOH. In some embodiments, this amino acid is (S)-NH₂−CH(CH₂−4- phenylphenyl)−COOH. In some embodiments, this amino acid is (R)-NH₂−CH(CH₂−4- phenylphenyl)−COOH. [00169] In some embodiments, an amino acid is an amino acid selected from the Markush group of a salt thereof. In some embodiments, a provided compound is

53 30124-WO-PCT . In some embodiments, the invention provides polypeptide agents id residues described in this specification. Amino acids [00170] In some embodiments, each residue is independently a residue of an amino acid or an amino acid analog, e.g., Xaa, wherein the amino acid or the amino acid analog has the structure of H−L^a1−L^a1−C(R^a2)(R^a3)−L^a2−L^a2−H or a salt thereof. In some embodiments, an amino acid has the structure of NH(R^a1)−L^a1−C(R^a2)(R^a3)−L^a2−COOH or a salt thereof. In some embodiments, an amino acid analog has the structure of H−L^a1−L^a1−C(R^a2)(R^a3)−L^a2−L^a2−H or a salt thereof. In some embodiments, in this amino acid analog, the first −L^a1− (bonded to –H in the formula) is not − N(R^a1)−, e.g., is optionally substituted bivalent C_1-6 aliphatic. In some embodiments, in H−L^a1−L^a1−, −L^a1−L^a1− bonds to the –H through an atom that is not nitrogen. In some embodiments, in −L^a2−L^a2−H, −L^a2−L^a2− is not bonded to the –H through – C(O)O−. [00171] In some embodiments, each Xaa independently has the structure of −L^a1−L^a1−C(R^a2)(R^a3)−L^a2−L^a2−. In some embodiments, each Xaa independently has the structure of – L^aX1−L^a1−C(R^a2)(R^a3)−L^a2−L^aX2−, wherein L^aX1 is optionally substituted −NH−, optionally substituted −CH₂−, − N(R^a1)−, or −S−, L^aX2 is optionally substituted −NH−, optionally substituted −CH₂−, − N(R^a1)−, or −S−, and each other variable is independently as described in this specification. In some embodiments, L^aX1 is optionally substituted −NH−, or − N(R^a1)−. In some embodiments, L^aX1 is optionally substituted −CH₂−, or −S−. In some embodiments, L^aX2 is optionally substituted −NH−, optionally substituted −CH₂−, − N(R^a1)−, or −S−. In some embodiments, optionally substituted −CH₂− is −C(O)−. In some embodiments, optionally substituted −CH₂− is not −C(O)−. In some embodiments, L^aX2 is −C(O)−. In some embodiments, each Xaa independently has the structure of −N(R^a1)−L^a1−C(R^a2)(R^a3)−L^a2−CO−. [00172] In some embodiments, two or more residues, e.g., two or more Xaa residues, are linked such that one or more cyclic structures are formed. Residues can be linked, optionally through a linker, e.g., L^T) at any suitable positions. A linkage between two residues can connect each residue independently at its N-terminus, C-terminus, a point on the backbone, or a point on a side chain, etc. In embodiments, two or more side chains of residues, e.g., in compounds of formula AGN105, e.g., R^a2 or R^a3 of one amino acid residue with R^a2 or R^a3 of another amino acid residue, are optionally take together

54 30124-WO-PCT to form a bridge, e.g., in some embodiments, two cysteine residues form a −S−S− bridge as typically observed in natural proteins. [00173] In some embodiments, an amino acid residue has the structure of −N(R^a1)−L^a1−C(R^a2)(R^a3)−L^a2−COO− or a salt form thereof. [00174] In some embodiments, an amino acid analog is a compound in which the amino group or carboxylic acid group are independently replaced with an optionally substituted aliphatic or heteroaliphatic moiety. As persons having ordinary skill in the biomedical art know, many amino acid analogs, which mimics structures, properties or functions of amino acids, are described in the biomedical art and can be used under this specification, e.g., in several moieties. In some embodiments, one or more peptide groups are optionally and independently replaced with non-peptide groups. In some embodiments, an amino acid moiety in a polypeptide or peptide is replaced with an amino acid analog moiety. [00175] In some embodiments, moieties are optionally connected to each other through linker moieties. In some embodiments, a reactive group, e.g., RG, is connected to a cellular receptor-binding moiety, e.g., TBT, through a linker, e.g., L^RM. In some embodiments, a moiety, e.g., LG, may also comprise one or more linkers, e.g., L^LG1, L^LG2, L^LG3, L^LG4, etc., to link several parts. In some embodiments, L^LG is a linker moiety described in this specification. In some embodiments, L^LG1 is a linker moiety described in this specification. In some embodiments, L^LG2 is a linker moiety described in this specification. In some embodiments, L^LG3 is a linker moiety described in this specification. In some embodiments, L^LG4 is a linker moiety described in this specification. In some embodiments, L^RM is a linker moiety described in this specification. In some embodiments, L^PM is L. In embodiments, L^PM is a linker moiety described in this specification. In some embodiments, L^PM is L. [00176] Linker moieties of several types or for several purposes, e.g., those used in antibody-drug conjugates, etc., may be used under this specification. [00177] Linker moieties can be bivalent or polyvalent depending on how they are used. In some embodiments, a linker moiety is bivalent. In some embodiments, a linker is polyvalent and connecting over two moieties. [00178] In some embodiments, L is bivalent. In some embodiments, L is a covalent bond. [00179] In some embodiments, a linker moiety, or L, is or comprises −(CH₂CH₂O)n−, wherein each −CH2− is independently and optionally substituted and n is 1-20. In some embodiments, a linker moiety,

55 30124-WO-PCT or L, is or comprises −(CH₂)n−O−(CH₂CH₂O)n−(CH₂)n−, wherein each n is independently 1-10, and each −CH₂− is independently and optionally substituted. [00180] In some embodiments, a linker moiety is trivalent or polyvalent. In some embodiments, a linker moiety is L, where L is trivalent or polyvalent. In some embodiments, L is trivalent. In some embodiments, L is −CH₂−N(−CH₂−)−C(O)−. [00181] In some embodiments, a linker moiety, e.g., L, comprises one or more amino acid residues or analogs thereof. [00182] In some embodiments, a linker moiety, e.g., L, L^RM, etc., is or comprises a reactive group as described in this specification. In some embodiments, an agent (a TRAP) comprises an antibody-binding moiety and a cellular receptor-binding moiety linked through a linker which is or comprises a reactive group. In some embodiments, a reactive group can react with a lysine residue of an antibody in an aqueous buffer. In some embodiments, a reactive group is or comprises −C(O)−O−. In some embodiments, a reactive group is or comprises −C(O)−O−, wherein −O− is bonded to an optionally substituted aryl group. In some embodiments, a reactive group is or comprises −C(O)−O−, wherein −O− is bonded to an aryl group substituted with one or more electron-withdrawing groups. In some embodiments, one or more or each electron-withdrawing group is independently selected from −NO₂ and −F. In embodiments, an aryl group has the structure , wherein R^s is halogen, −NO₂, - F, −L−R’, −C(O)−L−R’, −S(O)−L−R’, −S(O)₂−L−R’, or −P(O) embodiments, an aryl group has the , wherein each R^s is independently halogen, −NO₂, -F, −L−R’, −C(O)−L−R’, −S(O)−L−R’, −S(O)₂−L−R’, or −P(O)(−L−R’)₂. In some embodiments, an aryl embodiments, an aryl In some embodiments, C1 is bound to the −O− of −C(O)−O−. In some embodiments, a moiety is at the side of −C(O)− and an antibody- binding moiety is at the side of −O−. [00183] In some embodiments, a linker moiety, e.g., L, L^RM, etc., comprises a reactive group, wherein upon contact with an antibody, the reactive group reacts with a group of the antibody and conjugates a

56 30124-WO-PCT cellular receptor-binding moiety, or a moiety comprising −(Xaa)y−, to the antibody optionally through a linker. In some embodiments, a reactive group is or comprises , wherein the −C(O)− is connected to a cellular receptor-binding moiety, or a moiety comprising −(Xaa)y−, optionally through a linker. In some embodiments, a reactive group is or comprises , wherein the −C(O)− is connected to a cellular receptor-binding moiety, or a moiety comprising −(Xaa)y−, optionally through a linker and the other end of the reactive group is connected to an antibody-binding moiety. [00184] In some embodiments, a linker moiety, e.g., L, L^RM, etc., does not have a reactive group. In some embodiments, a linker moiety, e.g., L, L^RM, etc., does not have a reactive group that readily reacts with proteins under aqueous conditions with pH about 6-9, e.g., physiological conditions. In some embodiments, a linker moiety, e.g., L, L^RM, etc., does not have a reactive group that readily reacts with natural amino acid residues under aqueous conditions with pH about 6-9, e.g., physiological conditions. [00185] In some embodiments, a linker moiety, e.g., L, L^RM, etc., comprises no −S−, wherein none of the two atoms to which the −S− is bonded to is S. In embodiments, a linker moiety, e.g., L, L^RM, etc., comprises no −S−S−. In some embodiments, a linker moiety, e.g., L, L^RM, etc., comprises no −S− bonded to a beta carbon of a carbonyl group or a double or triple bond conjugated to a carbonyl group. In some embodiments, a linker moiety, e.g., L, L^RM, etc., In some embodiments, a linker moiety, e.g., L, L^RM, etc., comprises no −S−. [00186] In some embodiments, an agent (a TRAP) comprises no cleavable groups whose cleavage can release LG except one or more optionally in RG. In some embodiments, an agent comprises no −S−S−, acetal or imine groups except in RG or TBT. In some embodiments, an agent comprises no −S−S−, acetal or imine groups except that the agent may have −S−S− formed by two amino acid residues. In some embodiments, an agent comprises no −S−S−, acetal or imine groups except that the agent may have −S−S− formed by cysteine residues. In some embodiments, an agent comprises no −S−S−, acetal or imine groups. [00187] In some embodiments, L is a covalent bond. In some embodiments, L is a bivalent optionally substituted, linear or branched C_1-100 aliphatic group wherein one or more methylene units of the group

57 30124-WO-PCT are optionally and independently replaced. In some embodiments, L is a bivalent optionally substituted, linear or branched C_6-100 arylaliphatic group wherein one or more methylene units of the group are optionally and independently replaced. In some embodiments, L is a bivalent optionally substituted, linear or branched C_5-100 heteroarylaliphatic group having 1-20 heteroatoms wherein one or more methylene units of the group are optionally and independently replaced. In some embodiments, L is a bivalent optionally substituted, linear or branched C_1-100 heteroaliphatic group having 1-20 heteroatoms wherein one or more methylene units of the group are optionally and independently replaced. [00188] In some embodiments, a linker moiety, e.g., L) is or comprises one or more, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more) polyethylene glycol units. In some embodiments, a linker moiety is or comprises −(CH₂CH₂O)_n−, wherein n is as described in this specification. In some embodiments, one or more methylene units of L are independently replaced with −(CH₂CH₂O)_n−. [00189] In some embodiments, n is 1. In some embodiments, n is 2. In some embodiments, n is 3. In some embodiments, n is 4. In some embodiments, n is 5. In some embodiments, n is 6. In some embodiments, n is 7. In some embodiments, n is 8. In some embodiments, n is 9. In some embodiments, n is 10. In some embodiments, n is 11. In some embodiments, n is 12. In some embodiments, n is 13. In some embodiments, n is 14. In some embodiments, n is 15. In some embodiments, n is 16. In some embodiments, n is 17. In some embodiments, n is 18. In some embodiments, n is 19. In some embodiments, n is 20. [00190] In some embodiments, a linker moiety, e.g., L) is or comprises one or more, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more) amino acid residues. As used in this specification, “one or more” can be 1-100, 1-50, 1-40, 1-30, 1-20, 1-10, 1-5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 or more. In some embodiments, one or more methylene units of L are independently replaced with an amino acid residue. In some embodiments, one or more methylene units of L are independently replaced with an amino acid residue, wherein the amino acid residue is of an amino acid of formula LNK101 or a salt thereof. In some embodiments, one or more methylene units of L are independently replaced with an amino acid residue, wherein each amino acid residue independently has the structure of −N(R^a1)−L^a1−C(R^a2)(R^a3)−L^a2−CO− or a salt form thereof. [00191] In some embodiments, a linker moiety comprises one or more moieties, e.g., amino, carbonyl, etc., that can be used for connection with other moieties. In some embodiments, a linker moiety comprises one or more −NR’−, wherein R’ is as described in this specification. In some embodiments, −NR’− improves solubility. In some embodiments, −NR’− serves as connection points to

58 30124-WO-PCT another moiety. In some embodiments, R’ is −H. In embodiments, one or more methylene units of L are independently replaced with −NR’−, wherein R’ is as described in this specification. [00192] In some embodiments, a linker moiety, e.g., L, comprises a −C(O)− group, which can be used for connections with a moiety. In some embodiments, one or more methylene units of L are independently replaced with −C(O)−. [00193] In some embodiments, a linker moiety, e.g., L, comprises a −NR’− group, which can be used for connections with a moiety. In some embodiments, one or more methylene units of L are independently replaced with −N(R’)−. [00194] In some embodiments, a linker moiety, e.g., L, comprises a −C(O)NR’− group, which can be used for connections with a moiety. In some embodiments, one or more methylene units of L are independently replaced with −C(O)N(R’)−. [00195] In some embodiments, a linker moiety, e.g., L, comprises a −C(R’)₂− group. In some embodiments, one or more methylene units of L are independently replaced with −C(R’)₂−. In some embodiments, −C(R’)₂− is −CHR’−. In some embodiments, R’ is −(CH₂)₂C(O)NH(CH₂)₁₁COOH. In some embodiments, R’ is −(CH₂)₂COOH. In some embodiments, R’ is −COOH. [00196] In some embodiments, a linker moiety is or comprises one or more ring moieties, e.g., one or more methylene units of L are replaced with −Cy−. In some embodiments, a linker moiety, e.g., L, comprises an aryl ring. In some embodiments, a linker moiety, e.g., L, comprises an heteroaryl ring. In some embodiments, a linker moiety, e.g., L, comprises an aliphatic ring. In some embodiments, a linker moiety, e.g., L, comprises an heterocyclyl ring. In some embodiments, a linker moiety, e.g., L, comprises a polycyclic ring. In some embodiments, a ring in a linker moiety, e.g., L, is 3-20-membered. In some embodiments, a ring is 5-membered. In some embodiments, a ring is 6-membered. In some embodiments, a ring in a linker is product of a cycloaddition reaction, e.g., click chemistry, and variants thereof) used to link different moieties. [00197] In some embodiments, L is L¹. In some embodiments, L is L^b. [00198] In some embodiments, L^RM is a covalent bond. In some embodiments, L^RM is not a covalent bond. In some embodiments, L^RM is or comprises −(CH₂CH₂O)n−. In some embodiments, L^RM is or comprises −(CH₂)n−O−(CH₂CH₂O)n−(CH₂)n−, wherein each n is independently as described in this specification, and each −CH₂− is independently optionally substituted. In some embodiments, L^RM is −(CH₂)n−O−(CH₂CH₂O)n−(CH₂)n−, wherein each n is independently as described in this specification, and each −CH2− is independently optionally substituted. In some embodiments, L^RM is −(CH₂)₂−O−(CH₂CH₂O)n−(CH₂)₂−, wherein n is as described in this specification, and each −CH₂− is

59 30124-WO-PCT independently optionally substituted. In some embodiments, L^RM is −(CH₂)₂−O−(CH₂CH₂O)n−(CH₂)₂−, wherein n is as described in this specification. [00199] In some embodiments, L^PM is a covalent bond. In some embodiments, L^PM is not a covalent bond. In some embodiments, L^PM is or comprises −(CH₂CH₂O)n−. In some embodiments, L^PM is or comprises −(CH₂)n−O−(CH₂CH₂O)n−(CH₂)n−, wherein each n is independently as described in this specification, and each −CH₂− is independently optionally substituted. In some embodiments, L^PM is −(CH₂)n−O−(CH₂CH₂O)n−(CH₂)n−, wherein each n is independently as described in this specification, and each −CH₂− is independently optionally substituted. In some embodiments, L^PM is −(CH₂)₂−O−(CH₂CH₂O)n−(CH₂)₂−, wherein n is as described in this specification, and each −CH₂− is independently optionally substituted. In some embodiments, L^PM is −(CH₂)₂−O−(CH₂CH₂O)n−(CH₂)₂−, wherein n is as described in this specification. [00200] In some embodiments, L^PM, e.g., in a product of a first and a second agents) is or comprises a reaction product moiety formed a first reactive moiety and a second reactive moiety. Cellular receptor-binding moiety [00201] Several receptor-binding moieties, according to embodiments of present invention, are described in WO2019/199621A1 published October 17, 2019, WO2019/199634 published October 17, 2019, International Application No. PCT/US2020/055053 filed October 9, 2020, and International Application No. PCT/US2020/055053 filed October 9, 2020, each of which is incorporated in this specification in its entirety by reference. [00202] In an embodiment, the cellular receptor-binding moiety may include an asialoglycoprotein receptor (ASGPR) binding group connected through an amine group to the linker moiety. [00203] The amine group may be a primary alkyl amine group or secondary alkyl amine group, each of which is optionally substituted on the amine group with a C₁-C₃ alkyl group.

60 30124-WO-PCT [00204] The cellular receptor-binding moiety may include an ASGPR-binding group according to the chemical structure: , , wherein X is 1-4 atoms in length and comprises O, S, N(R^N1) or C(R^N1)(R^N1) groups such that: when X is 1 atom in length, X is O, S, N(R^N1) or C(R^N1)(R^N1), when X is 2 atoms in length, no more than 1 atom of X is O, S or N(R^N1), when X is 3 or 4 atoms in length, no more than 2 atoms of X are O, S or N(R^N1); wherein R^N1 is H or a C₁-C₃ alkyl group optionally substituted with from 1-3 halo groups; R₁ and R₃ are each independently: H, -(CH₂)_KOH, -(CH₂)_KOC₁-C₄ alkyl, which is optionally substituted with from 1-3 halo groups, C₁-C₄ alkyl, which is optionally substituted with from 1-3 halo groups, -(CH₂)_K-vinyl, O- (CH₂)_K-vinyl, -(CH₂)_K-alkynyl, -(CH₂)_K-COOH, -(CH₂)_KC(O)O-C₁-C₄ alkyl optionally substituted with from 1-3 halo groups, O-C(O)-C₁- C₄ alkyl, which is optionally substituted with from 1-3 halo groups, -C(O)-C₁-C₄ alkyl, which is optionally substituted with from 1-3 halo groups, or R₁ and R₃ are each independently group, which is optionally substituted with up to three halo groups, C₁-C₄ alkyl groups, each of which alkyl group is optionally substituted with from one to three halo groups or one or two hydroxyl groups, or O-C₁-C₄ alkyl groups,

61 30124-WO-PCT each of which alkyl groups is optionally substituted with from one to three halo groups or one or two hydroxyl groups; and K is independently an integer of 0 to 4, or R₁ and R₃ are each independently a group according to the chemical structure: , wherein R⁷ is O-C₁-C₄ alkyl, which is optionally substituted with from 1 to 3 halo groups 1 or 2 hydroxy groups, or R⁷ is a -NR^N3R^N4 group or a; or R₁ and R₃ are each independently a group according to the structure: ,

62 30124-WO-PCT ,

63 30124-WO-PCT ere roxyl groups, or a group according to the structure:

64 30124-WO-PCT

pendently, H, halo (F, Cl, Br, I), CN, NR^N1R^N2, -(CH₂)_KOH, -(CH₂)_KOC₁-C₄ alkyl, which is optionally substituted with from 1-3 halo groups, C₁-C₃ alkyl, which is optionally substituted with from 1-3 halo groups, -O-C₁-C₃-alkyl, which is optionally substituted with from 1-3 halo groups, -(CH₂)_KCOOH, -(CH₂)_KC(O)O-C₁-C₄ alkyl optionally substituted with from 1-3 halo groups, O-C(O)-C₁-C₄ alkyl, which is optionally substituted with from 1-3 halo groups, -C(O)-C₁-C₄ alkyl, which is optionally substituted with from 1-3 halo groups, or a group optionally substituted with from one to three halo groups or one or two hydroxyl groups; K is independently an integer of 0 to 4; K’ is an integer of 1 to 4; R^N3 is H, or a C₁-C₃ alkyl group optionally substituted with 1-3 halo groups or 1 or 2 hydroxy groups; and R^N4 is H, a C₁-C₃ alkyl group optionally substituted with 1-3 halo groups or 1 or 2 hydroxy groups, or R^N4 is a group, where K is preferably 1;

65 30124-WO-PCT is a linker group which comprises at least one anti-PLA2R antibody-binding moiety and links the at least one anti-PLA2R antibody-binding moiety to the cellular receptor-binding moiety through the optional linker moiety, or is a linker group which has at least one or more functional groups which can be used to covalently bond the linker group to at least one anti-PLA2R antibody-binding moiety or optional linker moiety; group wherein R^N1 and K are the same as above; substituted with up to 3 halo groups and one or two hydroxyl groups, a -(CH₂)_KCOOH group, a -(CH₂)_KC(O)O-C₁-C₄ alkyl group optionally substituted with from 1-3 halo groups, a O-C(O)-C₁-C₄ alkyl group, which is optionally substituted with from 1-3 halo F groups, a -C(O)-C₁-C₄ alkyl group, which is optionally substituted with from 1-3 halo groups, a -(CH₂)_K-NR^N3R^N4 group where R^N3 is H, or a C₁-C₃ alkyl group optionally substituted with 1-3 halo groups or 1 or 2 hydroxy groups; and R^N4 is H, a C₁-C₃ alkyl group optionally substituted with 1-3 halo groups or 1 or 2 hydroxy groups, or a group, or group, _KOC₁-C₄ alkyl, which is optionally substituted with from 1-3 halo groups, C₁-C₄ alkyl, which is optionally substituted with from 1-3 halo groups, -(CH₂)_KCOOH, -(CH₂)_KC(O)O-C₁-C₄ alkyl optionally substituted with from 1-3 halo groups, O- C(O)-C₁-C₄ alkyl, which is optionally substituted with from 1-3 halo groups, -C(O)-C₁-C₄ alkyl, which is optionally substituted with from 1-3 halo groups, or R^TA is a C₃-C₁₀ aryl or a three- to ten-membered heteroaryl group containing up to 5 heteroaryl atoms, each of said aryl or heteroaryl groups being optionally substituted with up to three (preferably 1) CN, NR^N1R^N2, -(CH₂)_KOH, -(CH₂)_KOC₁-C₄ alkyl, which is optionally substituted with from 1-3 halo groups, C₁-C₃ alkyl, which is optionally substituted with from 1-3 halo groups or 1 or 2 hydroxy

66 30124-WO-PCT groups, -O-C₁-C₃-alkyl, which is optionally substituted with from 1-3 halo groups, -(CH₂)_KCOOH, - (CH₂)_KC(O)O-C₁-C₄ alkyl optionally substituted with from 1-3 halo groups, O-C(O)-C₁-C₄ alkyl, which is optionally substituted with from 1-3 halo groups or -(CH2)KC(O)-C1-C4 alkyl optionally substituted with from 1-3 halo groups, or halo groups, or R^TA is a group, wherein R^N, R^N1 and R^N2 are each independently H or a C₁-C₃ alkyl group optionally substituted with from one to three halo groups or one or two hydroxyl groups and each -(CH₂)_K group is optionally substituted with 1-4, preferably 1 or 2, C₁-C₃ alkyl groups optionally substituted with from 1-3 fluoro groups or 1-2 hydroxyl groups; and K is independently 0-4. [00205] In an embodiment, X is -O-C(R^N1)(R^N1), C(R^N1)(R^N1)-O-, -S-C(R^N1)(R^N1), C(R^N1)(R^N1)-S-, N(R^N1)-C(R^N1)(R^N1), C(R^N1)(R^N1)-N(R^N1) or C(R^N1)(R^N1)-C(R^N1)(R^N1) when X is 2 atoms in length, X is -O-C(R^N1)(R^N1)-C(R^N1)(R^N1), C(R^N1)(R^N1)-O-C(R^N1)(R^N1)-, -O-C(R^N1) (R^N1)-O-, -O-C(R^N1) (R^N1)-S-, -O-C(R^N1) (R^N1)-N(R^N1)-, -S-C(R^N1)(R^N1)-C(R^N1)(R^N1), C(R^N1)(R^N1)-S-C(R^N1)(R^N1)-, C(R^N1)(R^N1)-C(R^N1)(R^N1)-S, -S-C(R^N1)(R^N1)-S- , -S-C(R^N1)(R^N1)-O-, -S-C(R^N1)(R^N1)-N(R^N1)-, N(R^N1)-C(R^N1)(R^N1)-C(R^N1)(R^N1), C(R^N1)(R^N1)-N(R^N1)-C(R^N1)(R^N1), C(R^N1)(R^N1)-C(R^N1)(R^N1)- N(R^N1), N(R^N1)-C(R^N1)(R^N1)-N(R^N1) or C(R^N1)(R^N1)-C(R^N1)(R^N1)- C(R^N1)(R^N1) when X is 3 atoms in length, and

67 30124-WO-PCT X is-O-C(R^N1)(R^N1)-C(R^N1)(R^N1)-C(R^N1)(R^N1), C(R^N1)(R^N1)-O-C(R^N1)(R^N1)-(R^N1)(R^N1)-, -O-C(R^N1)(R^N1)- O-C(R^N1)(R^N1)-, -S-C(R^N1)(R^N1)-C(R^N1)(R^N1)- C(R^N1)(R^N1)-, C(R^N1)(R^N1)-S-C(R^N1)(R^N1)-C(R^N1)(R^N1)-, C(R^N1)(R^N1)- (R^N1)(R^N1)-S-C(R^N1)(R^N1)-, -S-C(R^N1)(R^N1)-S-C(R^N1)(R^N1)-, N(R^N1)-C(R^N1)(R^N1)-C(R^N1)(R^N1)- C(R^N1)(R^N1)-, C(R^N1)(R^N1)-N(R^N1)-C(R^N1)(R^N1)-C(R^N1)(R^N1), C(R^N1)(R^N1)-C(R^N1)(R^N1)- N(R^N1), N(R^N1)-C(R^N1)(R^N1)-N(R^N1) or C(R^N1)(R^N1)-C(R^N1)(R^N1)- C(R^N1)(R^N1) when X is 4 atoms in length, wherein R^N1 is the same as stated in claim 4 or 6 above. [00206] In an embodiment, X is OCH₂ or CH₂O and R^N1 is H. [00207] The cellular receptor-binding moiety may include an ASGPR-binding group according to the chemical structure: , , where R₁, R₂ and R₃ are the same as in Claim 9, or a pharmaceutically acceptable salt, stereoisomer, solvate or polymorph thereof. [00208] The cellular receptor-binding moiety may have the following structure: ; 30124-WO-PCT where R^A is a C₁-C₃ alkyl group optionally substituted with 1-5 halo (preferably fluoro) groups (preferably R^A is a methyl or ethyl group optionally substituted with from 1-3 fluoro groups); ZA is -(CH2)IM, -O-(CH2)IM, S-(CH2)IM, NRM-(CH2)IM, C(O)-(CH2)IM-, a PEG group containing from 1 to 8 preferably 1-4 ethylene glycol residues or a -C(O)(CH₂)_IMNR_M group (preferably a PEG containing group comprising from 1 to 8 ethylene glycol, preferably 2-4 ethylene glycol residues) where IM and R_M are the same as above; and Z_B is absent, (CH₂)_IM, C(O)-(CH₂)_IM- or C(O)-(CH₂)_IM-NR_M, where IM and R_M are the same as above. [00209] In an embodiment, R^A may be a methyl or ethyl group optionally substituted with from 1-3 fluoro groups. In an embodiment, Z_A may be a PEG group containing from 1 to 4 ethylene glycol residues. In an embodiment, the methyl or ethyl group may be substituted with from 1-3 fluoro groups. In an embodiment, the ASGPR-binding group may be N-acetyl-D-galactosamine. In an embodiment, the cellular receptor-binding moiety may be a low-density lipoprotein receptor-related protein 1 (LRP1), a low-density lipoprotein receptor (LDLR), a FcγRI-binding group, a FcRN-binding group, a transferrin receptor-binding group, or a macrophage scavenger receptor-binding group. Methods of making several agents. [00210] Agents of this specification may be prepared or isolated by synthetic or semi-synthetic methods or recombinant methods under this specification. In some embodiments, polypeptide agents, e.g., cellular receptor-binding moiety peptide agents, maybe be prepared using biological expression systems. In some embodiments, provided agents are prepared synthetically. In some embodiments, provided agents are prepared using certain technologies described in WO2019/023501, which is incorporated in this specification in its entirety by reference. [00211] Several technologies, e.g., those for preparing antibody-drug conjugates, may be used in preparation of MATE agents. In many such technologies, conjugation is not selective regarding amino acid residue sites, and product compositions usually have several types of agents which may differ from each other regarding number of target-binding moieties conjugated or conjugation sites. In some embodiments, the invention provides technologies that can be used for selective conjugation of target- binding moieties at amino acid residue sites.

69 30124-WO-PCT [00212] In some embodiments, the invention provides a method of synthesis, comprising the steps of: contacting a first agent comprising a cellular receptor-binding moiety linked to a first reactive group optionally through a first linker with a second agent comprising an antibody moiety linked to a second reactive group optionally through a second linker, wherein the first reactive group reacts with a second reactive group, and forming a product agent comprising a cellular receptor-binding moiety and an antibody- binding moiety optionally through a linker. [00213] In some embodiments, the invention provides a method of synthesis, comprising the steps of: contacting a first composition comprising a plurality of first agents each independently comprising a cellular receptor-binding moiety linked to a first reactive group optionally through a first linker moiety with a second composition comprising a plurality of second agents each independently comprising an antibody moiety optionally linked to a second reactive group optionally through a second linker moiety, wherein a product composition comprising a plurality of product agents each independently comprising a cellular receptor-binding moiety and an antibody-binding moiety optionally through a linker is formed. MATES [00214] Persons having ordinary skill in the biomedical art can use MATES materials and methods as guidance to predictable results when making and using the invention. [00215] In some embodiments, the invention provides an agent comprising: an antibody moiety, a cellular receptor-binding moiety, and a linker moiety (optionally a single peptide linkage) linking an antibody moiety and a cellular receptor-binding moiety. [00216] This agent may be called a MATE agent or MATE. The MATE agents are described, for example, in International Application No. PCT/US2020/061127 filed November 18, 2020, the content of which is incorporated in this specification in its entirety by reference. In some embodiments, an agent comprises an antibody moiety, a cellular receptor-binding moiety, and a linker moiety linking an antibody moiety and a cellular receptor-binding moiety.

70 30124-WO-PCT [00217] In another embodiment, the anti-PLA2R antibody-binding moiety is an antibody, an antibody variant, or an antigen-binding fragment thereof. [00218] In another embodiment, the anti-PLA2R antibody-binding moiety is a full IgG antibody or nanobody wherein the heavy chain comprises the three CDR regions of the anti-PLA2R antibody-binding moiety. A full-length human sourced IgG can be native and have variable glycosylation. Plurality of agents. Second agent. [00219] In another embodiment, the invention provides a composition including the agent and at least one additional agent comprising a moiety capable of-binding to the antibody that forms the antibody moiety of the first compound. [00220] In some embodiments, a first composition is a composition comprising a first agent as described in this specification. In some embodiments, second agents independently comprise second reactive groups. In some embodiments, a second composition is a composition comprising a plurality of agents as described in this specification, wherein each cellular receptor-binding moiety is independently a reactive group as described in this specification. In some embodiments, a second composition is an antibody composition, wherein antibodies in the composition are not chemically changed. In some embodiments, a second composition is an IVIG preparation. In some embodiments, a product composition is a composition comprising a plurality of agents as described in this specification, wherein each cellular receptor-binding moiety is independently a cellular receptor-binding moiety as described in this specification. [00221] In some embodiments, a cellular receptor-binding moiety in a product agent is a cellular receptor-binding moiety in a first agent. In some embodiments, an antibody moiety in a product agent is an antibody moiety in a second agent. In some embodiments, a second agent is an antibody agent, e.g., a monoclonal antibody, an antibody in a polyclonal antibody, an antibody in an IVIG preparation, etc. In embodiments, a second reactive group is a function group of an amino acid residue, e.g., −NH2 of Lys, −SH of Cys, etc. In embodiments, a second reactive group is −NH2 of a Lys residue, e.g., of a residue selected from K246 and K248 of IgG1 heavy chain amino acid residues corresponding thereto, K251 and K253 of an IgG2 heavy chain and amino acid residues corresponding thereto, and K239 and K241 of a heavy chain and amino acid residues corresponding thereto. In some embodiments, the invention provides selective reactions at amino acid residues of antibody moieties. [00222] In some embodiments, a second reactive group is installed to an antibody moiety optionally through a linker. In some embodiments, a second reactive group is installed to an antibody moiety

71 30124-WO-PCT through a linker. In some embodiments, a second reactive group is selectively linked to certain location(s) of an antibody moiety, e.g., certain location(s) selected from K246 and K248 of IgG1 heavy chain amino acid residues corresponding thereto, K251 and K253 of an IgG2 heavy chain and amino acid residues corresponding thereto, and K239 and K241 of an anti-PLA2R antibody heavy chain and amino acid residues corresponding thereto. In some embodiments, the invention provides selective reactions at amino acid residues of antibody moieties. [00223] In some embodiments, the invention provides agents each independently comprising an antibody-binding moiety that binds to an antibody agent, a reactive group, a cellular receptor-binding moiety, and optionally one or more linker moieties linking such groups/moieties. In some embodiments, such agents are useful as reaction partners, e.g., first agents) for conjugating moieties of interest, e.g., target-binding moieties, reactive groups, e.g., second reactive groups) to agents comprising antibody moieties, e.g., second agents). In some embodiments, the invention provides agents for conjugating moieties of interest to antibody moieties in several agents or antibody agents, e.g., monoclonal antibody agents, polyclonal antibody agents, antibody agents of IVIG preparations, etc. In embodiments, provided agents each comprise a cellular receptor-binding moiety, a reactive group, an antibody-binding moiety, and optionally one or more linker moieties (linkers) linking such moieties. In some embodiments, an antibody-binding moiety is part of a leaving group released after contacting this agent, e.g., a first agent, with an antibody moiety, e.g., of a second agent, and reacting a reactive group of this agent, e.g., a first reactive group of a first agent, with a reactive group of an antibody moiety, e.g., a second reactive group of a second agent, such as −NH2 of a Lys residue of an antibody protein. In some embodiments, provided technologies can provide improved conjugation efficiency, high selectivity, or fewer steps (sometimes, single step) to conjugation product agents. In some embodiments, a provided agent, e.g., a first agent, is a composition of matter of formula AGN301 or a salt thereof: LG−RG−LRM−TBT, [AGN301] or a salt thereof, wherein: LG is a group comprising an antibody-binding moiety; RG is a reactive group; LRM is a linker; and TBT is a cellular receptor-binding moiety. [00224] In some embodiments, LG is or comprises an antibody-binding moiety as described in this specification, and a linker which links an antibody-binding moiety and RG.

72 30124-WO-PCT [00225] In some embodiments, LG is or comprises R^LG−L^LG−, wherein R^LG is or comprises an antibody- binding moiety, and L^LG is a linker moiety as described in this specification. In some embodiments, LG is ABT-L^LG−. In some embodiments, L^LG is −L^LG1−L^LG2−, wherein each of L^LG1 and L^LG2 is independently a linker moiety as described in this specification. In some embodiments, L^LG is −L^LG1−L^LG2−L^LG3−, wherein each of L^LG1, L^LG2 and L^LG3 is independently as linker moiety described in this specification. In some embodiments, L^LG is −L^LG1−L^LG2−L^LG3−L^LG4−, wherein each of L^LG1, L^LG2, L^LG3 and L^LG4 is independently a linker moiety as described in this specification. In some embodiments, L^LG1 is bonded to R^LG. In some embodiments, L^LG1 is bonded to cellular receptor-binding moiety. In some embodiments, L^LG is −L^LG1−, and a reactive group comprises L^LG2, L^LG3 and L^LG4. In some embodiments, L^LG is −L^LG1−L^LG2−, and a reactive group comprises L^LG3 and L^LG4. In some embodiments, L^LG is −L^LG1−L^LG2−L^LG3−, and a reactive group comprises L^LG4. In some embodiments, each of L^LG1, L^LG2, L^LG3 and L^LG4 is independently L. [00226] In some embodiments, antibody-binding moieties, LG, etc. are released after reactions, e.g., after first agents, e.g., wherein MOIs are target-binding moieties) react with second agents, e.g., which are antibody agents comprising reactive amino acid residues such as amino groups as second reactive groups or second agents comprising second reactive groups introduced to antibody agents), or after first agents, e.g., wherein MOIs are reactive groups such as second reactive groups) react with second agents which are antibody agents. In some embodiments, an antibody-binding moiety is released after a reaction. In some embodiments, LG is released after a reaction. In some embodiments, a leaving group is released as part of a compound having the structure of LG−H or a salt thereof. In some embodiments, an antibody-binding moiety is released as part of a compound having the structure of LG−H or a salt thereof. In some embodiments, LG is released as part of a compound having the structure of LG−H or a salt thereof. In some embodiments, a released compound has the structure of R^LG−L^LG1−L^LG2−L^LG3−L^LG4−H or a salt thereof. In some embodiments, an antibody-binding moiety is released as part of a compound having the structure of R^LG−L^LG1−L^LG2−L^LG3−L^LG4−H or a salt thereof. In some embodiments, an antibody- binding moiety is released as part of a compound having the structure of R^LG−L^LG1−L^LG2−L^LG3−L^LG4−H or a salt thereof, wherein R^LG is or comprises an antibody-binding moiety. In some embodiments, LG is released as part of a compound having the structure of R^LG−L^LG1−L^LG2−L^LG3−L^LG4−H or a salt thereof, wherein LG is R^LG−L^LG, and L^LG is −L^LG1−, −L^LG1−L^LG2−, −L^LG1−L^LG2−L^LG3−, or −L^LG1−L^LG2−L^LG3−L^LG4−. In some embodiments, LG is released as part of a compound having the structure of R^LG−L^LG1−L^LG2−L^LG3−L^LG4−H or a salt thereof, wherein LG is R^LG−L^LG1−. In some embodiments, LG is released as part of a compound having the structure of R^LG−L^LG1−L^LG2−L^LG3−L^LG4−H or a salt thereof, wherein LG is R^LG−L^LG1−L^LG2. In some embodiments, LG is released as part of a compound having the structure of R^LG−L^LG1−L^LG2−L^LG3−L^LG4−H or

73 30124-WO-PCT a salt thereof, wherein LG is R^LG−L^LG1−L^LG2−L^LG3. In some embodiments, LG is released as part of a compound having the structure of R^LG−L^LG1−L^LG2−L^LG3−L^LG4−H or a salt thereof, wherein LG is R^LG−L^LG1−L^LG2−L^LG3−L^LG4. [00227] In some embodiments, L is a covalent bond, or a bivalent optionally substituted, linear or branched C_1-100 group comprising one or more aliphatic moieties, aryl moieties, heteroaliphatic moieties each independently having 1-20 heteroatoms, heteroaromatic moieties each independently having 1-20 heteroatoms, or any combinations of any one or more of such moieties, wherein one or more methylene units of the group are optionally and independently replaced with C_1-6 alkylene, C_1-6 alkenylene, a bivalent C_1-6 heteroaliphatic group having 1-5 heteroatoms, , −Cy−, −C(R’)₂−, −O−, −S−, −S−S−, −N(R’)−, −C(O)−, −C(S)−, −C(NR’)−, −C(O)N(R’)−, −C(O)C(R’)₂N(R’)−, −N(R’)C(O)N(R’)−, −N(R’)C(O)O−, −S(O)−, −S(O)₂−, −S(O)₂N(R’)−, −C(O)S−, −C(O)O−, −P(O)(OR’)−, −P(O)(SR’)−, −P(O)(R’)−, −P(O)(NR’)−, −P(S)(OR’)−, −P(S)(SR’)−, −P(S)(R’)−, −P(S)(NR’)−, −P(R’)−, −P(OR’)−, −P(SR’)−, −P(NR’)−, an amino acid residue, or −[(−O−C(R’)₂−C(R’)₂−)_n]−, wherein n is 1-20. In some embodiments, L is a covalent bond, or a bivalent optionally substituted, linear or branched C_1-100 aliphatic or heteroaliphatic group 1- 20 heteroatoms, wherein one or more methylene units of the group are optionally and independently replaced with , −Cy−, −C(R’)₂−, −O−, −S−, −S−S−, −N(R’)−, −C(O)−, −C(S)−, −C(NR’)−, −C(O)N(R’)−, −C(O)C(R’)2N(R’)−, −N(R’)C(O)N(R’)−, −N(R’)C(O)O−, −S(O)−, −S(O)2−, −S(O)2N(R’)−, −C(O)S−, −C(O)O−, −P(O)(OR’)−, −P(O)(SR’)−, −P(O)(R’)−, −P(O)(NR’)−, −P(S)(OR’)−, −P(S)(SR’)−, −P(S)(R’)−, −P(S)(NR’)−, −P(R’)−, −P(OR’)−, −P(SR’)−, −P(NR’)−, or −[(−O−C(R’)₂−C(R’)₂−)_n]−, wherein n is 1-20. In some embodiments, L is a covalent bond, or a bivalent optionally substituted, linear or branched C₁, C₂, C₃, C₄, C₅, C₁₀, C₁₅, C₂₀, C₂₅, C₃₀, C₄₀, C₅₀, C₆₀, C_1-2, C_1-5, C_1-10, C_1-15, C_1-20, C_1-30, C_1-40, C_1-50, C_1-60, C_1-70, C_1-80, or C_1-90 aliphatic or heteroaliphatic group 1-10 heteroatoms, wherein one or more methylene units of the group are optionally and independently replaced with , −Cy−, −C(R’)₂−, −O−, −S−, −S−S−, −N(R’)−, −C(O)−, −C(S)−, −C(NR’)−, −C(O)N(R’)−, −C(O)C(R’)₂N(R’)−, −N(R’)C(O)N(R’)−, −N(R’)C(O)O−, −S(O)−, −S(O)₂−, −S(O)₂N(R’)−, −C(O)S−, −C(O)O−, −P(O)(OR’)−, −P(O)(SR’)−, −P(O)(R’)−, −P(O)(NR’)−, −P(S)(OR’)−, −P(S)(SR’)−, −P(S)(R’)−, −P(S)(NR’)−, −P(R’)−, −P(OR’)−, −P(SR’)−, −P(NR’)−, amino acid residues, or −[(−O−C(R’)₂−C(R’)₂−)_n]−, wherein n is 1-20. In some embodiments, L is a covalent bond, or a bivalent optionally substituted, linear or branched C₁, C₂, C₃, C₄, C₅, C₁₀, C₁₅, C₂₀, C₂₅, C₃₀, C₄₀, C₅₀, C₆₀, C_1-2, C_1-5, C_1- ₁₀, C_1-15, C_1-20, C_1-30, C_1-40, C_1-50, C_1-60, C_1-70, C_1-80, or C_1-90 aliphatic or heteroaliphatic group 1-10 heteroatoms, wherein one or more methylene units of the group are optionally and independently replaced with −C≡C−, −Cy−, −C(R’)2−, −O−, −S−, −S−S−, −N(R’)−, −C(O)−, −C(S)−, −C(NR’)−, −C(O)N(R’)−, −C(O)C(R’)₂N(R’)−, −N(R’)C(O)N(R’)−, −N(R’)C(O)O−, −S(O)−, −S(O)₂−, −S(O)₂N(R’)−, −C(O)S−, −C(O)O−,

74 30124-WO-PCT amino acid residues, or −[(−O−C(R’)₂−C(R’)₂−)_n]−, wherein n is 1-10. In some embodiments, L is a covalent bond, or a bivalent optionally substituted, linear or branched C₁, C₂, C₃, C₄, C₅, C₁₀, C₁₅, C₂₀, C₂₅, C30, C40, C50, C60, C1-2, C1-5, C1-10, C1-15, C1-20, C1-30, C1-40, C1-50, C1-60, C1-70, C1-80, or C1-90 aliphatic group, wherein one or more methylene units of the group are optionally and independently replaced with −O−, −N(R’)−, −C(O)−, −C(O)N(R’)−, −C(O)C(R’)₂N(R’)−, −N(R’)C(O)N(R’)−, −N(R’)C(O)O−, −S(O)−, −S(O)₂−, −S(O)₂N(R’)−, amino acid residues, or −[(−O−C(R’)₂−C(R’)₂−)_n]−, wherein n is 1-10. In some embodiments, L is a covalent bond, or a bivalent optionally substituted, linear or branched C₁, C₂, C₃, C₄, C₅, C₁₀, C₁₅, C₂₀, C₂₅, C₃₀, C₄₀, C₅₀, C₆₀, C_1-2, C_1-5, C_1-10, C_1-15, C_1-20, C_1-30, C_1-40, C_1-50, C_1-60, C_1-70, C_1-80, or C_1-90 aliphatic group, wherein one or more methylene units of the group are optionally and independently replaced with −O−, −N(R’)−, −C(O)−, −C(O)N(R’)−, −C(O)C(R’)₂N(R’)−, −N(R’)C(O)N(R’)−, −N(R’)C(O)O−, −S(O)−, −S(O)₂−, −S(O)₂N(R’)−, or −[(−O−C(R’)₂−C(R’)₂−)_n]−, wherein n is 1-10. In some embodiments, L is a covalent bond, or a bivalent optionally substituted, linear or branched C_1-10 aliphatic group, wherein one or more methylene units of the group are optionally and independently replaced with −O−, −N(R’)−, −C(O)−, −C(O)N(R’)−, −C(O)C(R’)₂N(R’)−, −N(R’)C(O)N(R’)−, −N(R’)C(O)O−, −S(O)−, −S(O)₂−, −S(O)₂N(R’)−, −Cy−, or −[(−O−C(R’)₂−C(R’)₂−)_n]−, wherein n is 1-10. In some embodiments, L is a covalent bond, or a bivalent optionally substituted, linear or branched C_1-10 aliphatic group, wherein one or more methylene units of the group are optionally and independently replaced with −O−, −N(R’)−, −C(O)−, −C(O)N(R’)−, −C(O)C(R’)₂N(R’)−, −N(R’)C(O)N(R’)−, −N(R’)C(O)O−, −S(O)−, −S(O)₂−, −S(O)₂N(R’)−, or −[(−O−C(R’)₂−C(R’)₂−)_n]−, wherein n is 1-10. In some embodiments, L comprises no −C(O)O−. In some embodiments, L comprises no −C(O)−N(R’)−. In some embodiments, L comprises no −S−. In some embodiments, L comprises no −S−Cy−. In some embodiments, L comprises no −S−S−. In some embodiments, L does not have one or more or any of −C(O)O−, −C(O)−N(R’)−, −S−, and −S−S−. In some embodiments, L does not have one or more or any of −C(O)O−, −C(O)−N(R’)−, −S−Cy−, and −S−S−. In some embodiments, L does not have one or more or any of −C(O)O−, −S−, and −S−S−. In some embodiments, L does not have one or more or any of −C(O)O−, −S−Cy−, and −S−S−. In some embodiments, L has none of −C(O)O−, −S−, and −S−S−. In some embodiments, L has none of −C(O)O−, −S−Cy−, and −S−S−. In some embodiments, L has none of −C(O)O− and −S−S−. [00228] In some embodiments, L is a covalent bond. In some embodiments, L is not a covalent bond. [00229] In some embodiments, L^LG1 is a covalent bond. In some embodiments, L^LG1 is not a covalent bond. In some embodiments, L^LG1 is or comprises −(CH₂CH₂O)n−. In some embodiments, L^LG1 is or comprises a moiety selected from the Markush group of moieties consisting of −(CH₂)n−O−(CH₂CH₂O)n−(CH₂)n−, wherein each n is independently as described in this specification, and

75 30124-WO-PCT each −CH₂− is independently optionally substituted, −(CH₂)n−O−(CH₂CH₂O)n−(CH₂)n−, wherein each n is independently as described in this specification, and each −CH₂− is independently optionally substituted, −(CH2)2−O−(CH2CH2O)n−(CH2)2−, wherein n is as described in this specification, and each −CH2− is independently optionally substituted, and −(CH₂)₂−O−(CH₂CH₂O)n−(CH₂)₂−, wherein n is as described in this specification. [00230] In some embodiments, L^LG1 is a moiety selected from the Markush group of moieties consisting of L^LG1 is −CH₂−, −(CH₂)₂−, −(CH₂)₂−C(O)−, −(CH₂)₂−C(O)−NH−, −(CH₂)₃−, −(CH₂)₃NH−, −(CH₂)₃NH−C(O)−, −C(O)−(CH₂)₃NH−C(O)−, −C(O)−(CH₂)₃−, −NH−C(O)−(CH₂)₃−, and −NHC(O)−(CH₂)₃NH−C(O)−. In some embodiments, a −CH₂− is bonded to an antibody-binding moiety. [00231] In some embodiments, L^LG1 is a moiety selected from the Markush group of moieties consisting of −CH₂CH₂−O−CH₂CH₂−O−CH₂CH₂−, −CH₂CH₂−O−CH₂CH₂−O−CH₂CH₂−C(O)−, −CH₂CH₂−O−CH₂CH₂−O−CH₂CH₂−C(O)NH−, and −CH₂CH₂−O−CH₂CH₂−O−CH₂CH₂−C(O)NH−CH₂−. In some embodiments, −CH₂CH₂− is bonded to an antibody-binding moiety. [00232] In some embodiments, L^LG1 is −(CH₂CH₂O)n−. In some embodiments, L^LG1 is −(CH₂CH₂O)n−CH₂−CH₂−. In some embodiments, L^LG1 is −(CH₂CH₂O)n−CH₂−CH₂−C(O)−. In some embodiments, L^LG1 is −(CH₂CH₂O)₂−CH₂−CH₂−C(O)−. In some embodiments, L^LG1 is −(CH2CH2O)4−CH2−CH2−C(O)−. In some embodiments, L^LG1 is −(CH2CH2O)8−CH2−CH2−C(O)−. In some embodiments, −C(O)− is bonded to an antibody-binding moiety. [00233] In some embodiments, L^LG1 is −N(R’)−. In some embodiments, L^LG1 is −NH−. In some embodiments, L^LG1 is −NH−[(−CH₂CH₂−O−)]n−. In some embodiments, L^LG1 is −NH−[(−CH₂CH₂−O−)]n−CH₂CH₂−. In some embodiments, L^LG1 is −NH−[(−CH₂CH₂−O−)]n−CH₂CH₂−NH−. In some embodiments, L^LG1 is −NH−[(−CH₂CH₂−O−)]n−CH₂CH₂−NH−C(O)−. In some embodiments, n is 1. In some embodiments, n is 2. In some embodiments, n is 3. In some embodiments, n is 4. In some embodiments, n is 5. In some embodiments, L^LG1 is −NH−CH₂CH₂−O−. In some embodiments, L^LG1 is −NH−CH₂CH₂−O− CH₂CH₂−. In some embodiments, L^LG1 is −NH−CH₂CH₂−O− CH₂CH₂−NH−. In some embodiments, L^LG1 is −NH−CH₂CH₂−O− CH₂CH₂−NH−C(O)−. [00234] In some embodiments, L^LG1 is −NH−[(−CH₂CH₂−O−)]₂−. In some embodiments, L^LG1 is −NH−[(−CH₂CH₂−O−)]₂−CH₂CH₂−. In some embodiments, L^LG1 is −NH−[(−CH₂CH₂−O−)]₂−CH₂CH₂−NH−. In some embodiments, L^LG1 is −NH−[(−CH₂CH₂−O−)]₂−CH₂CH₂−NH−C(O)−. [00235] In some embodiments, L^LG1 is −NH−[(−CH₂CH₂−O−)]₃−. In some embodiments, L^LG1 is −NH−[(−CH2CH2−O−)]3−CH2CH2−. In some embodiments, L^LG1 is −NH−[(−CH2CH2−O−)]3−CH2CH2−NH−. In some embodiments, L^LG1 is −NH−[(−CH₂CH₂−O−)]₃−CH₂CH₂−NH−C(O)−. In some embodiments, L^LG1 is

76 30124-WO-PCT −NH−[(−CH₂CH₂−O−)]₄−. In some embodiments, L^LG1 is −NH−[(−CH₂CH₂−O−)]₄−CH₂CH₂−. In some embodiments, L^LG1 is −NH−[(−CH₂CH₂−O−)]₄−CH₂CH₂−NH−. In some embodiments, L^LG1 is −NH−[(−CH2CH2−O−)]4−CH2CH2−NH−C(O)−. In some embodiments, L^LG1 is −NH−[(−CH2CH2−O−)]5−. In some embodiments, L^LG1 is −NH−[(−CH₂CH₂−O−)]₅−CH₂CH₂−. In some embodiments, L^LG1 is −NH−[(−CH₂CH₂−O−)]₅−CH₂CH₂−NH−. In some embodiments, L^LG1 is −NH−[(−CH₂CH₂−O−)]₅−CH₂CH₂−NH−C(O)−. In some embodiments, −NH− is bonded to an antibody- binding moiety. [00236] In some embodiments, L^LG1 is −CH₂−. In some embodiments, L^LG1 is −CH₂CH₂−. In some embodiments, L^LG1 is −CH₂CH₂NH−. In some embodiments, L^LG1 is −CH₂CH₂NH−(CO)−. In some embodiments, −CH₂− is bonded to an antibody-binding moiety. [00237] In some embodiments, L^LG1 is −CH₂−. In some embodiments, L^LG1 is −CH₂C(O)−. In some embodiments, L^LG1 is −CH₂C(O)NH−. In some embodiments, L^LG1 is −CH₂(CO)NHCH₂−. In some embodiments, −CH₂−C(O)− is bonded to an antibody-binding moiety at −CH₂−. [00238] In some embodiments, L^LG2 is a covalent bond. In some embodiments, L^LG2 is not a covalent bond. In some embodiments, L^LG2 is −N(R’)C(O)−. In some embodiments, L^LG2 is −NHC(O)−. In some embodiments, L^LG2 is −(CH₂)n−N(R’)C(O)−, wherein −(CH₂)n− is optionally substituted. In some embodiments, L^LG2 is −(CH2)n−OC(O)−, wherein −(CH2)n− is optionally substituted. In some embodiments, L^LG2 is −(CH₂)n−OC(O)N(R’)−, wherein −(CH₂)n− is optionally substituted. In some embodiments, L^LG2 is −(CH₂)n−OC(O)NH−, wherein −(CH₂)n− is optionally substituted. In some embodiments, n is 1-10, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. In some embodiments, n is 1. In some embodiments, n is 2. In some embodiments, n is 3. In some embodiments, −(CH₂)n− is substituted. In some embodiments, −(CH₂)n− is unsubstituted. In some embodiments, L^LG2 is −CH₂N(CH₂CH₂CH₂S(O)₂OH)−C(O)−. In some embodiments, L^LG2 is −C(O)−NHCH₂−. In some embodiments, L^LG2 is −C(O)−NHCH₂CH₂−. In some embodiments, L^LG2 is −C(O)O−CH₂−. In some embodiments, L^LG2 is −NH−C(O)O−CH₂−. In some embodiments, −C(O)− is bonded to L^LG3. In some embodiments, −N(R’)−, −NH−, or an optionally substituted −CH₂− unit (of optionally substituted −(CH₂)n−) is bonded to L^LG3. In some embodiments L^LG2 is −NH−, −NHC(O)−,−(CH₂)n−NHC(O)−, −(CH₂)n−OC(O)−, −(CH₂)n−OC(O)NH−, −C(O)−NHCH₂−, −C(O)−NHCH₂CH₂−, −C(O)O−CH₂−, or −NH−C(O)O−CH₂−. [00239] In some embodiments, L^LG2 is −N(R’)−. In some embodiments, L^LG2 is −N(R)−. In some embodiments, L^LG2 is −NH−.

77 30124-WO-PCT [00240] In some embodiments, L^LG2 is optionally substituted bivalent C_1-6 aliphatic. In some embodiments, L^LG2 is −CH₂−. In some embodiments, L^LG2 is −CH₂NH−. In some embodiments, L^LG2 is −CH2NH−C(O)−. In some embodiments, L^LG2 is −CH2NH−C(O)−CH2−. [00241] In some embodiments, L^LG3 is or comprises an optionally substituted aryl ring. In some embodiments, L^LG3 is or comprises an optionally substituted phenyl ring. In some embodiments, L^LG3 is a phenyl ring substituted with one or more electron-withdrawing groups. As understood by persons having ordinary skill in the biomedical art, several electron-withdrawing groups are known in the biomedical art and may be used under this specification. In some embodiments, an electron- withdrawing group is halogen. In some embodiments, an electron-withdrawing group is −F. In embodiments, it is −Cl. In some embodiments, it is −Br. In embodiments, it is −I. In embodiments, an electron-withdrawing group comprises an X=Y double bond, wherein X is bonded to the group to which the electron-withdrawing group is a substituent, and at least one of X and Y is a heteroatom. In some embodiments, X is a heteroatom. In some embodiments, Y is a heteroatom. In some embodiments, each of X and Y is independently a heteroatom. In some embodiments, Y is O. In embodiments, Y is S. In embodiments, X is C. In embodiments, X is N. In embodiments, X is P. In embodiments, X is S. In embodiments, X=Y is C=O. In embodiments, X=Y is N=O. In embodiments, X=Y is S=O. In embodiments, X=Y is P=O. In embodiments, an electron-withdrawing group is −C(O)−L−R’. In some embodiments, an electron-withdrawing group is −C(O)−R’. In some embodiments, it is −NO₂. In some embodiments, it is −S(O)−L−R’. In some embodiments, it is −S(O)−R’. In some embodiments, it is −S(O)₂−L−R’. In some embodiments, it is −S(O)₂−O−R’. In some embodiments, it is −S(O)₂−N(R’)₂. In some embodiments, it is −P(O)(−L−R’)₂. In some embodiments, it is −P(O)(R’)₂. In some embodiments, it is −P(O)(OR’)₂. In some embodiments, it is −P(O)[N(R’)₂]₂. [00242] In some embodiments, L^LG3 is −L^LG3a−L^LG3b−, wherein L^LG3a is a covalent bond or −C(O)O−CH₂−, wherein −CH₂− is optionally substituted, and L^LG3b is an optionally substituted aryl ring. In some embodiments, L^LG3a is bonded to L^LG2, and L^LG3b is bonded to L^LG4. [00243] In some embodiments, L^LG3a is a covalent bond. In some embodiments, L^LG3a is −C(O)O−CH₂−, wherein −CH₂− is optionally substituted. In some embodiments, L^LG3a is −C(O)O−CH₂−, wherein −CH₂− is substituted. In some embodiments, L^LG3a is −C(O)O−CH₂−, wherein −CH₂− is unsubstituted. [00244] In some embodiments, a first group, an antibody-binding moiety, or LG is released as part of a compound having the structure of R^LG−L^LG1−L^LG2−H or a salt thereof. [00245] In some embodiments, L^LG3b is an optionally substituted phenyl ring. In some embodiments, at least one substituent is an electron-withdrawing group as described in this specification.

78 30124-WO-PCT [00246] In some embodiments, L^LG3 i , wherein s is 0-4, each R^s is independently halogen, −NO₂, −L−R’, −C(O)−L−R’, −S(O) ₂−L−R’, or −P(O)(−L−R’)₂. In some embodiments, C1 is bonded to L^LG4. In some embodiments, L^LG3 is . In some embodiments, L^LG3 is . In some In some . In some embodiments, L^LG3 . In some embodiments, L^LG3 . [00247] In some embodiments, L^LG3b , wherein s is 0-4, each R^s is independently halogen, −NO₂, −L−R’, −C(O)−L−R’, −S(O) or −P(O)(−L−R’)₂. In some embodiments, C1 is bonded to L^LG4. In some embodiments, L^LG3b is . In some embodiments, L^LG3b is . In some embodiments, In some . In some embodiments, L^LG3b . In some embodiments, L^LG3b . [00248] In some some embodiments, s is 1-4. s is 1. In some embodiments, s is 2. In some embodiments, s is 3. In some embodiments, s is 4. [00249] In some embodiments, s is 1-4, and at least one R^s is an electron-withdrawing group, e.g., an electron-withdrawing group described above. In some embodiments, at least one R^s is −NO₂. In some embodiments, at least one R^s is −F. In embodiments, each R^s is independently an electron-withdrawing group. In some embodiments, each R^s is −NO₂. In some embodiments, each R^s is −F.

79 30124-WO-PCT [00250] In some embodiments, an electron-withdrawing group or R^s is at C2. In some embodiments, an electron-withdrawing group or R^s is at C3. In some embodiments, an electron-withdrawing group or R^s is at C4. In some embodiments, an electron-withdrawing group or R^s is at C2 and C5. [00251] In some . In some . In some [00253] In some embodiments, L^LG3b is optionally In some embodiments, the nitrogen atom is bound to L^LG4 which is −O−. In some atom is bound to L^LG4 which is −O−, and −L^RG1−L^RG2− is −C(O)−.

80 30124-WO-PCT [00254] In some embodiments, −L^LG4−L^RG1−L^RG2− is −O−C(O)−. In some embodiments, −L^LG4−L^RG1−L^RG2− is −S−C(O)−. [00255] In some embodiments, L^LG4 is a covalent bond. In some embodiments, L^LG4 is not a covalent bond. In some embodiments, L^LG4 is −O−. In some embodiments, L^LG4 is −N(R’)−. In some embodiments, L^LG4 is −NH−. In some embodiments, L^LG4 is −N(CH₃)−. In some embodiments, L^LG4 is −N(R’)−, and L^LG3 is −O−. In some embodiments, R’ is optionally substituted C_1-6 alkyl. In some embodiments, L^LG4 is −S−. [00256] In some embodiments, R^LG is or comprises an antibody-binding moiety. In some embodiments, R^LG is or comprises a protein-binding moiety. In some embodiments, R^LG is or comprises an antibody-binding moiety. In some embodiments, R^LG is an antibody-binding moiety. In some embodiments, R^LG is a protein-binding moiety. In some embodiments, R^LG is an antibody-binding moiety. [00257] In some embodiments, R^LG is ABT101, R^c−(Xaa)z−, a nucleic acid moiety, or a small molecule moiety. In some embodiments, R^LG is or comprises ABT101. In some embodiments, R^LG is or comprises Rc−(Xaa)z−. In some embodiments, R^LG is or comprises a small molecule moiety. In some embodiments, R^LG is or comprises a peptide agent. In some embodiments, R^LG is or comprises a nucleic acid agent. In some embodiments, R^LG is or comprises an aptamer agent. In some embodiments, an antibody-binding moiety is or comprises ABT101. In some embodiments, a protein-binding moiety is or comprises ABT101. In some embodiments, an antibody-binding moiety is or comprises ABT101. In some embodiments, an antibody-binding moiety is or comprises Rc−(Xaa)z−. In some embodiments, a protein- binding moiety is or comprises Rc−(Xaa)z−. In some embodiments, an antibody-binding moiety is or comprises Rc−(Xaa)z−. [00258] In some embodiments, target-binding moieties may be conjugated to antibody moieties optionally through linker moieties using technologies described in US 2020/0190165. [00259] In some embodiments, where a particular protecting group (PG), leaving group (LG), or transformation condition is depicted, persons having ordinary skill in the biomedical art know that other protecting groups, leaving groups, and transformation conditions are also suitable and are contemplated. Such groups and transformations are described in Smith & March, March's Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, 5^th edition (John Wiley & Sons, 2001), Larock, Comprehensive Organic Transformations, 2^nd edition (John Wiley & Sons, 1999), and Greene & Wuts, Protecting Groups in Organic Synthesis, 3^rd edition (John Wiley & Sons, 1999), the entirety of each of which is incorporated in this specification by reference.

81 30124-WO-PCT [00260] In some embodiments, leaving groups include but are not limited to, halogens, e.g. fluoride, chloride, bromide, iodide, sulfonates, e.g. mesylate, tosylate, benzenesulfonate, brosylate, nosylate, triflate), diazonium. [00261] In some embodiments, an oxygen protecting group includes carbonyl protecting groups, hydroxyl protecting groups, etc. Hydroxyl protecting groups are well known in the biomedical art and include those described in Greene & Wuts, Protecting Groups in Organic Synthesis, 3^rd edition (John Wiley & Sons, 1999), the entirety of which is incorporated in this specification by reference. Examples of suitable hydroxyl protecting groups include, but are not limited to, esters, allyl ethers, ethers, silyl ethers, alkyl ethers, arylalkyl ethers, and alkoxyalkyl ethers. Examples of such esters include formates, acetates, carbonates, and sulfonates. Specific examples include formate, benzoyl formate, chloroacetate, trifluoroacetate, methoxyacetate, triphenylmethoxyacetate, p-chlorophenoxyacetate, 3- phenylpropionate, 4-oxopentanoate, 4,4-(ethylenedithio)pentanoate, pivaloate (trimethylacetyl), crotonate, 4-methoxy-crotonate, benzoate, p-benylbenzoate, 2,4,6-trimethylbenzoate, carbonates such as methyl, 9-fluorenylmethyl, ethyl, 2,2,2-trichloroethyl, 2-(trimethylsilyl)ethyl, 2-(phenylsulfonyl)ethyl, vinyl, allyl, and p-nitrobenzyl. Examples of such silyl ethers include trimethylsilyl, triethylsilyl, t- butyldimethylsilyl, t-butyldiphenylsilyl, triisopropylsilyl, and other trialkylsilyl ethers. Alkyl ethers include methyl, benzyl, p-methoxybenzyl, 3,4-dimethoxybenzyl, trityl, t-butyl, allyl, and allyloxycarbonyl ethers or derivatives. Alkoxyalkyl ethers include acetals such as methoxymethyl, methylthiomethyl, (2- methoxyethoxy)methyl, benzyloxymethyl, beta-(trimethylsilyl)ethoxymethyl, and tetrahydropyranyl ethers. Examples of arylalkyl ethers include benzyl, p-methoxybenzyl (MPM), 3,4-dimethoxybenzyl, O- nitrobenzyl, p-nitrobenzyl, p-halobenzyl, 2,6-dichlorobenzyl, p-cyanobenzyl, and 2- and 4-picolyl. [00262] Amino protecting groups are well known in the biomedical art and include those described in Greene & Wuts, Protecting Groups in Organic Synthesis, 3^rd edition (John Wiley & Sons, 1999), the entirety of which is incorporated in this specification by reference. Suitable amino protecting groups include, but are not limited to, aralkylamines, carbamates, cyclic imides, allyl amines, amides. Examples of such groups include t-butyloxycarbonyl (BOC), ethyloxycarbonyl, methyloxycarbonyl, trichloroethyloxycarbonyl, allyloxycarbonyl (Alloc), benzyloxocarbonyl (CBZ), allyl, phthalimide, benzyl (Bn), fluorenylmethylcarbonyl (Fmoc), formyl, acetyl, chloroacetyl, dichloroacetyl, trichloroacetyl, phenylacetyl, trifluoroacetyl, benzoyl. [00263] Persons having ordinary skill in the biomedical art know that provided agents may have one or more stereocenters and may be present as a racemic or diastereomeric mixture. Persons having ordinary skill in the biomedical art know there are many methods known in the biomedical art for the

82 30124-WO-PCT separation of isomers to obtain stereoenriched or stereopure isomers of those compounds, including but not limited to HPLC, chiral HPLC, fractional crystallization of diastereomeric salts, kinetic enzymatic resolution, e.g. by fungal- derived, bacterial- derived, or animal-derived lipases or esterases, and formation of covalent diastereomeric derivatives using an enantioenriched reagent. [00264] persons having ordinary skill in the biomedical art know that several functional groups present in compounds of this specification such as aliphatic groups, alcohols, carboxylic acids, esters, amides, aldehydes, halogens, and nitriles can be interconverted by techniques well known in the biomedical art including, but not limited to reduction, oxidation, esterification, hydrolysis, partial oxidation, partial reduction, halogenation, dehydration, partial hydration, and hydration. See Smith & March, March's Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, 5^th edition (John Wiley & Sons, 2001), the entirety of which is incorporated in this specification by reference. Such interconversions may require one or more techniques, and certain methods for synthesizing compounds of this specification are described below in the Exemplification. [00265] As known by persons having ordinary skill in the biomedical art, reaction partners are generally contacted with each other under conditions and for a time sufficient for production of the desired results, e.g., formation of product agents and compositions thereof to desired extents. Many reaction conditions/reaction times may be assessed and used if they are suitable for desired purposes under this specification; certain such conditions, reaction times, assessment, etc. are described in the Examples. [00266] In some embodiments, an agent formed, e.g., a product MATE agent, has the structure of formula AGN101 or AGN102, or a salt thereof. In some embodiments, a cellular receptor-binding moiety in a product agent, e.g., a MATE agent, is the same as a cellular receptor-binding moiety in a reaction partner, e.g., a first agent comprising a cellular receptor-binding moiety) used to prepare a product agent. In some embodiments, an antibody moiety in a product agent, e.g., a MATE agent, is the same as an antibody moiety in a reaction partner, e.g., a second agent comprising an antibody moiety) used to prepare a product agent. [00267] In some embodiments, linker moieties or a part connected to target-binding moieties or antibody moieties may be transferred from reaction partners, e.g., L^RM of formula AGN301 or a salt thereof. In some embodiments, a linker moiety in a product agent (may be called L^PM; e.g., L in formula AGN101 or AGN102, is or comprises a linker moiety in a reaction partner, e.g., one between a reactive group and a cellular receptor-binding moiety, e.g., L^RM. In some embodiments, L^PM is or comprises L^RM. In some embodiments, L^PM is −L^RM−L^RG2−. In some embodiments, L^RG2 is −C(O)−. In some embodiments, L^RG2

83 30124-WO-PCT is −C(O)−, and is bonded to −NH− of a target agent moiety, e.g., −NH− in a side chain of a lysine residue of a protein moiety, which in some embodiments, is an antibody moiety. [00268] Reaction partners, e.g., compounds of formula AGN301 or salts thereof, rarely have moieties that can react with reactive groups under conditions under which reactive groups react with target agents. In some embodiments, to the extent that some moieties in reaction partners may react with reactive groups under conditions under which reactive groups react with target agents, reactions between such moieties and reactive groups are significantly slower or less efficient compared to reactions between reactive groups and target agents. In some embodiments, reactions between such moieties and reactive groups do not significantly reduce, e.g., no more than about 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, etc. of reduction, efficiencies, yields, rates, or conversions, etc., of reactions between reactive groups and target agents. In some embodiments, reactive groups, e.g., ester groups, activated carboxylic acid derivatives, etc. react with amino groups, e.g., −NH₂ groups, of target agents, e.g., protein agents such as antibody agents. In some embodiments, reaction partners, e.g., compounds of formula AGN301 or salts thereof, do not have amine groups. In some embodiments, compounds of formula AGN301 or salts thereof (or parts of it, such as R^LG, L^LG, L^LG1, L^LG2, L^LG3, L^LG4, L^RG1, L^RG2, L^RM, or MOI, do not have amine groups. In some embodiments, they do not have primary amine groups (−NH2). In some embodiments, they do not have −CH2NH2. In some embodiments, they do not have −CH₂CH₂NH₂. In some embodiments, they do not have −CH₂CH₂CH₂NH₂. In some embodiments, they do not have −CH₂CH₂CH₂CH₂NH₂. In some embodiments, amine groups, e.g., primary amine groups, are capped, e.g., by introduction of acyl groups, e.g., R−C(O)−, e.g., acetyl to form amide groups) to prevent or reduce undesired reactions. [00269] In some embodiments, reactions are performed in buffer systems. In some embodiments, buffer systems of present disclosure maintain structures or functions of target agents, cellular receptor- binding moiety, etc. In embodiments, a buffer is a phosphate buffer. In some embodiments, a buffer is a phosphate-buffered saline (PBS) buffer. In some embodiments, a buffer is a borate buffer. In some embodiments, buffers of this specification provide and optionally maintain certain pH value or range. In some embodiments, a useful pH is about 7-9, e.g., 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 9.0, etc. In embodiments, a pH is 7.4. In some embodiments, a pH is 7.5. In some embodiments, a pH is 7.8. In some embodiments, a pH is 8.0. In some embodiments, a pH is 8.2. In some embodiments, a pH is 8.3. [00270] Provided technologies can provide several advantages. In some embodiments, connection of a cellular receptor-binding moiety in a reaction partner, e.g., a compound comprising a reactive group

84 30124-WO-PCT between an antibody-binding moiety and a cellular receptor-binding moiety, e.g., a composition of matter of formula AGN301 or a salt thereof to an agent comprising an antibody moiety, e.g., a second agent such as an antibody agent, and release of an antibody-binding moiety in a provided reaction partner can be achieved in one reaction or in one pot. In many embodiments, no separate reactions/steps are performed to remove antibody-binding moieties. As known by persons having ordinary skill in the biomedical art, by performing connection of cellular receptor-binding moiety and release of antibody-binding moiety in a single reaction/operation, provided technologies can avoid separate steps for antibody-binding moiety removal and can improve overall efficiency, e.g., by simplify operations, increasing overall yield, etc. , reduce manufacturing cost, improve product purity, e.g., by avoiding exposure to antibody-binding moiety removal conditions, which typically involve one or more of reduction, oxidation, hydrolysis, e.g., of ester groups), etc., conditions and may damage target agent moieties, e.g., for protein agent moieties, protein amino acid residues, overall structures, or post- translational changes, e.g., glycans of antibodies) thereof. In some embodiments, provided technologies can provided improved efficiency, e.g., in terms of reaction rates or conversion percentages), increased yield, increased purity/homogeneity, or enhanced selectivity, particularly compared to reference technologies wherein a reaction partner containing no antibody-binding moieties is used, without introducing step(s) for antibody-binding moiety removal, e.g., antibody-binding moiety is removed in the same step as cellular receptor-binding moiety conjugation. [00271] In some embodiments, the invention provides products of provided processes, which have low levels of damage to antibody moieties compared to processes comprising steps performed for antibody-binding moiety removal but not for substantial conjugation of moieties of interest, e.g. target- binding moieties. In some embodiments, provided product agent compositions have high homogeneity, e.g., regarding the number of cellular receptor-binding moiety per antibody moiety, or positions of amino acid residues in antibody moieties conjugated to moieties of interest) compared to reference product compositions, e.g., those from technologies without using antibody-binding moieties, or using extra step(s) for antibody-binding moiety removal, e.g., not using reaction partners described in this specification which comprise a reactive group between an antibody-binding moiety and a cellular receptor-binding moiety. [00272] In some embodiments, the invention provides a product agent which is an agent comprising an antibody moiety, a cellular receptor-binding moiety and optionally a linker moiety linking an antibody-binding moiety and a cellular receptor-binding moiety. In some embodiments, the invention composes such agents.

85 30124-WO-PCT [00273] In some embodiments, the invention provides a composition comprising a plurality of agents, wherein each agent independently comprises: an antibody moiety, a cellular receptor-binding moiety, and optionally a linker moiety linking an antibody-binding moiety and a cellular receptor-binding moiety. [00274] In some embodiments, product agents are MATE agents. In some embodiments, an antibody agent moiety comprises IgG Fc region. In some embodiments, an antibody moiety is connected to a cellular receptor-binding moiety through an amino group optionally through a linker. In some embodiments, it is through a lysine residue wherein the amino group of the side chain is connected to a cellular receptor-binding moiety optionally through a linker, e.g., forming −NH−C(O)− as part of an amide group, a carbamate group, etc. [00275] In some embodiments, selected locations of antibody moieties are used for conjugation. In some embodiments, K246 or K248 of an antibody agent (EU numbering, or corresponding residues) are conjugation locations. In some embodiments, a conjugation location is K246 of heavy chain (unless otherwise specified, locations in this specification include corresponding residues in, e.g., changed sequence, e.g., longer, shorter, rearranged, etc., sequences. In some embodiments, a location is K248 of heavy chain. In some embodiments, a location is K288 or K290 of heavy chain. In some embodiments, a location is K288 of heavy chain. In some embodiments, a location is K290 of heavy chain. In some embodiments, a location is K317. In some embodiments, an antibody moiety is a moiety of an IgG1 antibody or a fragment thereof. In some embodiments, an antibody moiety is a moiety of an IgG2 antibody or a fragment thereof. In some embodiments, an antibody moiety is a moiety of an antibody or a fragment thereof. In some embodiments, a composition comprises a plurality of MATE agents, wherein antibody moieties of the plurality of MATE agents are independently an antibody moiety of an IgG1, IgG2, or IgG4 antibody, or a fragment thereof. [00276] In some embodiments, antibody heavy chains are selectively conjugated/labeled over light chains. [00277] In some embodiments, in provided agents, e.g., agents of formula AGN101 or AGN102, or a salt thereof) substantially all conjugation sites of antibody moieties have the same changes, e.g., all share the same moieties of interest optionally connected through the same linker moieties. In some embodiments, no conjugation sites bear different changes, e.g., different moieties of interest or no moieties of interest or different linker moieties.

86 30124-WO-PCT [00278] In some embodiments, about 10%-100% of all, or substantially all, moieties of interest, e.g., target-binding moieties, conjugated to antibody moieties of a particular type of antibodies, e.g., IgG1, or fragments thereof are conjugated to one or more particularly sites, typically one or two particularly sites, e.g., K246 and K248 of an IgG1 heavy chain and amino acid residues corresponding thereto. In some embodiments, about 10%-100% of all, or substantially all, moieties of interest, e.g., target-binding moieties, conjugated to antibody moieties of IgG2 antibodies or fragments thereof are at K251 and K253 of an IgG2 heavy chain and amino acid residues corresponding thereto. In some embodiments, about 10%-100% of all, or substantially all, moieties of interest, e.g., target-binding moieties, conjugated to antibody moieties of IgG2 antibodies or fragments thereof are at K239 and K241 of a heavy chain and amino acid residues corresponding thereto. In some embodiments, about 10%-100% of all, or substantially all, moieties of interest, e.g., for a plurality of agents, for a composition, etc. are conjugated to antibody moieties of IgG1, IgG2, or IgG4 antibodies, or fragments thereof, e.g., for conjugation products with IgG1 antibodies or fragments thereof (antibody moieties being of IgG1 antibodies or fragments thereof), IgG2 antibodies or fragments thereof (antibody moieties being of IgG2 antibodies or fragments thereof), IgG4 antibodies or fragments thereof (antibody moieties being of IgG4 antibodies or fragments thereof), or for conjugation products with IVIG (when certain provided technologies described in this specification are used, selective conjugation with IgG1, IgG2 and IgG4). In some embodiments, a percentage is about 10% or more. In some embodiments, a percentage is about 20% or more. In some embodiments, a percentage is about 25% or more. In some embodiments, a percentage is about 30% or more. In some embodiments, a percentage is about 40% or more. In some embodiments, a percentage is about 50% or more. In some embodiments, a percentage is about 60% or more. In some embodiments, a percentage is about 65% or more. In some embodiments, a percentage is about 70% or more. In some embodiments, a percentage is about 75% or more. In some embodiments, a percentage is about 80% or more. In some embodiments, a percentage is about 85% or more. In some embodiments, a percentage is about 90% or more. In some embodiments, a percentage is about 95% or more. In some embodiments, a percentage is about 100%. [00279] In some embodiments, a composition comprises a plurality of agents, e.g., MATE agents, agents of formula AGN101 or AGN102, or a salt thereof, each independent comprising a cellular receptor-binding moiety, an antibody moiety, and optionally a linker moiety linking a cellular receptor- binding moiety and an antibody moiety. In some embodiments, substantially all target-binding moieties of a plurality of agents are the same. In some embodiments, substantially all target-binding moieties of a plurality of agents comprise peptide moieties of a common amino acid sequence. In some

87 30124-WO-PCT embodiments, substantially all target-binding moieties of a plurality of agents are peptide moieties of a common amino acid sequence. In some embodiments, substantially all conjugation sites of antibody moieties in a plurality of agents have the same changes, e.g., all share the same moieties of interest optionally connected through the same linker moieties. In some embodiments, no conjugation sites of a plurality of agents bear different changes, e.g., different moieties of interest or no moieties of interest or different linker moieties. In some embodiments, a plurality of agents does not have agents that share the same (or substantially the same) antibody moieties but different changes, e.g., different moieties of interest or no moieties of interest or different linker moieties. In some embodiments, agents that share the same (or substantially the same) antibody moieties but different changes, e.g., different moieties of interest or no moieties of interest or different linker moieties) are intermediates of multiple-step preparations, e.g., comprising steps for removal of antibody-binding moieties in addition to steps for cellular receptor-binding moiety conjugation) of final product agents. [00280] In some embodiments, the invention provides a composition comprising a plurality of agents each of which independently comprising: an antibody moiety, a cellular receptor-binding moiety, and optionally a linker moiety linking the antibody moiety and the cellular receptor-binding moiety; wherein antibody moieties of agents of the plurality comprise a common amino acid sequence, and agents of the plurality share a common cellular receptor-binding moiety independently at least one common amino acid residue of the common amino acid sequence; and wherein about 1%-100% of all agents that comprise an antibody moiety that comprise the common amino acid sequence and the cellular receptor-binding moiety are agents of the plurality. [00281] In some embodiments, the invention provides a composition comprising a plurality of agents each of which independently comprising: an antibody moiety, a cellular receptor-binding moiety, and optionally a linker moiety linking an antibody moiety and a cellular receptor-binding moiety; wherein agents of the plurality share the same or substantially the same antibody moiety, and a cellular receptor-binding moiety at least one common location; and wherein about 1%-100% of all agents that comprise the antibody moiety and the cellular receptor-binding moiety are agents of the plurality.

88 30124-WO-PCT [00282] In some embodiments, an antibody moiety is a moiety of an IgG1 antibody or a fragment thereof. In some embodiments, an antibody moiety is a moiety of an IgG2 antibody or a fragment thereof. In some embodiments, an antibody moiety is a moiety of an IgG3 antibody or a fragment thereof. In some embodiments, an antibody moiety is a moiety of an antibody or a fragment thereof. In some embodiments, about 1-100% of all moieties of interest are at common locations. In some embodiments, a cellular receptor-binding moiety is a cellular receptor-binding moiety as described in this specification. In some embodiments, agents of a plurality are each independently of formula AGN101 or AGN102, or a salt thereof. [00283] In some embodiments, antibody moieties of agents of a plurality comprise a common amino acid sequence. In some embodiments, antibody moieties of agents of a plurality comprise a common amino acid sequence in a Fc region. In some embodiments, antibody moieties of agents of a plurality comprise a common Fc region. In some embodiments, antibody moieties of agents of a plurality can bind a common antigen specifically. In some embodiments, antibody moieties are monoclonal antibody moieties. In some embodiments, antibody moieties are polyclonal antibody moieties. In some embodiments, antibody moieties bind to two or more different antigens. In some embodiments, antibody moieties bind to two or more different proteins. In some embodiments, antibody moieties are IVIG moieties. [00284] In some embodiments, a cellular receptor-binding moiety in an agent of a plurality is a cellular receptor-binding moiety. In some embodiments, each cellular receptor-binding moiety is independently a cellular receptor-binding moiety. In some embodiments, a composition comprises a plurality of agents, antibody moieties of agents of the plurality comprise a common amino acid sequence, and agents of a plurality share a common cellular receptor-binding moiety independently linked to a common amino acid residue in the common amino acid sequence, each independently and optionally through a linker; and wherein about 1%-100% of all agents that comprise an antibody moiety that comprises a common amino acid sequence and a common cellular receptor-binding moiety independently comprise a common cellular receptor-binding moiety linked to a common amino acid residue independently and optionally through a linker. In some embodiments, a composition comprises a plurality of agents, antibody moieties of agents of a plurality comprise a common amino acid sequence, and agents of a plurality share a common cellular receptor-binding moiety independently linked to a common amino acid residue in the common amino acid sequence, each independently through a common linker; and wherein about 1%-100% of all agents that comprise an antibody moiety that comprises a common amino acid sequence and a common cellular receptor-binding moiety

89 30124-WO-PCT independently comprise a common cellular receptor-binding moiety linked to a common amino acid residue independently and through a common linker. In some embodiments, a composition comprises a plurality of agents, antibody moieties of agents of a plurality comprise a common amino acid sequence, and agents of a plurality share a common cellular receptor-binding moiety independently linked to a common amino acid residue in the common amino acid sequence, each independently and optionally through a linker; and wherein about 1%-100% of all agents that comprise an antibody moiety that comprises a common amino acid sequence and a common cellular receptor-binding moiety are agents of a plurality. In some embodiments, a composition comprises a plurality of agents, wherein antibody moieties of agents of a plurality comprise a common amino acid sequence, and agents of a plurality share a common cellular receptor-binding moiety independently linked to a common amino acid residue in the common amino acid sequence, each independently through a common linker; and wherein about 1%-100% of all agents that comprise an antibody moiety that comprises a common amino acid sequence, a common cellular receptor-binding moiety, and a common linker are agents of a plurality. [00285] In some embodiments, “at least one” or “one or more” is 1-1000, 1-500, 1-200, 1-100, 1-90, 1-80, 1-70, 1-60, 1-50, 1-40, 1-30, 1-20, 1-10, 1-5, or about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or more. In some embodiments, it is one. In some embodiments, it is two or more. In some embodiments, it is about 3. In some embodiments, it is about 4. In some embodiments, it is about 5. In some embodiments, it is about 6. In some embodiments, it is about 7. In some embodiments, it is about 8. In some embodiments, it is about 9. In some embodiments, it is about 10. In some embodiments, it is about 10 or more. [00286] In some embodiments, a common amino acid sequence comprises 1-1000, 1-500, 1-400, 1- 300, 1-200, 1-100, 1-50, 10-1000, 10-500, 10-400, 10-300, 10-200, 10-100, 10-50, 20-1000, 20-500, 20- 400, 20-300, 20-200, 20-100, 20-50, 50-1000, 50-500, 50-400, 50-300, 50-200, 50-100, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 200, 250, 300, 400, 500, 600 or more amino acid residues. In some embodiments, a length is at least 5 amino acid residues. In some embodiments, a length is at least 10 amino acid residues. In some embodiments, a length is at least 50 amino acid residues. In some embodiments, a length is at least 100 amino acid residues. In some embodiments, a length is at least 150 amino acid residues. In some embodiments, a length is at least 200 amino acid residues. In some embodiments, a length is at least 300 amino acid residues. In some embodiments, a length is at least 400 amino acid residues. In some embodiments, a length is at least 500 amino acid residues. In some embodiments, a length is at least 600 amino acid residues.

90 30124-WO-PCT [00287] In some embodiments, a common amino acid sequence is at least 10%-100%, 50%-100%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% of an amino acid sequence of an antibody moiety, a protein agent moiety, etc. In embodiments, it is 10% or more. In some embodiments, it is 20% or more. In some embodiments, it is 30% or more. In some embodiments, it is 40% or more. In some embodiments, it is 50% or more. In some embodiments, it is 60% or more. In some embodiments, it is 70% or more. In some embodiments, it is 80% or more. In some embodiments, it is 90% or more. In some embodiments, it is 100%. [00288] In some embodiments, in a common amino acid sequence, one and only one amino acid residue is linked to a common cellular receptor-binding moiety, e.g., a common cellular receptor-binding moiety. In some embodiments, in a common amino acid sequence, two and only two amino acid residues are linked to a common cellular receptor-binding moiety, e.g., a common cellular receptor- binding moiety. In some embodiments, in a common amino acid sequence, two or more amino acid residues are linked to a common cellular receptor-binding moiety, e.g., a common cellular receptor- binding moiety. In some embodiments, each common cellular receptor-binding moiety, e.g., a common cellular receptor-binding moiety, is independently linked to an amino acid residue in a common amino acid sequence. [00289] In some embodiments, a common amino acid sequence comprises one or more amino acid residues selected from K246 and K248 of an IgG1 heavy chain and amino acid residues corresponding thereto, K251 and K253 of an IgG2 heavy chain and amino acid residues corresponding thereto, and K239 and K241 of an antibody heavy chain and amino acid residues corresponding thereto. In some embodiments, a common amino acid sequence comprises one or more amino acid residues selected from K246 and K248 of an IgG1 heavy chain and amino acid residues corresponding thereto. In some embodiments, a common amino acid sequence comprises one or more amino acid residues selected from K251 and K253 of an IgG2 heavy chain and amino acid residues corresponding thereto. In some embodiments, a common amino acid sequence comprises one or more amino acid residues selected from K239 and K241 of an antibody heavy chain and amino acid residues corresponding thereto. In some embodiments, a cellular receptor-binding moiety is connected to this amino acid residue (unless explicitly noted, optionally through a linker moiety). In some embodiments, each cellular receptor- binding moiety is connected to this amino acid residue each optionally and independently through a linker moiety. [00290] In some embodiments, antibody moieties share a high percentage of amino acid sequence homology. In some embodiments, the amino acid sequence homology is about 50%-100%. In some

91 30124-WO-PCT embodiments, the amino acid sequence homology is a percentage selected from the Markush group of percentages consisting of 50%, 60%, 70%, 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, at least 60%, at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, and at least 99%. [00291] In some embodiments, a percentage used in this specification is a percentage selected from the Markush group of percentages consisting of about 1%-100%, about 10% or more, about 20% or more, about 25% or more, about 30% or more, about 40% or more, about 50% or more, about 60% or more, about 65% or more, about 70% or more, about 75% or more, about 80% or more, about 85% or more, about 90% or more, about 95% or more, about 100%. [00292] In some embodiments, antibody moiety of agents of a plurality comprises a common Fc region or a fragment thereof. [00293] In some embodiments, moieties of interest of agents of a plurality are at specific locations. In some embodiments, all moieties of interest are at amino acid residues of a common amino acid sequence. In some embodiments, all moieties of interest are at common locations of amino acid residues of a common amino acid sequence. In some embodiments, the number of common locations is 1. In some embodiments, it is 2. In some embodiments, it is 3. In some embodiments, it is 4. In some embodiments, antibody moieties comprise two heavy chains or fragments thereof, and the number of common locations is 2 (one on each chain). In some embodiments, common locations are selected from K246 and K248 of an IgG1 heavy chain and amino acid residues corresponding thereto, K251 and K253 of an IgG2 heavy chain and amino acid residues corresponding thereto, and K239 and K241 of an antibody heavy chain and amino acid residues corresponding thereto. [00294] In some embodiments, agents of a plurality share a common cellular receptor-binding moiety independently at least one location. In some embodiments, agents of a plurality share a common cellular receptor-binding moiety and linker independently at least one location. In some embodiments, moieties of interest at two or more or all locations comprise a common cellular receptor-binding moiety. In some embodiments, moieties of interest are the same. [00295] In some embodiments, agents share common changes at least one common amino acid residue. In some embodiments, agents of a plurality share common changes at each location connected to a cellular receptor-binding moiety and optionally a linker. In some embodiments, agents of a plurality the same −L^PM−TBT at each location connected to a linker moiety. [00296] In some embodiments, a location is selected from K246, K248, K288, K290, K317 of antibody agents and locations corresponding thereto. In some embodiments, a location is selected from K246 and

92 30124-WO-PCT K248, and locations corresponding thereto. In some embodiments, a location is selected from K288 and K290, and locations corresponding thereto. In some embodiments, a location is K246 or a location corresponding thereto. In some embodiments, a location is K248 or a location corresponding thereto. In some embodiments, a location is K288 or a location corresponding thereto. In some embodiments, a location is K290 or a location corresponding thereto. In some embodiments, a location is K317 or a location corresponding thereto. In some embodiments, a location is K185 of light chain or a location corresponding thereto. In some embodiments, a location is K187 of light chain or a location corresponding thereto. In some embodiments, a location is K133 of heavy chain or a location corresponding thereto. In some embodiments, a location is K246 or K248 of heavy chain or a location corresponding thereto. In some embodiments, a location is K414 of heavy chain or a location corresponding thereto. In some embodiments, a common sequence is a sequence that is about or at least about 10-100, 20-50, e.g., at least about 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100, amino acid residues in length, and comprises one or more of such residues or residues corresponding thereto. In some embodiments, a common sequence is a sequence that is about or at least about 10-100, 20-50, e.g., about or at least about 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100, amino acid residues in length, and comprises one, two or more residues selected from K246 and K248 of an IgG1 heavy chain and amino acid residues corresponding thereto, K251 and K253 of an IgG2 heavy chain and amino acid residues corresponding thereto, and K239 and K241 of an antibody heavy chain and amino acid residues corresponding thereto. [00297] In some embodiments, about 1%-100% of all agents that comprise an antibody moiety and a cellular receptor-binding moiety are agents of a plurality. In some embodiments, about 1%-100% of all agents that comprise an antibody moiety that comprises a common amino acid sequence and a cellular receptor-binding moiety are agents of a plurality. In some embodiments, about 1%-100% of all agents that comprise an antibody moiety that comprise a common amino acid sequence or can bind to a common antigen and a cellular receptor-binding moiety are agents of a plurality. In some embodiments, about 1%-100% of all agents that comprise an antibody moiety are agents of a plurality. In some embodiments, about 1%-100% of all agents that comprise an antibody moiety that comprise the common amino acid sequence are agents of a plurality. In some embodiments, about 1%-100% of all agents that comprise a protein agent moiety that comprise the common amino acid sequence are agents of a plurality. In some embodiments, a range of all agent agents that comprise an antibody agent moiety that comprise the common amino acid sequence or can bind to the common antigen are selected from a Markush group of ranges where the agents are of a plurality consisting of about 1%-

93 30124-WO-PCT 100%, about 5%-100%, 10%-100%, about 20%-100%, about 25%-100%, about 30%-100%, and about 40%-100%, about 50%-100%. In some embodiments, a range of all agent agents that comprise an antibody agent moiety that comprise the common amino acid sequence or can bind to the common antigen are selected from a Markush group of ranges where the agents are of a plurality consisting of about 5%, about 10%, about 20%, about 25%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99%, and about 100%. In some embodiments, a range of all agent agents that comprise an antibody agent moiety that comprise the common amino acid sequence or can bind to the common antigen are selected from a Markush group of ranges where the agents are of a plurality consisting of at least about 5%, at least about 10%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50 at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, and at least about 99%. [00298] In some embodiments, each agent of the plurality does not have −S−Cy−, wherein −Cy− is optionally substituted 5-membered monocyclic ring, does not have −S−S− which is not formed by cysteine residues and does not have −SH or salt form thereof that is not of a cysteine residue. In some ^{embodiments, each agent of the plurality does not have −S−CH} _{2−CH2−. In some embodiments, each} agent of the plurality does not have a moiety that can specifically bind to an antibody agent. In some embodiments, a composition is substantially free from a moiety that can specifically bind to an antibody agent. [00299] In some embodiments, the invention provides product agent compositions comprising product agents, e.g., agents of formula AGN101 or AGN102, or a salt thereof. In some embodiments, a product agent composition, e.g., aa agent composition formed from certain methods, comprises a product agent comprising an antibody moiety and a cellular receptor-binding moiety and optionally a linker, e.g., an agent of formula AGN101 or AGN102, or a salt thereof, a released antibody-binding moiety, e.g., a compound comprising R^LG−(L^LG1)_0-1−(L^LG2)_0-1−(L^LG3)_0-1−(L^LG4)_0-1−) or a compound comprising a released antibody-binding moiety, e.g., a compound having the structure of R^LG−(L^LG1)_0-1−(L^LG2)_0-1−(L^LG3)_0- ₁−(L^LG4)_0-1−H or a salt thereof, and a reaction partner, e.g., a composition of matter of formula AGN301 or a salt thereof. In some embodiments, released antibody-binding moieties may bind to antibody moieties in target agents or formed product agents. Several technologies are available to separate released antibody-binding moieties from antibody moieties under this specification, for example, in

94 30124-WO-PCT some embodiments, contacting a composition with a composition comprising glycine at certain pH. In some embodiments, each agent of a plurality is independently this product agent. Reactive Group [00300] In some embodiments, provided agents, compounds, e.g., those useful as reaction partners such as first agents, comprise reactive groups, e.g., RG. In some embodiments, reactive groups, e.g., RG) are between antibody-binding moieties, e.g., ABT) and moieties of interest, e.g., MOI), and are optionally and independently linked to antibody-binding moieties and moieties of interest via linkers. In some embodiments, RG is a reaction group as described in this specification. [00301] In some embodiments, reactive groups when used in agents that comprise no antibody- binding moieties react slowly and provide low level of, in some embodiments, substantially no conjugation of moieties of interest with target agents. As shown in this specification, combination of reactive groups with antibody-binding moieties in the same agents, e.g., as in compounds of formula AGN301 or salts thereof, can promote reactions between reactive groups and target agents, enhance reaction efficiency, reduce side reactions, or improve reaction selectivity, e.g., in terms of target sites wherein conjugation of moieties of interest with target agents occurs. [00302] Reactive groups in agents can react with several types of groups in target agents. In some embodiments, reactive groups in agents selectively react with amino groups of target agents, e.g., −NH₂ groups on side chains of lysine residues of proteins. In some embodiments, reactive groups when used in agents, e.g., those of formula AGN301 or salts thereof, selectively react with particular sites of target agents, e.g., as shown in examples in this specification, one or more of K246, K248, K288, K290, K317, etc. of IgG1, K251, K253, etc. for IgG2, K239, K241 for IgG4 , etc. In embodiments, a site is K246 or K248 of an antibody heavy chain. In some embodiments, sites are K246 or K248 of an antibody heavy chain. In some embodiments, a site is K246 of an antibody heavy chain. In some embodiments, a site is K248 of an antibody heavy chain. In some embodiments, a site is K288 or K290 of an antibody heavy chain. In some embodiments, a site is K288 of an antibody heavy chain. In some embodiments, a site is K290 of an antibody heavy chain. In some embodiments, a site is K317. In some embodiments, a site is K414 of an antibody heavy chain. In some embodiments, a site is K185 of an antibody light chain. In some embodiments, a site is K187 of an antibody light chain. In some embodiments, sites are K251 or K253 of an IgG2 heavy chain. In some embodiments, a site is K251 of an IgG2 heavy chain. In some embodiments, a site is K253 of an IgG2 heavy chain. In some embodiments, sites are K239 or K241 of an antibody heavy chain. In some embodiments, a site is K239 of an antibody heavy chain. In some embodiments, a site is K241 of an antibody heavy chain. In some embodiments, conjugation selectively

95 30124-WO-PCT occurs at one or more heavy chain sites over light chain sites. In some embodiments, for technologies without antibody-binding moieties, conjugation occurs at light chain sites more than heavy chain sites. [00303] In some embodiments, a reactive group, e.g., RG, is or comprises an ester group. In some embodiments, a reactive group, e.g., RG, is or comprises an electrophilic group, e.g., a Michael acceptor. [00304] In some embodiments, a reactive group, e.g., RG, is or comprises −L^RG1−L^RG2−, wherein each of L^RG1 and L^RG2 is independently L. In embodiments, a reactive group, e.g., RG, is or comprises −L^LG4−L^RG1−L^RG2−, wherein each variable is as described in this specification. In some embodiments, a reactive group, e.g., RG, is or comprises −L^LG3−L^LG4−L^RG1−L^RG2−, wherein each variable is as described in this specification. In some embodiments, a reactive group, e.g., RG, is or comprises −L^LG2−L^LG3−L^LG4−L^RG1−L^RG2−, wherein each variable is as described in this specification. In some embodiments, a reactive group, e.g., RG, is or comprises −L^LG4−L^RG2−, wherein each variable is as described in this specification. In some embodiments, a reactive group, e.g., RG, is or comprises −L^LG3−L^LG4−L^RG2−, wherein each variable is as described in this specification. In some embodiments, a reactive group, e.g., RG, is or comprises −L^LG2−L^LG3−L^LG4−L^RG2−, wherein each variable is as described in this specification. [00305] In some embodiments, L^LG4 is −O−. In some embodiments, L^LG4 is −N(R)−. In some embodiments, L^LG4 is −NH−. [00306] In some embodiments, L^LG3 is or comprises an optionally substituted aryl ring. In some embodiments, L^LG3 is or comprises a phenyl ring. In some embodiments, an aryl or phenyl ring is substituted. In some embodiments, a substituent is an electron-withdrawing group as described in this specification, e.g., −NO₂, −F, etc. [00307] In some embodiments, L^RG1 is a covalent bond. In some embodiments, L^RG1 is not a covalent bond. In some embodiments, L^RG1 is −S(O)₂−. [00308] In some embodiments, L^RG2 is −C(O)−. In some embodiments, a reactive group is or comprises −L^LG4−C(O)−, wherein each variable is as described in this specification. In some embodiments, a reactive group is or comprises −L^LG3−L^LG4−C(O)−, wherein each variable is as described in this specification. In some embodiments, a reactive group is or comprises −L^LG2−L^LG3−L^LG4−C(O)−, wherein each variable is as described in this specification. [00309] In some embodiments, L^RG2 is −L^RG3−C(=CR^RG1R^RG2)−CR^RG3R^RG4−, wherein each of R^RG1, R^RG2, R^RG3 and R^RG4 is independently −L−R’, and L^RG3 is −C(O)−, −C(O)O−, −C(O)N(R’)−, −S(O)−, −S(O)₂−, −P(O)(OR’)−, −P(O)(SR’)−, or −P(O)(N(R’)2)−. In some embodiments, each of R^RG1, R^RG2, R^RG3 and R^RG4 is independently R’. In some embodiments, one or more of R^RG1, R^RG2, R^RG3 and R^RG4 is independently −H. In

96 30124-WO-PCT embodiments, L^RG3 is −C(O)−. In some embodiments, L^RG3 is −C(O)O−. In some embodiments, −O−, −N(R’)−, etc. of L^RG3 is bonded to L^PM. [00310] In some embodiments, R^RG1 is −H. In embodiments, R^RG3 is −H. [00311] In some embodiments, L^RG2 is optionally substituted −L^RG3−C(=CHR^RG2)−CHR^RG4−, wherein each variable is as described in this specification. [00312] In some embodiments, R^RG2 and R^RG4 are taken with their intervening atoms to form an optionally substituted ring as described in this specification. In some embodiments, a formed ring is an optionally substituted 3-10-membered monocyclic or bicyclic ring having 0-5 heteroatoms. In some embodiments, a formed ring is an optionally substituted 3-10-membered cycloaliphatic ring. In some embodiments, a formed ring is selected from the Markush group consisting of optionally substituted cycloaliphatic rings consisting of a 3-8-membered cycloaliphatic ring, a 5-8-membered cycloaliphatic ring., a 5-membered cycloaliphatic ring, a 6-membered cycloaliphatic ring, and a 7-membered cycloaliphatic ring. In some embodiments, a formed ring is substituted. In some embodiments, a formed ring is not substituted. In some embodiments, a formed ring has no additional unsaturation in addition to the double bond in C(=CHR^RG2) or C(=CR^RG1R^RG2). [00313] In some embodiments, −C(=CHR^RG2)−CHR^RG4 or −C(=CR^RG1R^RG2)−CR^RG3R^RG4 is optionally . In some embodiments, −[C(=CHR^RG2)−CHR^RG4]−L^RG3− or −[C(=CR^RG1R^RG2)−CR^RG3R^RG4]−L^RG3− is optionally embodiments, −L^RG1−[C(=CHR^RG2)−CHR^RG4]−L^RG3− or substituted some embodiments, −L^RG1−[C(=CHR^RG2)−CHR^RG4]−L^RG3− or −L^RG1−[C −L^RG3− is optionally substituted. [00314] In some embodiments, the reactive group has a structure disclosed in TABLE 3 of the published International patent application WO 2024/228935 (Biohaven Therapeutics Ltd.). [00315] In some embodiments, −L^LG4−L^RG2− is −O−C(O)− or −S−C(O)−. In some embodiments, −L^LG4−L^RG1−L^RG2− is −S−C(O)−.

97 30124-WO-PCT [00316] In some embodiments, −L^LG4−L^RG2− is −N(−)−C(O)−, wherein N is a ring atom of an optionally substituted heteroaryl ring. In some embodiments, −L^LG4−L^RG2− is −N(−)−C(O)−, wherein N is a ring atom of L^LG4 which is or comprises an optionally substituted heteroaryl ring. In some embodiments, −L^LG4−L^RG2− is −N(−)−C(O)−O−, wherein N is a ring atom of L^LG4 which is or comprises an optionally substituted heteroaryl ring. [00317] In some embodiments, L^RG2 is optionally substituted −CH₂−C(O)−, wherein −CH₂− is bonded to an electron-withdrawing group comprising or connected to an antibody-binding moiety. In some embodiments, L^RG2 is optionally substituted −CH₂− bonded to an electron-withdrawing group comprising or connected to an antibody-binding moiety. In some embodiments, L^RG1 is an electron-withdrawing group. In some embodiments, L^RG1 is selected from the Markush group consisting of −C(O)−, −S(O)−, −S(O)₂−, −P(O(OR)−, −P(O(SR)−, −P(O(N(R)₂)−, −OP(O(OR)−, −OP(O(SR)−, and −OP(O(N(R)₂)−. [00318] In some embodiments, L^RG2 is optionally substituted −CH₂−C(O)−, wherein −CH₂− is bonded to a leaving group comprising or connected to an antibody-binding moiety. In some embodiments, L^RG2 is optionally substituted −CH₂− bonded to a leaving group comprising or connected to an antibody-binding moiety. In some embodiments, L^RG1 is selected from the Markush group consisting of −O−C(O)−, −OS(O)₂−, −OP(O(OR)−, −OP(O(SR)−, and −OP(O(N(R)₂)−. [00319] In some embodiments, a reactive group reacts with an amino group of a target agent. In some embodiments, an amino group is −NH₂ of the side chain of a lysine residue. [00320] In some embodiments, a target agent is a protein agent. In some embodiments, a target agent is an antibody agent. In some embodiments, a reactive group reacts with an amino acid residue of this protein or antibody agent. In some embodiments, an amino acid residue is a lysine residue. In some embodiments, a reactive group reacts with −NH₂ of the side chain of a lysine residue. In some embodiments, a reactive group is or comprises −C(O)−O−, it reacts with −NH₂, e.g., of the side chain of a lysine residue), and forms an amide group −C(O)−O− with the −NH₂. [00321] In some embodiments, reactive groups, e.g., a first reactive group, a second reactive group, etc., are at terminal locations. In some embodiments, agents such as first agents comprise first reactive groups linked to target-binding moieties optionally through linker moieties, and do not have antibody- binding moieties.

98 30124-WO-PCT [00322] In some embodiments, the invention provides methods for preparing a composition comprising a plurality of agents, wherein each agent independently comprises: an antibody moiety, a cellular receptor-binding moiety, and optionally a linker moiety linking an antibody moiety and a cellular receptor-binding moiety; which method comprise: contacting a plurality of agents each of which independently comprises a reactive group with a plurality of antibody agents. [00323] In some embodiments, an agent comprising a reactive group comprises an antibody-binding moiety, a cellular receptor-binding moiety and optionally a linker. In some embodiments, agents comprising a reactive group share the same cellular receptor-binding moiety. In some embodiments, agents comprising a reactive group share the same structure. In some embodiments, antibody molecules are of such structures, properties or activities to provide antibody moieties in agents described in this specification. In some embodiments, a plurality of antibody molecules comprises two or more IgG subclasses. In some embodiments, a plurality of antibody molecules comprises IgG1. In some embodiments, a plurality of antibody molecules comprises IgG2. In some embodiments, a plurality of antibody molecules comprises IgG4. In some embodiments, a plurality of antibody molecules comprises IgG1 and IgG2. In some embodiments, a plurality of antibody molecules comprises IgG1, IgG2 and IgG4. In some embodiments, a plurality of antibody molecules comprises IgG1, IgG2, IgG3 and IgG4. In some embodiments, a plurality of antibody molecules is IVIG antibody molecules. [00324] In some embodiments, provided agents comprise a reactive group, . In some embodiments, −C(O)− is connected to a cellular receptor-binding moiety, −(Xaa)y−, optionally through a linker and the other end is connected to an antibody-binding moiety. In some reacts with an amino group of another moiety, e.g., an antibody moiety, forming an the moiety and releasing a moiety which is or comprises antibody- binding moiety. In some embodiments, an amino group is −NH₂ of a lysine side chain. In some embodiments, −C(O)− is connected to a cellular receptor-binding moiety, or a moiety comprising −(Xaa)y−, optionally through a linker and the other end is connected to R’ or an optional substituent. In

99 30124-WO-PCT some embodiments, provided agents comprise optionally . Such reactive groups may be useful for conjugation with detection, diagnosis, or Persons having ordinary skill in the biomedical art know that many agents, and many e.g., click chemistry, reactions based on functional groups such as amino groups, e.g., amide formation), hydroxyl groups, carboxyl groups, etc. can be used for conjugation under this specification. [00325] In some embodiments, antibody-binding moieties bind to Fc regions of antibodies. In some embodiments, reactions occur at residues at Fc regions. In some embodiments, target-binding moieties are conjugated to residues of Fc regions, optionally through linker moieties. In some embodiments, a residue is a Lys residue. In some embodiments, an antibody is or comprises IgG1. In some embodiments, an antibody is or comprises IgG2. In some embodiments, an antibody is or comprises IgG4. In some embodiments, an antibody composition used in a method comprises IgG1 and IgG2. In some embodiments, an antibody composition used in a method comprises IgG1, IgG2 and IgG4. In some embodiments, an antibody composition used in a method comprises IgG1, IgG2, IgG3 and IgG4. [00326] In some embodiments, a product is or comprises IgG1. In some embodiments, a product is or comprises IgG2. In some embodiments, a product is or comprises IgG4. In some embodiments, a product composition comprises IgG1 and IgG2. In some embodiments, a product composition comprises IgG1, IgG2 and IgG4. In some embodiments, a product composition comprises IgG1, IgG2, IgG3 and IgG4. [00327] In some embodiments, provided agents comprising antibody moieties provide one or more or substantially all antibody immune activities, e.g. for recruiting one or more types of immune cells or provide short-term and long-term immune activities. In some embodiments, provided agents comprising antibody moieties do not significantly reduce one or more or substantially all relevant antibody immune activities. In some embodiments, provided agents comprising antibody moieties improve one or more or substantially all relevant antibody immune activities, e.g., compared to antibody moieties by themselves. In some embodiments, provided agents provides comparable or better stability compared to antibody moieties by themselves, e.g., home time in blood. In some embodiments, antibody moieties in provided agents can bind to FcRy of immune cells, e.g., several FcRy of immune effector cells for desired immune activities, typically, at comparable or better levels. In some embodiments, antibody moieties in provided agents have comparable Fab/antigen-binding capabilities. In some embodiments, antibody moieties in provided agents have comparable Fab/antigen-binding capabilities. In some embodiments, antibody moieties in provided agents provide FcRn-binding. In some embodiments,

100 30124-WO-PCT antibody moieties in provided agents provide FcRn-binding, e.g., for antibody recycle or prolonged half- life. In some embodiments, provided technologies are useful for changing blood-derived IgG products as provided technologies are suitable for and can use all IgG subclasses. [00328] In some embodiments, a provided method comprises one step described below. In some reacts with an amino group of a lysine side chain to form an amide bond with an and releases or a salt form thereof. Pharmaceutically acceptable excipients. [00329] Formulations suitable for parenteral administration, such as by intraarticular (in the joints), intravenous, intramuscular, intratumoral, intradermal, intraperitoneal, and subcutaneous routes, include aqueous and non-aqueous, isotonic sterile injection solutions, which can have antioxidants, buffers, bacteriostats, and solutes that render the formulation isotonic with the blood of the intended recipient, and aqueous and non-aqueous sterile suspensions that can include suspending agents, solubilizers, thickening agents, stabilizers, and preservatives. In the practice of this invention, compositions can be administered by intravenous infusion, orally, topically, intraperitoneally, intravesically, or intrathecally. Parenteral administration, oral administration, and intravenous administration are the preferred methods of administration. The formulations of compounds can be presented in unit-dose or multi-dose sealed containers, such as ampules and vials. [00330] Solutions or suspensions used for parenteral, intradermal, or subcutaneous application can include these components: a sterile diluent such as water for injection, saline solution, fixed oils, polyethylene glycols, glycerin, propylene glycol or other synthetic solvents; antibacterial agents such as benzyl alcohol or methyl parabens; antioxidants such as ascorbic acid or sodium bisulfite; chelating agents such as ethylenediaminetetraacetic acid; buffers such as acetates, citrates or phosphates, and agents for the change in tonicity such as sodium chloride or dextrose. The pH can be adjusted with acids or bases, such as hydrochloric acid or sodium hydroxide. The parenteral preparation can be enclosed in ampoules, disposable syringes or multiple dose vials made of glass or plastic. Methods of assessing the chemical structure and function of the agent. [00331] HDX-MS measures the exposure of hydrogen molecules on the surface of a protein or protein complex. The first step causes exposed hydrogen molecules to be readily exchanged with

101 30124-WO-PCT deuterium. Hydrogen molecules buried within the structure, for example at the binding site of an antibody-antigen complex, are not exchanged as readily. [00332] Comparing the deuterium uptake between the free and the complex states of proteins via mass spectrometry provides valuable information about the binding regions. [00333] Protein sequencing. In one method of protein sequencing, eight digestions are prepared using five enzymes (Pepsin, Lys C, Trypsin, Chymotrypsin, Asp N). The digestions for the sample are processed with disulfide reduction, cysteine blocking, and then enzyme digestion. Digestions were analyzed by LC-MS/MS using a Thermo-Fisher Orbitrap fusion™ mass spectrometer. Peptides are characterized from LC -MS/MS data using de nova peptide sequencing and then assembled into antibody sequences. [00334] Competition ELISA assay protocol. [00335] (1) Dilute patient plasma samples at 1:100 in the provided ELISA sample buffer. [00336] (2) Make the working stock solution for the degraders for a final concentration of 400 nM in 115 µl total reaction volume per well. [00337] (3) Incubate 100 ul patient plasma sample with 15 ul of degrader for 2 hours at room temperature. [00338] (4) Transfer 100 ul from this reaction to the EuroImmun anti-PLA2R ELISA plate. [00339] (5) Also transfer the calibrators, and positive and negative controls to the plate. [00340] (6) Incubate for 30 minutes at room temperature. [00341] (7) Empty the wells and wash thrice with 300 ul/well of wash buffer. [00342] (8) Pipette 100 ul of enzyme conjugate into each well of the ELISA plate. [00343] (9) Incubate for 30 minutes at room temperature. [00344] (10) Empty the wells and wash thrice with 300 ul/well of wash buffer. [00345] (11) Pipette 100 ul of substrate solution into each well of the ELISA plate. [00346] (12) Incubate for 15 minutes at room temperature. [00347] (13) Pipette 100 ul of stop solution into each well of the ELISA plate. [00348] (14) Measure absorbance at 450 nm within 30 minutes of adding the stop solution. [00349] ASGPR-mediated endocytosis of anti-PLA2R antibody. [00350] For routine culture of HEK-ASGPR cells, use DMEM high glucose with phenol + 10% FBS + 2 mM glutamine + 1% Pen Strep + 200 ug/ml geneticin. [00351] For seeding of HEK-ASGPR cells in step 2, use DMEM high glucose without phenol + 10% FBS + 2 mM glutamine + 1% Pen Strep + 200 ug/ml geneticin.

102 30124-WO-PCT [00352] (1) Harvest HEK-ASGPR1 cells using Accutase [00353] (2) Seed 30,000 cells/well in 100 ul media/well in poly-D-lysine-coated black TC-treated 96- well plates [00354] (3) The next day, label rabbit anti-PLA2R with anti-rabbit-F(ab)2-AF488 as follows (amounts for 4:1 molar ratio of anti-PLA2R:anti-rabbit-F(ab)2-AF488, with anti-PLA2R at 12.5 nM, for one 96-well plate): [00355] (a) Add 11.6 ul 6B3-1 anti-PLA2R (@1.63 ug/ul) and 2.3 ul anti-rabbit-F(ab)2-Alexa Fluor488 (@ 1.5 ug/ul) to 10.4 ml Opti-MEM. [00356] (b) Invert a couple of times to mix. [00357] (c) Incubate for 30 min at 37 C in the dark, inverting to mix every 10-15 min. [00358] (4) Prepare a 11-point titration series for the degraders using PBS, starting at 20 uM top concentration with three-fold serial dilutions [00359] (5) Remove media from the plate by flicking and dispense 90 ul/well of the anti-PLA2R + anti-rabbit-F(ab)2-AlexaFluor488 mix at the slowest dispense speed [00360] (6) Add 10 ul/well of the degrader titration series to achieve a final top concentration of 2 uM [00361] (7) Place plates in the IncuCyte and scan at 0, 3, 6, 9, 12, 15, 18, 21 and 24 hours [00362] (8) Analyze the images to obtain green fluorescent area per image using the following algorithm parameters: Surface fit segmentation, 0.75 threshold, edge split off, 0.5 µm² hole fill. TABLE 7 Reagents Vendor Cat # DMEM high glucose with phenol Gibco 11960044 DMEM high glucose without phenol Gibco 31053028 Opti-MEM Reduced serum medium Thermo Fisher (Gibco) 31985062 Geneticin 50mg/ml Gibco 10131-035 FBS heat inactivated R&D systems (Optima) S12450H Glutamine Corning 25-005-CI Penicillin Streptomycin Corning 30-002-CI Accutase Stemcell technologies 07920 96-well black, flat clear bottom, poly-D Corning 3842 lysine coated Anti-PLA2R antibody GenScript

103 30124-WO-PCT TABLE 7 Reagents Vendor Cat # Alexa Fluor® 488 AffiniPure™ Goat Anti- Jackson 111-545-006 Rabbit IgG, F(ab')₂ fragment specific ImmunoResearch Immunoglobulin Sequence Analysis [00363] Sequence Analysis Tools. The following free online tools for sequence analysis of immunoglobulin variable regions: (1) NCBI Nucleotide BLAST, (2) IMGT/V Quest program, and (3) NCBI IgBLAST. [00364] Sequence Analysis Materials. B cells prepared by GenScript; RNA-easy Isolation Reagent (Vazyme, Cat. No. : R701-01-AA); PrimeScript™ 1st Strand cDNA Synthesis Kit (Takara, Cat. No.: 6110A). [00365] Sequence Analysis Methods. Total RNA was isolated from the B cells following the technical manual of RNA-easy Isolation Reagent. Total RNA was then reverse-transcribed into cDNA using either isotype-specific anti-sense primers or universal primers following the technical manual of PrimeScript™ 1st Strand cDNA Synthesis Kit. Antibody fragments of heavy chain and light chain were amplified using specific primers according to the standard operating procedure (SOP) of GenScript. Amplified antibody fragments were cloned into a standard cloning vector separately. Colony PCR was performed to screen for clones with inserts of correct sizes. The consensus sequence was provided. [00366] Phospholipase A2 receptor (PLA2R) antibody, IgG with reflex to titer. This commercially- available assay aids in the differential diagnosis of membranous glomerulonephritis (MGN) or nephrotic syndrome of unknown etiology. This assay is commercially-available from ARUP Laboratories. Component Test Code* 2011829. Component Chart Name, Phospholipase A2 Receptor, IgG. LOINC. 82991-1. This assay is New York State approved. [00367] Patient Preparation. Instructions patient must follow before/during specimen collection. [00368] Collect. Specimen type to collect. May include collection media, tubes, kits, etc. [00369] Serum Separator Tube. Specimen preparation, instructions for specimen prep before/after collection and prior to transport. Separate serum from cells ASAP or within two hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (minimum 0.2 mL). [00370] Processes used to perform the test. Semi-Quantitative Cell-Based Indirect Fluorescent Antibody. [00371] Additional information related to the test. If phospholipase A2 receptor antibody, IgG is positive, then a phospholipase receptor A2 antibody, IgG titer can be added.

104 30124-WO-PCT Statistical analyses. [00372] Normal distribution quantitative variables can be expressed as means and standard deviations and compared by an independent-samples t test. For non-normally distributed variables, we used median and interquartile range and analyzed with the Mann-Whitney U test. Categorical data is summarized by percentages. A two-sided p value <0.05 is statistically significant. All statistical tests are performed using SPSS version 16.0. EXAMPLES [00373] The invention is further illustrated by non-limiting EXAMPLES. EXAMPLE 1 Bifunctional degrader directed to anti-PLA2R Abs in idiopathic membranous nephropathy. [00374] Anti-PLA2R degraders were constructed using the reported 31-mer peptide ligand as the antibody-binding moiety. Depleting anti-PLA2R antibodies with a degrader should result in remission of idiopathic membranous nephropathy faster and safer than immunosuppressive therapy. Depleting anti- PLA2R antibodies could treat patients unresponsive to immunosuppressants. Material generation. [00375] The inventors constructed PLA2R bifunctional degraders. TABLE 8 Moiety aPLA2R-binding ASGPR-binding K_D (nM) as assayed by surface moiety moiety plasmon resonance ABT305 31-mer N/A 7 AGN306 31-mer βGN3 23 ± 1 ABT301 31-mer (bicyclic) N/A 0.3 ± 2 AGN302 31-mer (bicyclic) βGN3 10 ± 3 AGN304 31-mer (bicyclic) CF₃ pyrazine 3 ± 0.3 AGN303 31-mer (bicyclic) ⍺GN3 7 ± 1 AGN308 31-mer CF₃ pyrazine 9 ± 2

105 30124-WO-PCT Measure uptake in vitro. [00376] The inventors have successfully measured the uptake of anti-PLA2R antibodies and biodegraders in HepG2 assays. The inventors now have an assay to measure antibody degradation in vitro. The inventors assaying and analyzing patient plasma in this assay. [00377] The inventors are demonstrating the biophysical characterization of peptide alone and degrader to monoclonal anti-PLA2R antibody and patient anti-PLA2R antibody. The inventors are proceeding to measure competition of idiopathic membranous nephropathy anti-PLA2R to PLA2R by Meso Scale Discovery. In vitro toxicity assays. [00378] The inventors successfully completed a hemagglutination assay using bifunctional degraders. TABLE 9 PLA2R degrader hemagglutinin activity assay Agent PLA2R-binding moiety ASGPR 50 500 ligand µM µM AGN306 WQDKGIFVIQSESLKK(CIQAGKSVLTLENKC)K (31-mer) βGN + - AGN307 WQDKGIFVIQSESLKK(CIQAGKSVLTLENKC)K (31-mer) ⍺GN3 + - AGN308 WQDKGIFVIQSESLKK(CIQAGKSVLTLENKC)K (31-mer) CF3 - + pyrazine ABT305 WQDKGIFVIQSESLKK(CIQAGKSVLTLENKC)K (31-mer) None - + AGN302 [WQDKGIFVIQSESLKK(CIQAGKSVLTLENKC)K](bic 31-mer) βGN - - AGN303 [WQDKGIFVIQSESLKK(CIQAGKSVLTLENKC)K](bic 31-mer) ⍺GN3 - - AGN304 [WQDKGIFVIQSESLKK(CIQAGKSVLTLENKC)K](bic 31-mer) CF3 - + pyrazine ABT301 [WQDKGIFVIQSESLKK(CIQAGKSVLTLENKC)K](bic 31-mer) None - - ABT309 VIQSESLKK(CIQAGKSVLTLENKC)K None - - [00379] Both N-C cyclization and shortened peptide (ABT309) show no hemagglutinin activity at 50/500 µM. [00380] AGN306 (βGN3) shows hemagglutinin activity in mice, rats, and humans. AGN302 (βGN3) only shows moderate hemagglutinin activity in rats.

106 30124-WO-PCT TABLE 10 AGN303 and peptide alone show HA activity at 5 mM Compound PLA2R ligand ASGPR 5 500 ligand mM µM AGN303 [WQDKGIFVIQSESLKK(CIQAGKSVLTLENKC)K](bic 31-mer) ⍺GN3 + - ABT301 [WQDKGIFVIQSESLKK(CIQAGKSVLTLENKC)K](bic 31-mer) None + - ABT309** VIQSESLKK(CIQAGKSVLTLENKC)K None + - ABT310** VIQSES [SEQ ID NO: 10] None + - ABT311** SVLTENCK [SEQ ID NO: 11] None + - ** Insoluble at 5 mM [00381] The inventors successfully completed a proliferation and cytotoxicity assay using bifunctional degraders. [00382] The inventors will be performing assays of PBMC cytokine release using standard assays known to persons having ordinary skill in the art. EXAMPLE 2 Depletion of anti-PLA2R antibody in vivo. [00383] The inventors are demonstrating the ability of the degraders to deplete anti-PLA2R antibody in vivo using the in vitro-validated anti-PLA2R degraders. [00384] The inventors measured depletion of anti-PLA2R antibody in mice using in vitro-validated anti-PLA2R bifunctional degraders. The inventors have successfully completed assays of murine tolerability of the degraders. [00385] The inventors are proceeding with assays of mouse pharmacokinetics/ pharmacodynamics. Mouse pharmacokinetics/ pharmacodynamics studies were run using AGN303 (⍺GN3) and AGN302 (βGN3). Mice were dosed at 0.1 mg/kg rabbit anti-PLA2R antibody (commercially available antibody that binds to the 31-mer). Degraders were dosed at 0.3 or 1 mg/kg, intravenous or subcutaneous. Degraders rapidly depleted anti-PLA2R from plasma for all doses tested. An antibody rebound effect was observed at four-eight hours.

107 30124-WO-PCT EXAMPLE 3 Mouse maximum tolerated dose (MTD). [00386] AGN303 (⍺GN3) was better tolerated intravenously than AGN302 (βGN3). Clinical observations at 25 and 50 milligram/kilogram were mild and transient. Mice were fully recovered by end of the assay. [00387] AGN303 (⍺GN3)-treated mice showed severe toxic clinical signs at 100 milligram/kilogram (+++) when dosed intravenously: low motility, hunched posture, cyanosis, and coldness. [00388] AGN303 (⍺GN3)-treated mice showed no clinical signs of toxicity up to 100 milligram/kilogram when dosed subcutaneously. EXAMPLE 4 Assays to characterize activities of anti-PLA2R bifunctional degraders. [00377] GN3 sortase reagent. A basic protocol for sortase conjugation including the ASPGR binder for the sortase. C-terminal sortase tag (LPETGG) for conjugation (GN3/linker). [00378] Surface plasmon resonance. Direct binding of anti-PLA2R antibody binding moiety to anti- PLA2R antibody was determined using Biacore™ instruments and IBIS-MX96 systems. Anti-PLA2R antibody was immobilized by amine coupling to the surface of a sensor chip as the ligand. Anti-PLA2R antibody binding moiety is flowed over in solution as analyte. Binding affinity was determined using single-cycle kinetics, e.g., by bio-layer interferometry (ForteBio™oCtet™ systems). TABLE 11 aPLA2R Theoretical Immobili- Experimental Theoretical Active SPR SCK binding zation (RU) Rmax (RU) Rmax (RU) Surface KD (nM) ratio Peptides ABT305 6.9 0.96 ABT301 0.26 0.92 ABT309 No binding Degraders AGN306 22.7 0.80 AGN306 32.7 0.40 AGN306 23.5 0.75 AGN308 51.6 0.27 AGN308 6.72 0.81 AGN308 9.45 0.86 AGN308 15.7 0.26 AGN308 9.64 0.41

108 30124-WO-PCT TABLE 11 Compound aPLA2R Theoretical Immobili- Experimental Theoretical Active SPR SCK binding zation (RU) Rmax (RU) Rmax (RU) Surface KD (nM) ratio AGN308 14.4 0.28 AGN307 27.8 0.37 AGN307 41.8 0.27 AGN309 17.8 0.26 AGN310 45.5 0.27 AGN302 11.9 0.81 AGN302 7.86 0.43 AGN304 2.75 AGN304 3.17 AGN303 7.69 AGN303 6.34 AGN364* 136 2:1 416.8 38.5 124.7 0.31 AGN364* 219 2:1 454 37.2 135.8 0.27 AGN365* 959 2:1 416.8 39.6 249.6 0.16 AGN365* 661 2:1 454 49 271.9 0.18 AGN579* 451 1:1 382 55.5 358 0.16 AGN579* 1240 1:1 429 36.8 402 0.09 AGN579* 1150 1:1 418 41.1 392 0.10 *Ligand: Boster Bio pAb [00379] GN3-maleimide reagent (maleimide-GN3/linker), with a C-terminal Cys for conjugation. [00380] Biophysical/biochemical potency assay to measure target-engagement. A biomolecule coupled to surface of sensor chip as ligand. As analyte is flowed in solution over immobilized ligand, binding to the sensor chip surface induces a change in refractive index proportional to bound mass. [00381] ASGPR-dependent uptake assay. An HEK293 fluorescent cell-based assay was used to assess antibody uptake by cells in vitro. This on-mechanism endocytosis assay measures the anti-PLA2R antibody accumulation in HEK293 cells. [00382] Other off-target assays include measurement of cytotoxicity through In vitro toxicity with HEPG2 cells, e.g., in a CellTiter-Glo assay, measurement of hemagglutination by red blood cell interactions, measurement of PMBC, and measurement of off-target bindings in a house C-type lectin panel. Signal is boosted in the HEK293 versus HepG2 cells when measuring signal accumulation not degradation. Western assays can measure the degradation in HEK cells and other cell lines. [00383] Ternary complex formation. Formation of a ternary complex of anti-PLA2R antibody and ASGPR mediated by anti-PLA2R bifunctional molecules was determined.

109 30124-WO-PCT TABLE 12 Degrader Ternary Complex HTRF (max Ternary Complex [degrader] Ternary Complex EC₅₀ signal:noise) at max signal (nM) (nM) AGN306 9.2 78 5.6 AGN306 6.9 39 2.6 AGN306 5 78 2.3 AGN308 33.4 19 2.8 AGN308 27.6 19 2.3 AGN307 13.5 19 1.3 AGN307 12 39 0.9 AGN309 17.1 39 AGN309 15.1 78 1.3 AGN310 3.7 156 AGN310 3.5 156 5.2 AGN302 7.5 2.5 AGN302 6.1 9 2 AGN304 35.3 5 0.9 AGN304 30 9 1 AGN303 16.9 5 0.7 AGN303 14.3 19 1.3 [00384] Animal models. Testing for antidrug antibodies (ADA) can be done in mouse models. See Meyer-Schwesinger et al., Kidney International, 97(5), 913-919 (2020). Many of the ADAs are IgG4 , such as those in Factor 8 hemophilia. EXAMPLE 5 Preparation of TBT307 - A Preparation of Building block #1: Preparation of Intermediate-26: g, HBr, 1000 mL in total) was stirred at 140°C for sixteen hours. The solvent was removed at 70°C under reduced pressure. The residue was triturated in MeCN (50 mL) for ten minutes. After filtration, the solid was dried under lyophilization to afford Intermediate-26 (100.0 g, 427.9 mmol, 88.4% yield, HBr salt) as a brown solid.¹H

110 30124-WO-PCT NMR (400 MHz, DMSO-d₆) δ ppm 10.03 (s, 1 H) 8.20 (s, 3 H) 7.32 (dd, J = 12.17, 1.88 Hz, 1 H) 7.11 (dd, J = 8.28, 1.51 Hz, 1 H) 6.95-7.03 (m, 1 H) 3.93 (q, J = 5.27 Hz, 2 H). Preparation of Intermediate-27: salt), Reactant 26a (111.1 g, 270.2 mmol, 1.00 equivalent), DIEA (34.9 g, 270.2 mmol, 47.0 mL, 1.00 equivalent) and HOBt (54.7 g, 405.3 mmol, 1.50 equivalents) in DMF (1 L) was added EDCI (56.7 g, 297.2 mmol, 1.10 equivalents) at 20^oC. The mixture was stirred at 20°C for three hours. The mixture was precipitated with 0.5 M HCl (cold, 10 L). After filtration, the solid was dissolved in DCM (2 L), washed with 0.5 M HCl (800 mL), water (800 mL), brine (800 mL), dried over anhydrous Na₂SO₄ and concentrated under reduced pressure. The residue was purified by silica gel column (DCM/methanol = from 1/0 to 20/1) to afford Intermediate-27 (120.0 g, 90% purity, containing a little DMF, 83.3% yield) as a white solid.¹H NMR (400 MHz, DMSO-d₆) δ ppm 9.70 (s, 1 H) 8.34 (t, J = 5.77 Hz, 1 H) 7.90 (d, J = 7.53 Hz, 2 H) 7.71 (d, J = 7.53 Hz, 2 H) 7.61 (d, J = 8.28 Hz, 1 H) 7.39-7.47 (m, 2 H) 7.29-7.36 (m, 2 H) 7.02 (d, J = 12.30 Hz, 1 H) 6.85-6.92 (m, 2 H) 4.20-4.39 (m, 4 H) 4.11-4.19 (m, 2 H) 1.36 (s, 9 H). Preparation of Building block #1: [00387] A mixture of Intermediate-27 (120.0 g, 224.4 mmol, 1.00 equivalent) in trifluoroacetic acid (600 mL) and DCM (600 mL) was stirred at 20°C for one half hour. The solvent was removed under reduced pressure. The residue was purified by silica gel column (DCM/methanol = from 1/0 to 10/1) to afford Building block #1 (100.0 g, 93.5% purity, 93.1% yield) as a white solid.¹H NMR (400 MHz, DMSO- d₆) δ ppm 9.69 (s, 1 H) 8.34 (t, J = 5.90 Hz, 1 H) 7.90 (d, J = 7.28 Hz, 2 H) 7.71 (d, J = 7.53 Hz, 2 H) 7.54 (d, J = 6.53 Hz, 1 H) 7.42 (t, J = 7.40 Hz, 2 H) 7.27-7.37 (m, 1 H) 7.27-7.37 (m, 1 H) 7.02 (d, J = 12.05 Hz, 1 H) 6.82-6.93 (m, 2 H) 4.35-4.43 (m, 1 H) 4.20-4.31 (m, 3 H) 4.13-4.19 (m, 2 H).

111 30124-WO-PCT EXAMPLE 6 Preparation of TBT307 – B Preparation of Intermediate-30: [00389] (1) Resin preparation: To the vessel containing CTC resin (2.0 g, 2.0 mmol, 1.00 mmol/g) and Fmoc-Thr(tBu)-OH (795 mg, 2.0 mmol, 1.00 equivalent) in DCM (50 mL) was added DIEA (4.00 equivalents) dropwise and mixed for two hours with nitrogen gas bubbling at 25°C. Then methanol (2 mL) was added and bubbled with nitrogen gas for another thirty minutes. The resin was washed with DMF (100 mL) * 5, followed by the addition of 20% piperidine in DMF (100 mL) and bubbled with nitrogen gas for thirty minutes at 25°C for Fmoc deprotection. The mixture was filtered. The resin was washed with DMF (100 mL) * 5 before proceeding to next step. [00390] (2) Coupling: A solution of Fmoc-Cys(Trt)-OH (3.51 g, 6.0 mmol, 3.00 equivalents), HBTU (2.16 g, 5.7 mmol, 2.85 equivalents) in DMF (50 mL) was added to the resin with nitrogen gas bubbling. Then DIEA (6.00 equivalents) was added to the mixture dropwise and bubbled with nitrogen gas for thirty minutes at 25°C. The coupling reaction was monitored by ninhydrin test, if it showed colorless, the coupling was completed. The resin was then washed with DMF (100 mL) * 5.

112 30124-WO-PCT [00391] (3) Deprotection: 20% piperidine in DMF (100 mL) was added to the resin and the mixture was bubbled with nitrogen gas for thirty minutes at 25°C. The resin was then washed with DMF (100 mL) * 5. [00392] (4) Steps 2 and 3 were repeated for the following amino acids elongation: Number # 3-15, TABLE 13. [00393] (5) After all the steps were completed, the resin was washed with DMF (100 mL) * 5, methanol (100 mL) * 5, then dried under reduced pressure to afford resin-bound peptide Intermediate- 28 (CTC resin, 2.0 mmol). TABLE 13 List of amino acids and the corresponding reagents used on solid-phase peptide synthesis # Materials Coupling reagents 1 Fmoc-Thr(tBu)-OH (3.00 equivalents) DIEA (4.00 equivalents) 2 Fmoc-Cys(Trt)-OH (3.00 equivalents) HBTU (2.85 equiv.) and DIEA (6.00 equiv.) 3 Fmoc-Trp-OH (3.00 equivalents) HBTU (2.85 equiv.) and DIEA (6.00 equiv.) 4 Fmoc-Val-OH (3.00 equivalents) HBTU (2.85 equiv.) and DIEA (6.00 equiv.) 5 Fmoc-Leu-OH (3.00 equivalents) HBTU (2.85 equiv.) and DIEA (6.00 equiv.) 6 Fmoc-Glu(OtBu)-OH (3.00 equivalents) HBTU (2.85 equiv.) and DIEA (6.00 equiv.) 7 Fmoc-Gly-OH (3.00 equivalents) HBTU (2.85 equiv.) and DIEA (6.00 equiv.) 8 Fmoc-Leu-OH (3.00 equivalents) HBTU (2.85 equiv.) and DIEA (6.00 equiv.) 9 Building block #1 (2.00 equivalents) DIC (2.00 equiv.) and HOBt (2.00 equiv.) 10 Fmoc-Trp-OH (3.00 equivalents) DIC (3.00 equiv.) and HOBt (3.00 equiv.) 11 Fmoc-Ala-OH (3.00 equivalents) DIC (3.00 equiv.) and HOBt (3.00 equiv.) 12 Fmoc-Cys(Trt)-OH (3.00 equivalents) DIC (3.00 equiv.) and HOBt (3.00 equiv.) 13 Fmoc-Asp(OtBu)-OH (3.00 equivalents) DIC (3.00 equiv.) and HOBt (3.00 equiv.) 14 AC Ac₂O:NMM:DMF=10:5:85 15 Boc-PEG₂-OH (3.00 equivalents) DIC:HOBt:DMAP=3:3:3 Peptide cleavage and cyclization: [00394] (1) Cleavage solution (trifluoroacetic acid/TIS/water, 95/2.5/2.5, v/v/v, 500 mL) was added to the flask containing the side-chain protected resin-bound peptide (CTC resin, 5 g, 2.0 mmol) at 25^oC and stirred for two hours. [00395] (2) After filtration, the filtrate was collected.

113 30124-WO-PCT [00396] (3) The filtrate was precipitated with cold isopropyl ether (2.5 L). After filtration, the solid was washed with isopropyl ether (2.5 L) twice, and the crude peptide was dried under reduced pressure for two hours to afford Intermediate-29 (3.0 g, crude) as a white solid. [00397] To the mixture of Intermediate-29 (3.0 g, crude) in HOAc/MeCN/water (4/3/3, v/v/v, 2 L) was added 0.1 M I₂/AcOH dropwise until a yellow color persisted, then the mixture was stirred at 25^oC for five minutes. The mixture was quenched by addition of 0.1 M aq. Na₂S₂O₃ dropwise until the yellow color disappeared. After filtration, the filtrate was purified by prep-high performance liquid chromatography (A: 0.075% trifluoroacetic acid/water, B: MeCN), followed by lyophilization to afford Intermediate-30 (360 mg, 90.0% purity, 50.8% yield) as a white solid. LCMS: retention time = 0.907=0.960 minutes, MS calculated: M_av = 1833.02, mass observed: [M + 2H]²⁺ =917.00, [M + H]⁺ =1832.91. Preparation of Intermediate-31: of Target A001 (1.2 g, 1.00 equivalent) and DIEA (332.9 mg, 449.9 μL, 3 equivalents) in 10 mL DMF at 0°C. The resulting reaction was stirred for five minutes at 0°C. After completion monitored by LC-MS, the mixture was directly injected into the reverse column, purified by prep-high performance liquid chromatography (A: 0.075% trifluoroacetic acid/water, B: MeCN), followed by lyophilization to afford Intermediate-31 (700 mg, 95.0% purity, 57.5% yield) as colorless oil. LCMS: retention time = 0.709 minutes, MS calculated: Mav = 1821.81, mass observed: [M+16 + 3H]³⁺ =613.10.

114 30124-WO-PCT Preparation of TBT307: Intermediate-31 (140 mg, 76.85 μmol, 1.00 equivalent) in DMF (2 mL) was added DIEA (29.80 mg, 230.54 μmol, 40.16 μL, 3.00 equivalents). The mixture was stirred at 20°C for one hour. After completion monitored by LC-MS, the mixture was acidified by 1 M HCl to pH = 5. The mixture was purified by prep- high performance liquid chromatography (A: 0.075% trifluoroacetic acid/water, B: MeCN) directly, followed by lyophilization to afford TBT307 (103 mg, 92.8% purity, 35.6% yield.) as a white solid. LCMS: retention time = 1.391 minutes, MS calculated: M_av = 3488.76, mass observed: [M + 3H]³⁺ =1163.90. EXAMPLE 7 Procedure for Preparation of Intermediate-27: Preparation of Intermediate-2: added THF (40 mL) slowly, then a solution of trifluoroacetic acid (7.44g, 65.2 mmol, 4.86 mL, one equivalent) and Intermediate-1 (40.0 g, 65.2 mmol, 1.00 equivalent) in THF (360 mL) was added to the reaction slowly under nitrogen gas. The reaction was degassed and purged with argon gas and hydrogen gas for three times, then stirred at 25°C for three hours under hydrogen gas atmosphere (40 psi). TLC (DCM: methanol = 10: 1, R_f = 0.20) indicated Intermediate-1 was consumed completely, and one major new spot with larger polarity was detected. The reaction mixture was dissolved in THF (100 mL), filtered carefully through siliceous earth under nitrogen gas atmosphere, the cake was washed with THF (100 mL

115 30124-WO-PCT * 2), and the filtrate was concentrated under reduced pressure to get Intermediate-2 (38.7 g, 38.5 mmol, 59.0% yield, 59.0% purity, trifluoroacetic acid salt) as a white solid. LCMS: retention time = 0.428 minutes, MS calculated: 478.22, mass observed: [M + Na]⁺ = 501.2.¹H NMR (400 MHz, DMSO-d6) δ ppm 7.79-7.91 (m, 3 H), 5.16-5.28 (m, 1 H), 4.97 (br dd, J = 11.07, 2.81 Hz, 1 H), 4.54 (br d, J = 8.50 Hz, 1 H), 4.03 (s, 2 H), 3.77-3.93 (m, 2 H), 3.53-3.62 (m, 8 H), 2.98 (br d, J = 5.00 Hz, 2 H), 2.10 (s, 3 H), 2.00 (s, 3 H), 1.89 (s, 3 H), 1.78 (s, 3 H). Preparation of Intermediate-4: Intermediate-2 (38.1 g, 64.3 mmol, 4.00 equivalents, trifluoroacetic acid salt) in DMF (17 mL) and DCM (340 mL) was added HOBT (8.69 g, 64.3 mmol, 4.00 equivalents), EDCI (12.3 g, 64.3 mmol, 4.00 equivalents) and DIEA (9.35 g, 72.3 mmol, 4.50 equivalents) successively. The reaction was stirred at 25°C for two hours. TLC (DCM: methanol = 10: 1, Rf = 0.5) indicated Intermediate-3 was consumed completely, and one major new spot with larger polarity was detected. The reaction mixture was slowly poured into a stirring cold 1.0 mol/L HCl solution (350 mL) and stirred for ten minutes. A white precipitate formed and was filtered. The aqueous phase was extracted with DCM (350 mL* 2) twice. The combined organic layers were washed with sat. NaHCO₃ (350 mL), dried over Na₂SO₄, and concentrated under reduced pressure to get a residue. The residue was purified by column chromatography (SiO₂, DCM:methanol = 100: 1 to 15: 1) to afford Intermediate-4 (22.0 g, 10.6 mmol, 66.0% yield, 92.2% purity) as a white solid.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.91 (br t, J = 5.32 Hz, 3 H), 7.81 (d, J = 9.26 Hz, 3 H), 7.26-7.49 (m, 6 H), 7.12 (s, 1 H), 5.21 (d, J = 3.25 Hz, 3 H), 5.02 (s, 2 H), 4.97 (dd, J = 11.13, 3.25 Hz, 3 H), 4.55 (d, J = 8.38 Hz, 3 H), 4.03 (s, 9 H), 3.84-3.92 (m, 3 H), 3.74-3.82 (m, 3 H), 3.47-3.65 (m, 38 H), 3.39 (br s, 3 H), 3.20 (q, J = 5.42 Hz, 6 H), 2.30 (br t, J = 6.13 Hz, 6 H), 2.10 (s, 9 H), 1.99 (s, 9 H), 1.89 (s, 9 H), 1.77 (s, 9 H). LCMS: retention time = 0.403 minutes, MS calculated: 1908.81, mass observed: [M + 2H]²⁺ = 1910.2.

116 30124-WO-PCT Preparation of Intermediate-5: Pd/C (1.60 g, 1.50 mmol, 10% purity, 0.17 equivalents) carefully. Then THF (60.0 mL) was added to infiltrate the Pd/C completely, followed by the solution of Intermediate-4 (16.4 g, 8.59 mmol, 1.00 equivalent) and trifluoroacetic acid (979 mg, 8.59 mmol, 637.8 μL, 1.00 equivalent) in THF (100 mL) slowly under argon gas atmosphere. The resulting mixture was degassed and purged with hydrogen gas for three times, and then the mixture was stirred at 25°C for three hours under hydrogen gas atmosphere (15 psi). TLC (DCM:methanol = 10: 1, Rf = 0.6) indicated Intermediate-9 was consumed completely, and one major new spot was detected. The reaction mixture was filtered carefully through siliceous earth under nitrogen gas atmosphere, the cake was washed with THF (50 mL*2). The filter cake was added water immediately. The organic layer concentrated under reduced pressure to afford Intermediate-5 (15.7 g, 6.78 mmol, 78.9% yield, 81.6% purity, trifluoroacetic acid salt) as a white solid. ¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.91-7.98 (m, 5 H), 7.82 (br d, J = 9.13 Hz, 3 H), 7.74 (s, 1 H), 7.12- 7.28 (m, 1 H), 5.22 (br d, J = 2.63 Hz, 3 H), 4.97 (br dd, J = 11.13, 2.75 Hz, 3 H), 4.54 (d, J = 8.51 Hz, 3 H), 3.84-3.93 (m, 3 H), 3.78 (br dd, J = 10.13, 4.88 Hz, 3 H), 3.53-3.62 (m, 22 H), 3.33-3.45 (m, 22 H), 3.18- 3.25 (m, 6 H), 2.31 (br t, J = 6.13 Hz, 6 H), 2.10 (s, 9 H), 2.00 (s, 9 H), 1.89 (s, 9 H), 1.73-1.81 (m, 14 H). LCMS: retention time = 0.341 minutes, MS calculated: 1774.7, found: [M + 2H]²⁺ = 1776.9. Preparation of Target-A001A:

117 30124-WO-PCT [00403] To a solution of Intermediate-5 (5.5 g, 2.91 mmol, 1.00 equivalent, trifluoroacetic acid) in methanol (50.0 mL) was added NaOMe (707 mg, 13.1 mmol, 4.50 equivalents) at 0°C. The mixture was stirred at 0°C for 0.5 hour. The reaction was monitored by LCMS, which showed the desired mass (one main peak with desired was detected.). The reaction mixture was added with 1.0 M HCl solution till the pH = 6. The mixture was diluted with water (75.0 mL) and extracted with DCM (120 mL * 3). The mixture was freeze-dried to afford Target-A001A (4.1 g, 2.74 mmol, 94.1% yield, 93.4% purity, HCl) as a white solid.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.94 (br t, J = 5.50 Hz, 3 H), 7.62 (d, J = 9.01 Hz, 3 H), 7.54 (s, 1 H), 4.28 (d, J = 8.50 Hz, 3 H), 3.70-3.88 (m, 6 H), 3.61-3.70 (m, 6 H), 3.49-3.57 (m, 31 H), 3.38-3.43 (m, 12 H), 3.31 (br d, J = 6.25 Hz, 4 H), 3.17 (s, 6 H), 3.09 (s, 2 H), 2.30 (br t, J = 6.32 Hz, 6 H), 1.80 (s, 9 H). LCMS: retention time = 0.22 minutes, MS calculated: 1396.6, found: [M + H]⁺ = 1397.8. Preparation of Intermediate-27: CH2CO2-NHS (567 mg, 1.71 mmol, 1.20 equivalents) in DMF (20 mL) was added DIEA (554 mg, 4.29 mmol, 709 μL, 3.00 equivalents) at 0°C. The mixture was stirred at 0°C for two hours under nitrogen gas atmosphere. LCMS indicated Target-A001A was consumed completely, one main peak with desired MS was detected. The residue was purified by prep-high performance liquid chromatography (AcOH condition) directly to afford Intermediate-27 (1.75 g, 1.04 mmol, 73.2% yield, 96.5% purity) as a white solid. LCMS: retention time = 0.286 minutes, MS calculated: M_av = 1612.68, [M + 2H]²⁺ = 807.1, [M-sugar + 2H]²⁺ = 705.6.

118 30124-WO-PCT EXAMPLE 8 Procedure for Preparation of TBT544: Preparation of Intermediate-37: [00405] Peptide was synthesized using standard Fmoc chemistry (C resin). [00406] (1) Resin preparation: DMF (100 mL) was added to the vessel containing Rink MBHA-Amide Resin (5.00 mmol, 16.7 g, 0.30 mmol/g) with nitrogen gas bubbling for thirty minutes. The resin was washed with DMF (100 mL * 5), followed by adding 20% piperidine in DMF (50 mL) and bubbled with nitrogen gas for thirty minutes at 25°C for Fmoc deprotection. The mixture was filtered. The resin was washed with DMF (100 mL * 5) before proceeding to next step. [00407] (2) Coupling: A solution of Fmoc-Pra-OH (3.00 equivalents), HATU (2.85 equivalents) in DMF (50 mL) was added to the resin with nitrogen gas bubbling. Then DIEA (6.00 equivalents) was added to the mixture dropwise and bubbled with nitrogen gas for thirty minutes at 25°C. The coupling reaction was monitored by ninhydrin test, if it showed colorless, the coupling was completed. The resin was then washed with DMF (100 mL) * 5. [00408] (3) Deprotection: 20% piperidine in DMF (50 mL) was added to the resin and the mixture was bubbled with nitrogen gas for thirty minutes at 25°C. The resin was then washed with DMF (100 mL) * 5. The deprotection reaction was monitored by ninhydrin test. If it showed blue or brownish red, the reaction was completed. [00409] (4) Steps 2 and 3 were repeated for the following amino acids elongation: Number # 2-3, in TABLE 14. [00410] (5) After the last position completed, the resin was then washed with DMF (100 mL) * 5, methanol (100 mL) * 5, and dried under reduced pressure to afford peptide-bound-resin (5 mmol). TABLE 14 The list of amino acids and the corresponding reagents used on solid-phase peptide synthesis # Materials Coupling reagents 1 Fmoc-Pra-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 2 Fmoc-Gly-Gly-Gly-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 3 Fmoc-Gly-Gly-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.)

119 30124-WO-PCT Peptide TFA deprotection: [00411] Trifluoroacetic acid deprotection: peptide-bound-resin was stirred in a solution of trifluoroacetic acid/3-MPA/Tis/water (92.5/2.5/2.5/2.5, v/v/v/v, 200 mL) at 25°C for two hours. The mixture was precipitated with isopropyl ether (cold, 2 L). After filtration, the solid was washed with isopropyl ether (cold, 2 L) for two additional times, and dried under reduced pressure for two hours to afford Intermediate-37 (620 mg, crude) as a white solid. The crude was purified by prep-high performance liquid chromatography (A: 0.075% trifluoroacetic acid/water, B: MeCN) directly to afford Intermediate-37 (1.59 g, 3.77 mmol, 75.5% yield, 94.3% purity) as a white solid. LCMS: retention time = 0.071 minutes, MS calculated: M_av = 397.39, mass observed: [M + H]⁺ = 398.1. Preparation of TBT544: 27 (1.69 g, 1.04 mmol, 1.00 equivalent) in DMF (10 mL) was added a solution of CuSO₄ (0.4 M, 2.62 mL, 1.00 equivalent), sodium L-ascorbate (0.4 M, 10.4 mL, 4.00 equivalents) at 0°C. The mixture was stirred at 0°C for two hours under nitrogen gas atmosphere. LCMS indicated Intermediate-27 was consumed completely, one main peak with desired MS was detected. The residue was purified by prep-high performance liquid chromatography (AcOH condition) directly to afford TBT544 (1.377 g, 666 μmol, 63.5% yield, 97.3% purity) as a white solid. LCMS: retention time = 1.372 minutes, MS calculated: M_av = 2010.06, [M + 2H]²⁺ = 1005.7, [M + 3H]³⁺ = 671.0, [M -sugar + 2H]²⁺ = 904.2, [M -2sugar + 2H]²⁺ = 802.6.

120 30124-WO-PCT EXAMPLE 9 Procedure for Preparation of Target-A001A: Preparation of Intermediate-2: [00413] (450 mL) was added 1 (34.2 g, 200 mmol, 1.00 equivalent) in 2-Methyltetrahydrofuran (160 mL) at 0°C. The mixture was stirred at 25°C for two hours. TLC (DCM:methanol = 20: 1, R_f = 0.70) showed the reaction was completed, one major new spot with lower polarity was detected. The reaction mixture was added HCl/EA (1 N, 27.0 mL) and stirred for thirty minutes, and the white precipitate was removed by filtration, the filtrate was concentrated under reduced pressure to afford Intermediate-2 (crude, 105.0 g, 370.6 mmol) as yellow oil. LCMS: retention time = 0.797 minutes, MS calculated: 283.14, mass observed: [M + Na]⁺ = 306.1.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.23-7.41 (m, 5 H), 5.01 (s, 2 H), 4.60 (br s, 1 H), 3.45- 3.52 (m, 6 H), 3.38-3.43 (m, 5 H), 3.14 (q, J = 5.94 Hz, 2 H), 2.53-2.55 (m, 1 H). Preparation of Intermediate-3: added TMSOTf (85.6 g, 385 mmol, 1.50 equivalents) and stirred at 60°C for two hours. The reaction was then cooled to room temperature (25°C) and stirred for another one hour. A mixture of Intermediate-2 (80.0 g, 282 mmol, 1.10 equivalents) and 4 Å powder molecular sieves (50.0 g) in DCE (500 mL) was added to the reaction. The resulting mixture was stirred for thirty minutes under nitrogen gas atmosphere. Then a solution of Intermediate-2a (100.0 g, 257 mmol, 1.00 equivalent) in DCE was added dropwise to the mixture at 0°C. The mixture was stirred for sixteen hours at 25°C under nitrogen gas atmosphere. TLC (DCM:methanol = 10: 1, R_f = 0.42) indicated Intermediate-2a was consumed

121 30124-WO-PCT completely, and one major new spot with larger polarity was detected. The reaction mixture was filtered and washed with sat. NaHCO₃ (500 mL), water (500 mL) and brine (500 mL). The organic layer was dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, PE: EA = 3: 1 to 1: 6, then DCM:methanol = 20: 1) to afford Intermediate-3 (90.0 g, 146.9 mmol, 91.6% purity, 57.2% yield) as yellow oil. LCMS: retention time = 0.860 minutes, MS calculated: 612.25, mass observed: [M + H]⁺ = 613.2.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.80 (d, J = 9.03 Hz, 1 H), 7.24-7.39 (m, 6 H), 5.22 (d, J = 3.51 Hz, 1 H), 4.95-5.05 (m, 3 H), 4.53-4.59 (m, 1 H), 3.99-4.06 (m, 3 H), 3.84-3.92 (m, 1 H), 3.73-3.82 (m, 1 H), 3.55-3.61 (m, 1 H), 3.45- 3.53 (m, 7 H), 3.41 (t, J = 5.90 Hz, 2 H), 3.11-3.18 (m, 3 H), 2.10 (s, 3 H), 1.99 (s, 3 H), 1.89 (s, 3 H), 1.77 (s, 3 H). Preparation of Intermediate-4: [00415] Pd/C (9.00 g, 10% purity) in reaction bottle (purged with argon gas three times) was added THF (180 mL) slowly, then a solution of trifluoroacetic acid (16.7 g, 147 mmol, 1.00 equivalent) and Intermediate-3 (90.0 g, 147.0 mmol, 1.00 equivalent) in THF (720 mL) was added to the reaction slowly under nitrogen gas. The reaction was degassed and purged with nitrogen gas and hydrogen gas for three times, then stirred at 25°C for three hours under hydrogen gas atmosphere (40 psi). TLC (DCM:methanol = 10: 1, R_f = 0.20) indicated Intermediate-3 was consumed completely, and one major new spot with larger polarity was detected. The reaction mixture was dissolved in THF (100 mL), filtered carefully through siliceous earth under nitrogen gas atmosphere, the cake was washed with THF (100 mL * 2), and the filtrate was concentrated under reduced pressure to get the residue. The residue was diluted with water (1000 mL), washed with DCM (300 mL * 3), the aqueous layer was lyophilized to afford Intermediate-4 (80.0 g, 139.0 mmol, 95.1% purity, 91.8% yield, trifluoroacetic acid salt) as a white solid. LCMS: retention time = 0.484 minutes, MS calculated: 478.22, mass observed: [M + H]⁺ = 478.9.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.91 (br t, J = 9.03 Hz, 4 H), 5.21 (d, J = 3.26 Hz, 1 H), 4.96 (dd, J = 11.17, 3.39 Hz, 1 H), 4.54 (d, J = 8.53 Hz, 1 H), 3.98-4.08 (m, 3 H), 3.85-3.93 (m, 1 H), 3.75-3.84 (m, 1 H), 3.59 (br t, J = 5.14 Hz, 3 H), 3.50-3.56 (m, 6 H), 2.98 (br s, 2 H), 2.10 (s, 3 H), 2.00 (s, 3 H), 1.89 (s, 3 H), 1.78 (s, 3 H).

122 30124-WO-PCT Preparation of Intermediate-6: aqueous NaOH (5.0 M, 9.91 mL, 0.10 equivalents) dropwise at 0-15°C for over five minutes. After addition, the mixture was stirred at 0-15°C for five minutes, then 5a (254.0 g, 1.98 mol, 287 mL, 4.00 equivalents) was added to the reaction mixture dropwise at 20°C. The resulting mixture was stirred at 25°C for sixteen hours. TLC (DCM:methanol = 10: 1, R_f = 0.7) indicated Intermediate-5 was consumed completely, and one major new spot with lower polarity was detected. The resulting reaction mixture was concentrated under reduced pressure to give a residue. The residue was dissolved in ethyl acetate (400 mL), quenched by addition of water (400 mL), and extracted with ethyl acetate (400 mL * 3). The combined organic layers were washed with brine (300 mL * 2), dried over Na₂SO₄, filtered and concentrated under reduced pressure to afford Intermediate-6 (100.0 g, 197.8 mmol, 96.0% purity, 40.0% yield) as colorless oil.¹H NMR (400 MHz, DMSO-d₆) δ ppm 3.51-3.61 (m, 7 H), 3.17 (s, 5 H), 2.39 (t, J = 6.02 Hz, 6 H), 1.40 (s, 27 H). Preparation of Intermediate-7: added HOBt (10.7 g, 79.1 mmol, 1.00 equivalent). Then 6a (16.5 g, 79.1 mmol, 1.00 equivalent) and DCC (16.3 g, 79.1 mmol, 1.00 equivalent) were added. The reaction was stirred at 25°C for sixteen hours. TLC (PE: EA = 1: 1, R_f = 0.80) indicated Intermediate-6 was consumed completely, and one major new spot with lower polarity was detected. MeCN was evaporated to get the residue. The residue was purified by

123 30124-WO-PCT column chromatography (SiO₂, PE: EA = 10: 1 to 1: 1) to afford Intermediate-7 (40.0 g, 57.4 mmol, 82.9% purity, 72.5% yield) as a white solid. LCMS: retention time = 1.151 minutes, MS calculated: 696.38, mass observed: [M + H]⁺ = 697.3, [M + Na]⁺ = 719.3.¹H NMR (400 MHz, DMSO-d6) δ ppm 7.26-7.40 (m, 6 H), 7.06 (s, 1 H), 5.03 (s, 2 H), 3.49-3.61 (m, 14 H), 2.39 (br t, J = 6.02 Hz, 6 H), 1.40 (s, 27 H). Preparation of Intermediate-8: [00418] A solution of Intermediate-7 (30.0 g, 43.0 mmol, 1.00 equivalent) in HCOOH (300 mL) was stirred at 25°C for sixteen hours. TLC (PE: EA = 1: 1, R_f = 0.04) indicated Intermediate-7 was consumed completely, and one major new spot with larger polarity was detected. Solvent was evaporated under reduced pressure, then co-evaporated with toluene (50 mL * 3) under reduced pressure and dried under reduced pressure to get the residue. The residue was purified by prep-high performance liquid chromatography (A: 0.1% FA condition/water, B: MeCN) to afford Intermediate-8 (20.0 g, 37.8 mmol, 98.2% purity, 87.9% yield).¹H NMR (400 MHz, DMSO-d₆) δ ppm 12.17 (br s, 3 H), 7.26-7.43 (m, 6 H), 7.06 (s, 1 H), 5.02 (s, 2 H), 3.49-3.65 (m, 14 H), 2.42 (br t, J = 6.27 Hz, 6 H). LCMS: retention time = 0.790 minutes, MS calculated: 528.20, mass observed: [M + H]⁺ = 529.2. Preparation of Intermediate-9: [00419] To a stirring solution of Intermediate-8 (20.0 g, 37.8 mmol, 1.00 equivalent) and Intermediate-4 (78.5 g, 132 mmol, 3.50 equivalents, trifluoroacetic acid salt) in DMF (400 mL) was

124 30124-WO-PCT added HOBT (20.4 g, 151 mmol, 4.00 equivalents), EDCI (29.0 g, 151 mmol, 4.00 equivalents) and DIEA (22.0 g, 170 mmol, 4.50 equivalents) successively. The reaction was stirred at 25°C for two hours. TLC (DCM:methanol = 10: 1, Rf = 0.4) indicated Intermediate-8 was consumed completely, and one major new spot with larger polarity was detected. The reaction mixture was slowly poured into a stirring cold 0.5 mol/L HCl solution (900 mL) and stirred for ten minutes. White precipitate formed and was filtered. The aqueous phase was extracted with DCM (600 mL* 2) twice. The combined organic layers were washed with 5% NaHCO₃ (450 mL), dried over Na₂SO₄, and concentrated under reduced pressure to get a residue. The residue was purified by column chromatography (SiO₂, DCM:methanol = 100: 1 to 5: 1) to afford Intermediate-9 (58.0 g, 30.4 mmol, 82.7% purity, 80.3% yield) as a white solid.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.92 (br t, J = 5.14 Hz, 3 H), 7.81 (d, J = 9.03 Hz, 3 H), 7.28-7.39 (m, 6 H), 7.13 (s, 1 H), 5.21 (d, J = 3.26 Hz, 3 H), 5.02 (s, 2 H), 4.97 (dd, J = 11.17, 3.39 Hz, 3 H), 4.54 (d, J = 8.53 Hz, 3 H), 4.03 (s, 9 H), 3.84-3.92 (m, 3 H), 3.75-3.81 (m, 3 H), 3.45-3.61 (m, 37 H), 3.39 (br s, 3 H), 3.18-3.23 (m, 6 H), 2.30 (br t, J=6.15 Hz, 6 H), 2.10 (s, 9 H), 2.00 (s, 9 H), 1.89 (s, 9 H), 1.77 (s, 9 H). LCMS: retention time = 3.455 minutes, MS calculated: 1908.81, mass observed: [M + 2H]²⁺ = 955.7. Preparation of Intermediate-10: [00420] The 500 mL round-bottom flask was purged with argon gas three times and added dry Pd/C (1.50 g, 1.41 mmol, 10% purity, 1.00 equivalent) carefully. Then THF (150.0 mL) was added to infiltrate the Pd/C completely, followed by the solution of Intermediate-9 (15.0 g, 7.85 mmol, 1.00 equivalent) and trifluoroacetic acid (895 mg, 7.85 mmol, 583 μL, 1.00 equivalent) in tetrahydrofuran (75 mL) slowly under argon gas atmosphere. The resulting mixture was degassed and purged with hydrogen gas for three times, and then the mixture was stirred at 25°C for three hours under hydrogen gas atmosphere (15 psi). The reaction was monitored by LCMS. LCMS showed the desired mass. One main peak with desired was detected. The reaction mixture was filtered carefully through siliceous earth under nitrogen gas atmosphere, the cake was washed with THF (100 mL*2). The filter cake was added water immediately. The organic layer concentrated under reduced pressure to afford Intermediate-10 (13.0 g,

125 30124-WO-PCT 6.54 mmol, 83.2% yield, 99.7% purity, trifluoroacetic acid salt) as a white solid.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.89-7.99 (m, 5 H), 7.82 (d, J = 9.3 Hz, 3 H), 7.74 (s, 1 H), 7.14-7.28 (m, 1 H), 5.22 (d, J = 3.3 Hz, 3 H), 4.97 (dd, J = 11.3, 3.4 Hz, 3 H), 4.54 (d, J = 8.5 Hz, 3 H), 3.84-3.93 (m, 3 H), 3.76-3.82 (m, 3 H), 3.47-3.61 (m, 43 H), 3.21 (q, J = 5.8 Hz, 6 H), 2.29-2.34 (m, 6 H), 2.10 (s, 9 H), 2.00 (s, 9 H), 1.89 (s, 8 H), 1.77 (s, 9 H). LCMS: retention time = 1.333 minutes, MS calculated: 1774.7, found: [M + 2H]²⁺ = 888.6. Preparation of Target-A001A: in methanol (120.0 mL) was added NaOMe (5.4 M, 5.01 mL, 4.26 equivalents) at 0°C. The mixture was stirred at 0°C for 0.5 h. The reaction was monitored by LCMS, LCMS showed the desired mass (one main peak with desired was detected.). The reaction mixture was added with 1.0 M HCl solution (10.0 mL) till the pH = 6. The mixture was diluted with water (75.0 mL) and extracted with DCM (120 mL * 3). The mixture was freeze-dried to afford Target-A001A (9.0 g, 5.96 mmol, 93.9% yield, >95% purity, HCl) as a white solid.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.96 (br t, J = 5.4 Hz, 3 H), 7.67 (d, J = 8.9 Hz, 3 H), 7.51 (s, 1 H), 4.27 (d, J = 8.4 Hz, 3 H), 3.75-3.80 (m, 6 H), 3.70 (br d, J = 10.0 Hz, 6 H), 3.49 (br d, J = 4.0 Hz, 31 H), 3.37-3.42 (m, 12 H), 3.30 (br d, J = 6.1 Hz, 4 H), 3.20 (br d, J = 5.8 Hz, 6 H), 2.99 (s, 2 H), 2.30 (br t, J = 6.4 Hz, 6 H), 1.80 (s, 9 H). LCMS: retention time = 0.966 minutes, MS calculated: 1396.6, found: [M + 2H]²⁺ = 699.1.

126 30124-WO-PCT EXAMPLE 10 Procedure for Preparation of AGN306: Preparation of Intermediate-17: g, and Fmoc-Lys(Boc)-OH (1.87 g, 4.00 mmol, 1.00 equivalent) in DCM (100 mL) was added DIEA (4.00 equivalents) dropwise and mix for two hours with nitrogen gas bubbling at 25°C. Methanol (20 mL) was added. The mixture was bubbled with nitrogen gas for another thirty minutes. The resin was washed with DMF (100 mL) * 5. Then 20% piperidine in DMF (50 mL) was added and the mixture was bubbled with nitrogen gas for thirty minutes at 25°C. The mixture was filtered to obtain the resin. The resin was washed with DMF (100 mL) * 5 before proceeding to next step. [00424] (2) Coupling: A solution of Fmoc-Cys(Trt)-OH (7.02 g, 12.0 mmol, 3.00 equivalents), HATU (4.33 g, 2.85 equivalents) in DMF (50 mL) was added to the resin with nitrogen gas bubbling. DIEA (6.00 equivalents) was added to the mixture dropwise. The mixture was bubbled with nitrogen gas for thirty minutes at 25°C. The coupling reaction was monitored by ninhydrin test, if it showed colorless, the coupling was completed. The resin was washed with DMF (100 mL) * 5. [00425] (3) Deprotection: 20% piperidine in DMF (50 mL) was added to the resin and the mixture was bubbled with nitrogen gas for thirty minutes at 25°C. The resin was washed with DMF (100 mL) * 5. The deprotection reaction was monitored by ninhydrin test, if it showed blue or brownish red, the reaction was completed. [00426] (4) Steps 2 and 3 were repeated for the following amino acids elongation: Number # 3-31, TABLE 15. [00427] (5) After the last position completed, the resin was washed with DMF (100 mL) * 5, methanol (100 mL) * 5, and dried under reduced pressure to afford Intermediate-11 (peptide-bound- resin, 4.00 mmol, 47.0 g).

127 30124-WO-PCT TABLE 15 The list of amino acids and the corresponding reagents used on solid-phase peptide synthesis # Materials Coupling reagents 1 Fmoc-Lys(Boc)-OH (1.00 equivalent) DIEA (4.00 equivalents) 2 Fmoc-Cys(Trt)-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 3 Fmoc-Asn(Trt)-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 4 Fmoc-Glu(OtBu)-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 5 Fmoc-Leu-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 6 Fmoc-Thr(Trt)-OH (3.00 equivalents) DIC (3.00 equiv.) and HOAt (3.00 equiv.) 7 Fmoc-Leu-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 8 Fmoc-Val-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 9 Fmoc-Lys(Boc)-Ser(psi(Me,Me)pro)-OH HATU (2.85 equiv.) and DIEA (6.00 equiv.) (3.00 equivalents) 10 Fmoc-Gly-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 11 Fmoc-Ala-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 12 Fmoc-Gln(Trt)-OH (3.00 equivalents) DIC (3.00 equiv.) and HOAt (3.00 equiv.) 13 Fmoc-Ile-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 14 Fmoc-Cys(Trt)-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 15 Fmoc-Lys(Boc)-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 16 Fmoc-Lys(Boc)-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 17 Fmoc-Leu-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 18 Fmoc-Ser(tBu)-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 19 Fmoc-Glu(OtBu)-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 20 Fmoc-Ser(tBu)-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 21 Fmoc-Gln(Trt)-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 22 Fmoc-Ile-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 23 Fmoc-Val-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 24 Fmoc-Phe-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 25 Fmoc-Ile-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 26 Fmoc-Gly-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 27 Fmoc-Lys(Boc)-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 28 Fmoc-Asp(OtBu)-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 29 Fmoc-Gln(Trt)-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.)

128 30124-WO-PCT TABLE 15 The list of amino acids and the corresponding reagents used on solid-phase peptide synthesis # Materials Coupling reagents 30 Fmoc-Trp-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 31 Fmoc-Dab(N₃)-OH (1.50 equivalents) DIC (1.50 equiv.) and HOAt (1.50 equiv.) Peptide cleavage and disulfide formation: [00428] 1) (1) TFA deprotection: Intermediate-11 (47.0 g, resin) was stirred in a solution of trifluoroacetic acid/3-MPA/Tis/water (92.5/2.5/2.5/2.5, v/v/v/v, 500 mL) at 25°C for two hours. After filtration, the filtrate was precipitated with isopropyl ether (cold, 5 L). After filtration, the solid was washed with isopropyl ether (cold, 5 L) for two additional times, and dried under reduced pressure for two hours to afford Intermediate-12 (14.0 g, crude) as a white solid. LCMS: retention time = 0.474 minutes, MS calculated: Mav = 3621.19, mass observed: [M + 2H]²⁺ = 1811.0 [M + 3H]³⁺ = 1207.7, [M + 4H]⁴⁺ = 906.1, [M + 5H]⁵⁺ = 725.0, [M + 6H]⁶⁺ = 604.4, [M + 7H]⁷⁺ = 518.3. [00429] 2) (2) Disulfide formation: Intermediate-12 (14.0 g, crude) was dissolved in water (2.8 L) and MeCN (1.2 L) at 25°C. To the mixture was added 0.1 M I₂/AcOH dropwise until a yellow color persisted. Then the mixture was stirred at 25°C for five minutes. After filtration, the filtrate was purified by prep-high performance liquid chromatography (A: 0.075% trifluoroacetic acid/water, B: MeCN) directly to afford Intermediate-17 (1.75 g, 438 μmol, 10.95% yield, 90.26% purity) as a white solid. LCMS: retention time = 0.439 minutes, MS calculated: Mav = 3619.18, mass observed: [M + 2H]²⁺ = 1810.5 [M + 3H]³⁺ = 1207.1, [M + 4H]⁴⁺ = 905.6, [M + 5H]⁵⁺ = 724.6. Preparation of Intermediate-14: [00430] To a solution of Intermediate-13 (600 mg, 2.31 mmol, 1.00 equivalent), Intermediate-13a (2.30 g, 13.8 mmol, 6.00 equivalents) in DMF (6 mL) was added EDCI (1.33 g, 6.92 mmol, 3.00 equivalents) at 0°C. The mixture was stirred at 0°C for one hour. The mixture was purified by prep-high performance liquid chromatography (A: 0.075% trifluoroacetic acid/water, B: MeCN) directly to afford

129 30124-WO-PCT Intermediate-14 (800 mg, 83.4% yield, 98.2 % purity) as yellow oil. LCMS: retention time = 1.4 thirty minutes, MS calculated: Mav = 408.34, mass observed: [M + Na]⁺ = 431.0. Preparation of Target-A001A-PEG4-Alkyne: (1.00 g, 644 μmol, 1.00 equivalent) in DMF (0.25 mL) was added DIEA (166 mg, 230 µl, 2.00 equivalents). The mixture was stirred at 25°C for twelve hours. The mixture was diluted with MeCN/water (cold, v/v, 3/3, 10 mL), then dried by lyophilization to remove DMF. The residue was purified by prep-high performance liquid chromatography (AcOH condition) directly to afford Target-A001A-PEG4-Alkyne (0.60 g, 56.8% yield, 93.5% purity) as colorless oil. LCMS: retention time = 0.368 minutes, MS calculated: Mav = 1639.74, mass observed: [M + H]⁺ = 1639.8, [M-sugar + H]⁺ = 1426.6, [M – 2*sugar + H]⁺ = 1233.6, [M – 3*sugar + H]⁺ = 1030.3, [M + 2H]²⁺ = 820.6. Preparation of AGN306:

130 30124-WO-PCT

[ A- PEG4-Alkyne (201 mg, 122 μmol, 1.20 equivalents) in DMF (2 mL) and water (2 mL) was added a fresh solution of CuSO₄ (0.4 M, 255 μL, 1.00 equivalent), sodium L-ascorbate (0.4 M, 1.02 mL, 4.00 equivalents) and THPTA (44.4 mg, 102 μmol, 1.00 equivalent) at 0°C. The mixture was stirred at 0°C for one hour under nitrogen gas atmosphere. The residue was purified by prep-high performance liquid chromatography (ACOH condition) directly to afford AGN306 (144 mg, 26.6 μmol, 26.08% yield, 96.91% purity) as a white solid. LCMS: retention time = 1.639 minutes, MS calculated: M_av = 5258.92, [M + 3H]³⁺ = 1754.2, [M + 4H]⁴⁺ = 1315.9, [M + 5H]⁵⁺ = 1052.7. EXAMPLE 11 Maleimide-beta-GN3(TBT506) Procedure for Preparation of Target-A001A. See EXAMPLE 9 above. Preparation of Intermediate-2: of 1a (60.0 g, 400 mmol, 2.00 equivalents) in 2-Methyltetrahydrofuran (450 mL) was added 1 (34.2 g, 200 mmol, 1.00 equivalent) in 2-methyltetrahydrofuran (160 mL) at 0°C. The mixture was stirred at 25°C for two hours. TLC (DCM: MeOH = 20: 1, R_f = 0.70) showed the reaction was completed, one major new spot with lower polarity was detected. The reaction mixture was added HCl/EA (1 N, 27.0 mL) and stirred for thirty minutes, and the white precipitate was removed by filtration, the filtrate was concentrated under reduced pressure to afford Intermediate-2 (crude, 105.0 g, 370.6

131 30124-WO-PCT mmol) as yellow oil. LCMS: retention time = 0.797 minutes, MS cal.: 283.14, mass observed: [M + Na]⁺ = 306.1.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.23-7.41 (m, 5 H), 5.01 (s, 2 H), 4.60 (br s, 1 H), 3.45-3.52 (m, 6 H), 3.38-3.43 (m, 5 H), 3.14 (q, J = 5.94 Hz, 2 H), 2.53-2.55 (m, 1 H). of Intermediate-3: added TMSOTf (85.6 g, 385 mmol, 1.50 equivalents) and stirred at 60°C for 2 h. The reaction was then cooled to room temperature (25°C) and stirred for another one hour. A mixture of Intermediate-2 (80.0 g, 282 mmol, 1.10 equivalents) and 4 Å powder molecular sieves (50.0 g) in DCE (500 mL) was added to the reaction. The resulting mixture was stirred for thirty minutes under nitrogen gas atmosphere. Then a solution of Intermediate-2a (100.0 g, 257 mmol, 1.00 equivalent) in DCE was added dropwise to the mixture at 0°C. The mixture was stirred for sixteen hours at 25°C under nitrogen gas atmosphere. Thin- layer chromatography (DCM: MeOH = 10: 1, R_f = 0.42) indicated Intermediate-2a was consumed completely, and one major new spot with larger polarity was detected. The reaction mixture was filtered and washed with sat. NaHCO₃ (500 mL), water (500 mL) and brine (500 mL). The organic layer was dried over anhydrous Na₂SO₄, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, PE: EA = 3: 1 to 1: 6, then DCM: MeOH = 20: 1) to afford Intermediate-3 (90.0 g, 146.9 mmol, 91.6% purity, 57.2% yield) as yellow oil. LCMS: retention time = 0.860 minutes, MS cal.: 612.25, mass observed: [M + H]⁺ = 613.2.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.80 (d, J = 9.03 Hz, 1 H), 7.24-7.39 (m, 6 H), 5.22 (d, J = 3.51 Hz, 1 H), 4.95-5.05 (m, 3 H), 4.53-4.59 (m, 1 H), 3.99-4.06 (m, 3 H), 3.84-3.92 (m, 1 H), 3.73-3.82 (m, 1 H), 3.55-3.61 (m, 1 H), 3.45-3.53 (m, 7 H), 3.41 (t, J = 5.90 Hz, 2 H), 3.11-3.18 (m, 3 H), 2.10 (s, 3 H), 1.99 (s, 3 H), 1.89 (s, 3 H), 1.77 (s, 3 H). Preparation of Intermediate-4:

132 30124-WO-PCT [00435] Pd/C (9.00 g, 10% purity) in reaction bottle (purged with Ar for three times) was added THF (180 mL) slowly, then a solution of trifluoroacetic acid (16.7 g, 147 mmol, 1.00 equivalent) and Intermediate-3 (90.0 g, 147.0 mmol, 1.00 equivalent) in THF (720 mL) was added to the reaction slowly under nitrogen gas. The reaction was degassed and purged with nitrogen gas and hydrogen gas for three times, then stirred at 25°C for three hours under H₂ atmosphere (40 psi). TLC (DCM:methanol = 10: 1, R_f = 0.20) indicated Intermediate-3 was consumed completely, and one major new spot with larger polarity was detected. The reaction mixture was dissolved in THF (100 mL), filtered carefully through siliceous earth under nitrogen gas atmosphere, the cake was washed with THF (100 mL * 2), and the filtrate was concentrated under reduced pressure to get the residue. The residue was diluted with water (1000 mL), washed with DCM (300 mL * 3), the aqueous layer was lyophilized to afford Intermediate-4 (80.0 g, 139.0 mmol, 95.1% purity, 91.8% yield, trifluoroacetic acid salt) as a white solid. LCMS: retention time = 0.484 minutes, MS cal.: 478.22, mass observed: [M + H]⁺ = 478.9.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.91 (br t, J = 9.03 Hz, 4 H), 5.21 (d, J = 3.26 Hz, 1 H), 4.96 (dd, J = 11.17, 3.39 Hz, 1 H), 4.54 (d, J = 8.53 Hz, 1 H), 3.98-4.08 (m, 3 H), 3.85-3.93 (m, 1 H), 3.75-3.84 (m, 1 H), 3.59 (br t, J = 5.14 Hz, 3 H), 3.50- 3.56 (m, 6 H), 2.98 (br s, 2 H), 2.10 (s, 3 H), 2.00 (s, 3 H), 1.89 (s, 3 H), 1.78 (s, 3 H). Preparation of Intermediate-6: in DMSO (166 mL) was added aqueous NaOH (5.0 M, 9.91 mL, 0.10 equivalents) dropwise at 0-15°C for over five minutes . After addition, the mixture was stirred at 0-15°C for five minutes, then 5a (254.0 g, 1.98 mol, 287 mL, 4.00 equivalents) was added to the reaction mixture dropwise at 20°C. The resulting mixture was stirred at 25°C for sixteen hours. TLC (DCM: MeOH = 10: 1, R_f = 0.7) indicated Intermediate-5 was consumed completely, and one major new spot with lower polarity was detected. The resulting reaction mixture was concentrated under reduced pressure to give a residue. The residue was dissolved in ethyl acetate (400 mL), quenched by addition of water (400 mL), and extracted with ethyl acetate (400 mL * 3). The combined organic layers were washed with brine (300 mL * 2), dried over Na₂SO₄, filtered and concentrated under reduced pressure to afford Intermediate-6 (100.0 g, 197.8 mmol, 96.0% purity,

133 30124-WO-PCT 40.0% yield) as colorless oil.¹H NMR (400 MHz, DMSO-d₆) δ ppm 3.51-3.61 (m, 7 H), 3.17 (s, 5 H), 2.39 (t, J = 6.02 Hz, 6 H), 1.40 (s, 27 H). Preparation of Intermediate-7: [00437] To a solution of Intermediate-6 (40.0 g, 79.1 mmol, 1.00 equivalent) in MeCN (400 mL) was added HOBt (10.7 g, 79.1 mmol, 1.00 equivalent). Then 6a (16.5 g, 79.1 mmol, 1.00 equivalent) and DCC (16.3 g, 79.1 mmol, 1.00 equivalent) were added. The reaction was stirred at 25°C for sixteen hours. TLC (PE: EA = 1: 1, R_f = 0.80) indicated Intermediate-6 was consumed completely, and one major new spot with lower polarity was detected. MeCN was evaporated to get the residue. The residue was purified by column chromatography (SiO₂, PE: EA = 10: 1 to 1: 1) to afford Intermediate-7 (40.0 g, 57.4 mmol, 82.9% purity, 72.5% yield) as a white solid. LCMS: retention time = 1.151 minutes, MS cal.: 696.38, mass observed: [M + H]⁺ = 697.3, [M + Na]⁺ = 719.3.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.26-7.40 (m, 6 H), 7.06 (s, 1 H), 5.03 (s, 2 H), 3.49-3.61 (m, 14 H), 2.39 (br t, J = 6.02 Hz, 6 H), 1.40 (s, 27 H). Preparation of Intermediate 8: (300 mL) was stirred at 25°C for sixteen hours. TLC (PE: EA = 1: 1, R_f = 0.04) indicated Intermediate-7 was consumed completely, and one major new spot with larger polarity was detected. Solvent was evaporated under reduced pressure, then co-evaporated with toluene (50 mL * 3) under reduced pressure and dried under reduced pressure to get the residue. The residue was purified by prep-high performance liquid chromatography (A: 0.1% FA condition/water, B: MeCN) to afford Intermediate-8 (20.0 g, 37.8 mmol,

134 30124-WO-PCT 98.2% purity, 87.9% yield).¹H NMR (400 MHz, DMSO-d₆) δ ppm 12.17 (br s, 3 H), 7.26-7.43 (m, 6 H), 7.06 (s, 1 H), 5.02 (s, 2 H), 3.49-3.65 (m, 14 H), 2.42 (br t, J = 6.27 Hz, 6 H). LCMS: retention time = 0.790 minutes, MS cal.: 528.20, mass observed: [M + H]⁺ = 529.2. Preparation of Intermediate-9: [00439] To a stirring solution of Intermediate-8 (20.0 g, 37.8 mmol, 1.00 equivalent) and Intermediate-4 (78.5 g, 132 mmol, 3.50 equivalents, trifluoroacetic acid salt) in DMF (400 mL) was added HOBT (20.4 g, 151 mmol, 4.00 equivalents), EDCI (29.0 g, 151 mmol, 4.00 equivalents) and DIEA (22.0 g, 170 mmol, 4.50 equivalents) successively. The reaction was stirred at 25°C for 2 h. TLC (DCM: MeOH = 10: 1, R_f = 0.4) indicated Intermediate-8 was consumed completely, and one major new spot with larger polarity was detected. The reaction mixture was slowly poured into a stirring cold 0.5 mol/L HCl solution (900 mL) and stirred for ten minutes. White precipitate was formed and filtered. The aqueous phase was extracted with DCM (600 mL* 2) twice. The combined organic layers were washed with 5% NaHCO₃ (450 mL), dried over Na₂SO₄, and concentrated under reduced pressure to get a residue. The residue was purified by column chromatography (SiO₂, DCM: MeOH = 100: 1 to 5: 1) to afford Intermediate-9 (58.0 g, 30.4 mmol, 82.7% purity, 80.3% yield) as a white solid.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.92 (br t, J = 5.14 Hz, 3 H), 7.81 (d, J = 9.03 Hz, 3 H), 7.28-7.39 (m, 6 H), 7.13 (s, 1 H), 5.21 (d, J = 3.26 Hz, 3 H), 5.02 (s, 2 H), 4.97 (dd, J = 11.17, 3.39 Hz, 3 H), 4.54 (d, J = 8.53 Hz, 3 H), 4.03 (s, 9 H), 3.84-3.92 (m, 3 H), 3.75-3.81 (m, 3 H), 3.45-3.61 (m, 37 H), 3.39 (br s, 3 H), 3.18-3.23 (m, 6 H), 2.30 (br t, J=6.15 Hz, 6 H), 2.10 (s, 9 H), 2.00 (s, 9 H), 1.89 (s, 9 H), 1.77 (s, 9 H). LCMS: retention time = 3.455 minutes, MS cal.: 1908.81, mass observed: [M + 2H]²⁺ = 955.7.

135 30124-WO-PCT Preparation of Intermediate 10: [00440] The 500 mL round-bottom flask was purged with Ar gas for 3 times and added dry Pd/C (1.50 g, 1.41 mmol, 10% purity, 1.00 equivalent) carefully. Then THF (150.0 mL) was added to infiltrate the Pd/C completely, followed by the solution of Intermediate-9 (15.0 g, 7.85 mmol, 1.00 equivalent) and trifluoroacetic acid (895 mg, 7.85 mmol, 583 μL, 1.00 equivalent) in THF (75 mL) slowly under Ar atmosphere. The resulting mixture was degassed and purged with H2 for 3 times, and then the mixture was stirred at 25°C for three hours under H₂ atmosphere (15 psi). The reaction was monitored by LCMS, LCMS showed the desired mass (one main peak with desired was detected.). The reaction mixture was filtered carefully through siliceous earth under nitrogen gas atmosphere, the cake was washed with THF (100 mL*2). Then, the filter cake was added water immediately. The organic layer concentrated under reduced pressure to afford Intermediate-10 (13.0 g, 6.54 mmol, 83.2% yield, 99.7% purity, trifluoroacetic acid salt) as a white solid.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.89-7.99 (m, 5 H), 7.82 (d, J = 9.3 Hz, 3 H), 7.74 (s, 1 H), 7.14-7.28 (m, 1 H), 5.22 (d, J = 3.3 Hz, 3 H), 4.97 (dd, J = 11.3, 3.4 Hz, 3 H), 4.54 (d, J = 8.5 Hz, 3 H), 3.84-3.93 (m, 3 H), 3.76-3.82 (m, 3 H), 3.47-3.61 (m, 43 H), 3.21 (q, J = 5.8 Hz, 6 H), 2.29-2.34 (m, 6 H), 2.10 (s, 9 H), 2.00 (s, 9 H), 1.89 (s, 8 H), 1.77 (s, 9 H). LCMS: retention time = 1.333 minutes, MS cal.: 1774.7, found: [M + 2H]²⁺ = 888.6. Preparation of Target-A001A:

136 30124-WO-PCT [00441] To a solution of Intermediate-10 (12.0 g, 6.35 mmol, 1.00 equivalent, trifluoroacetic acid) in MeOH (120.0 mL) was added NaOMe (5.4 M, 5.01 mL, 4.26 equivalents) at 0°C. The mixture was stirred at 0°C for 0.5 h. The reaction was monitored by LCMS, LCMS showed the desired mass (one main peak with desired was detected.). The reaction mixture was added with 1.0 M HCl solution (10.0 mL) till the pH = 6. The mixture was diluted with water (75.0 mL) and extracted with DCM (120 mL * 3). The mixture was freeze-dried to afford Target-A001A (9.0 g, 5.96 mmol, 93.9% yield, >95% purity, HCl) as a white solid.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.96 (br t, J = 5.4 Hz, 3 H), 7.67 (d, J = 8.9 Hz, 3 H), 7.51 (s, 1 H), 4.27 (d, J = 8.4 Hz, 3 H), 3.75-3.80 (m, 6 H), 3.70 (br d, J = 10.0 Hz, 6 H), 3.49 (br d, J = 4.0 Hz, 31 H), 3.37-3.42 (m, 12 H), 3.30 (br d, J = 6.1 Hz, 4 H), 3.20 (br d, J = 5.8 Hz, 6 H), 2.99 (s, 2 H), 2.30 (br t, J = 6.4 Hz, 6 H), 1.80 (s, 9 H). LCMS: retention time = 0.966 minutes, MS cal.: 1396.6, found: [M + 2H]²⁺ = 699.1. Procedure for Preparation of TBT506: [00442] To a solution of Target-A001A (500 mg, 357 μmol, 1.00 equivalent) and 3- maleimidopropionic acid N-hydroxysuccinimide ester (142.869 mg, 536 μmol, 1.50 equivalents) in DMF (5 mL) was added DIEA (46.2 mg, 357 μmol, 59.1 μL, 1.00 equivalent) degassed and purged with nitrogen gas for three times. The mixture was stirred at 0°C for five minutes under nitrogen gas atmosphere. LCMS showed the desired mass (one main peak with desired was detected.). The reaction mixture was purified by prep-high performance liquid chromatography (AcOH condition) directly to

137 30124-WO-PCT afford TBT506 (251.2 mg, 156 μmol, 43.7% yield, 96.5% purity) as a colorless solid. LCMS: retention time = 1.382 minutes, MS cal.: M_av = 1548.59, [M + H]⁺ = 1548.9, [M + 2H]²⁺ = 775.1. EXAMPLE 12 Preparation of TBT644 - A Procedure for Preparation of Intermediate-27: Preparation of Intermediate 2: (40 mL) slowly, then a solution of trifluoroacetic acid (7.44g, 65.2 mmol, 4.86 mL, one equivalent) and Intermediate-1 (40.0 g, 65.2 mmol, 1.00 equivalent) in THF (360 mL) was added to the reaction slowly under nitrogen gas. The reaction was degassed and purged with argon gas and hydrogen gas for three times, then stirred at 25°C for under hydrogen gas atmosphere (40 psi). TLC (DCM: MeOH = 10: 1, R_f = 0.20) indicated Intermediate-1 was consumed completely, and one major new spot with larger polarity was detected. The reaction mixture was dissolved in THF (100 mL), filtered carefully through siliceous earth under nitrogen gas atmosphere, the cake was washed with THF (100 mL * 2), and the filtrate was concentrated under reduced pressure to get Intermediate-2 (38.7 g, 38.5 mmol, 59.0% yield, 59.0% purity, trifluoroacetic acid salt) as a white solid. LCMS: retention time = 0.428 minutes, MS cal.: 478.22, mass observed: [M + Na]⁺ = 501.2.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.79-7.91 (m, 3 H), 5.16-5.28 (m, 1 H), 4.97 (br dd, J = 11.07, 2.81 Hz, 1 H), 4.54 (br d, J = 8.50 Hz, 1 H), 4.03 (s, 2 H), 3.77-3.93 (m, 2 H), 3.53-3.62 (m, 8 H), 2.98 (br d, J = 5.00 Hz, 2 H), 2.10 (s, 3 H), 2.00 (s, 3 H), 1.89 (s, 3 H), 1.78 (s, 3 H).

138 30124-WO-PCT Preparation of Intermediate-4: Intermediate-2 (38.1 g, 64.3 mmol, 4.00 equivalents, trifluoroacetic acid salt) in DMF (17 mL) and DCM (340 mL) was added HOBT (8.69 g, 64.3 mmol, 4.00 equivalents), EDCI (12.3 g, 64.3 mmol, 4.00 equivalents) and DIEA (9.35 g, 72.3 mmol, 4.50 equivalents) successively. The reaction was stirred at 25°C for two hours. TLC (DCM:methanol = 10: 1, R_f = 0.5) indicated Intermediate 3 was consumed completely, and one major new spot with larger polarity was detected. The reaction mixture was slowly poured into a stirring cold 1.0 mol/L HCl solution (350 mL) and stirred for ten minutes. White precipitate was formed and filtered. The aqueous phase was extracted with DCM (350 mL* 2) twice. The combined organic layers were washed with saturated NaHCO₃ (350 mL), dried over Na₂SO₄, and concentrated under reduced pressure to get a residue. The residue was purified by column chromatography (SiO₂, DCM: MeOH = 100: 1 to 15: 1) to afford Intermediate 4 (22.0 g, 10.6 mmol, 66.0% yield, 92.2% purity) as a white solid.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.91 (br t, J = 5.32 Hz, 3 H), 7.81 (d, J = 9.26 Hz, 3 H), 7.26-7.49 (m, 6 H), 7.12 (s, 1 H), 5.21 (d, J = 3.25 Hz, 3 H), 5.02 (s, 2 H), 4.97 (dd, J = 11.13, 3.25 Hz, 3 H), 4.55 (d, J = 8.38 Hz, 3 H), 4.03 (s, 9 H), 3.84-3.92 (m, 3 H), 3.74-3.82 (m, 3 H), 3.47-3.65 (m, 38 H), 3.39 (br s, 3 H), 3.20 (q, J = 5.42 Hz, 6 H), 2.30 (br t, J = 6.13 Hz, 6 H), 2.10 (s, 9 H), 1.99 (s, 9 H), 1.89 (s, 9 H), 1.77 (s, 9 H). LCMS: retention time = 0.403 minutes, MS cal.: 1908.81, mass observed: [M + 2H]²⁺ = 1910.2.

139 30124-WO-PCT Preparation of Intermediate 5: [00445] The 500 mL round-bottom flask was purged with argon gas for three times and added dry Pd/C (1.60 g, 1.50 mmol, 10% purity, 0.17 equivalents) carefully. Then THF (60.0 mL) was added to infiltrate the Pd/C completely, followed by the solution of Intermediate-4 (16.4 g, 8.59 mmol, 1.00 equivalent) and trifluoroacetic acid (979 mg, 8.59 mmol, 637.8 μL, 1.00 equivalent) in THF (100 mL) slowly under argon gas atmosphere. The resulting mixture was degassed and purged with H2 for 3 times, and then the mixture was stirred at 25°C for under H₂ atmosphere (15 psi). TLC (DCM: MeOH = 10: 1, Rf = 0.6) indicated Intermediate 9 was consumed completely, and one major new spot was detected. The reaction mixture was filtered carefully through siliceous earth under nitrogen gas atmosphere, the cake was washed with THF (50 mL*2). Then, the filter cake was added water immediately. The organic layer concentrated under reduced pressure to afford Intermediate-5 (15.7 g, 6.78 mmol, 78.9% yield, 81.6% purity, trifluoroacetic acid salt) as a white solid.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.91-7.98 (m, 5 H), 7.82 (br d, J = 9.13 Hz, 3 H), 7.74 (s, 1 H), 7.12-7.28 (m, 1 H), 5.22 (br d, J = 2.63 Hz, 3 H), 4.97 (br dd, J = 11.13, 2.75 Hz, 3 H), 4.54 (d, J = 8.51 Hz, 3 H), 3.84-3.93 (m, 3 H), 3.78 (br dd, J = 10.13, 4.88 Hz, 3 H), 3.53-3.62 (m, 22 H), 3.33-3.45 (m, 22 H), 3.18-3.25 (m, 6 H), 2.31 (br t, J = 6.13 Hz, 6 H), 2.10 (s, 9 H), 2.00 (s, 9 H), 1.89 (s, 9 H), 1.73-1.81 (m, 14 H). LCMS: retention time = 0.341 minutes, MS cal.: 1774.7, found: [M + 2H]²⁺ = 1776.9.

140 30124-WO-PCT Preparation of Intermediate Target-A001A: MeOH (50.0 mL) was added NaOMe (707 mg, 13.1 mmol, 4.50 equivalents) at 0°C. The mixture was stirred at 0°C for 0.5 hour. The reaction was monitored by LCMS, LCMS showed the desired mass (one main peak with desired was detected.). The reaction mixture was added with 1.0 M HCl solution till the pH = 6. The mixture was diluted with water (75.0 mL) and extracted with DCM (120 mL * 3). The mixture was freeze-dried to afford Target-A001A (4.1 g, 2.74 mmol, 94.1% yield, 93.4% purity, HCl) as a white solid.¹H NMR (400 MHz, DMSO-d₆) δ ppm 7.94 (br t, J = 5.50 Hz, 3 H), 7.62 (d, J = 9.01 Hz, 3 H), 7.54 (s, 1 H), 4.28 (d, J = 8.50 Hz, 3 H), 3.70-3.88 (m, 6 H), 3.61-3.70 (m, 6 H), 3.49-3.57 (m, 31 H), 3.38-3.43 (m, 12 H), 3.31 (br d, J = 6.25 Hz, 4 H), 3.17 (s, 6 H), 3.09 (s, 2 H), 2.30 (br t, J = 6.32 Hz, 6 H), 1.80 (s, 9 H). LCMS: retention time = 0.22 minutes, MS cal.: 1396.6, found: [M + H]⁺ = 1397.8. Preparation of Intermediate Intermediate-27: CH2CO2-NHS (567 mg, 1.71 mmol, 1.20 equivalents) in DMF (20 mL) was added DIEA (554 mg, 4.29 mmol, 709 μL, 3.00 equivalents) at 0°C. The mixture was stirred at 0°C for two hours under nitrogen gas atmosphere. LCMS indicated Target-A001A was consumed completely, one main peak with desired MS was detected. The residue was purified by prep-high performance liquid chromatography (AcOH condition) directly to afford Intermediate-27 (1.75 g, 1.04 mmol, 73.2% yield, 96.5% purity) as a white

141 30124-WO-PCT solid. LCMS: retention time = 0.286 minutes, MS cal.: M_av = 1612.68, [M + 2H]²⁺ = 807.1, [M - sugar + 2H]²⁺ = 705.6. EXAMPLE 13 Procedure for Preparation of TBT644- B Preparation of Intermediate-37: Peptide was synthesized using standard Fmoc chemistry (C resin). [00448] Resin preparation: DMF (100 mL) was added to the vessel containing Rink MBHA-Amide Resin (5.00 mmol, 16.7 g, 0.30 mmol/g) with nitrogen gas bubbling for thirty minutes. The resin was washed with DMF (100 mL * 5), followed by adding 20% piperidine in DMF (50 mL) and bubbled with nitrogen gas for thirty minutes at 25°C for Fmoc deprotection. The mixture was filtered. The resin was washed with DMF (100 mL * 5) before proceeding to next step. [00449] Coupling: A solution of Fmoc-Pra-OH (3.00 equivalents), HATU (2.85 equivalents) in DMF (50 mL) was added to the resin with nitrogen gas bubbling. Then DIEA (6.00 equivalents) was added to the mixture dropwise and bubbled with nitrogen gas for thirty minutes at 25°C. The coupling reaction was monitored by ninhydrin test, if it showed colorless, the coupling was completed. The resin was then washed with DMF (100 mL) * 5. [00450] Deprotection: 20% piperidine in DMF (50 mL) was added to the resin and the mixture was bubbled with nitrogen gas for thirty minutes at 25°C. The resin was then washed with DMF (100 mL) * 5. The de-protection reaction was monitored by ninhydrin test, if it showed blue or brownish red, the reaction was completed. [00451] Steps 2 and 3 were repeated for the following amino acids elongation: Number # 2-3, TABLE 16 below. After the last position completed, the resin was then washed with DMF (100 mL) * 5, MeOH (100 mL) * 5, and dried under reduced pressure to afford peptide-bound-resin (5 mmol).

142 30124-WO-PCT TABLE 16 The list of amino acids and the corresponding reagents used on SPPS. # Materials Coupling reagents 1 Fmoc-Pra-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 2 Fmoc-Gly-Gly-Gly-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) 3 Fmoc-Gly-Gly-OH (3.00 equivalents) HATU (2.85 equiv.) and DIEA (6.00 equiv.) Peptide TFA de-protection: [00452] Trifluoroacetic acid deprotection: peptide-bound-resin was stirred in a solution of TFA/3- MPA/Tis/water (92.5/2.5/2.5/2.5, v/v/v/v, 200 mL) at 25°C for two hours. The mixture was precipitated with isopropyl ether (cold, 2 L). After filtration, the solid was washed with isopropyl ether (cold, 2 L) for two additional times, and dried under reduced pressure for two hours to afford Intermediate-37 (620 mg, crude) as a white solid. The crude was purified by prep-high performance liquid chromatography (A: 0.075% trifluoroacetic acid/water, B: MeCN) directly to afford Intermediate-37 (1.59 g, 3.77 mmol, 75.5% yield, 94.3% purity) as a white solid. LCMS: retention time = 0.071 minutes, MS calculated: M_av = 397.39, mass observed: [M + H]⁺ = 398.1. Preparation of TBT644: 27 (1.69 g, 1.04 mmol, 1.00 equivalent) in DMF (10 mL) was added a solution of CuSO₄ (0.4 M, 2.62 mL, 1.00 equivalent), sodium L-ascorbate (0.4 M, 10.4 mL, 4.00 equivalents) at 0°C. The mixture was stirred at 0°C for two hours under nitrogen gas atmosphere. LCMS indicated Intermediate-27 was consumed completely, one main peak with desired MS was detected. The residue was purified by prep-high performance liquid chromatography (AcOH condition) directly to afford TBT644 (1.377 g, 666 μmol, 63.5% yield, 97.3% purity) as a white solid. LCMS: retention time = 1.372 minutes, MS cal.: Mav = 2010.06, [M + 2H]²⁺ = 1005.7, [M + 3H]³⁺ = 671.0, [M - sugar + 2H]²⁺ = 904.2, [M - 2sugar + 2H]²⁺ = 802.6.

143 30124-WO-PCT EXAMPLE 14 Production protocol for ABT817 Transient expression: [00454] Seed and passage CHO K1 host cells in advance. [00455] On the day of transfection, centrifuge host cells to specific cell density for transfection. [00456] Add DNA and transfection reagent (PEI) into host cell for transfection. [00457] Incubate the transfected culture by shaking at 150 rpm. [00458] Shift temperature from 36.5°C to 33°C for twenty-four hours post transfection. [00459] Perform feeding on day 0 and day 4, while harvest cell culture on day 7 or when VIA<60%. Harvest and clarification: [00460] Subject the cell culture fluid to centrifugation at 10000 g for thirty minutes and then pass through a 0.22 µm sterile filter. Affinity capture by Ni-Excel resin for ABT817 (His tagged recombinant protein) [00461] Purify at 4°C. [00462] Choose the column based on titer, recommended load density (~10 mg/ml resin). [00463] Equilibrate, 10 column volume, with the buffer of 50 mM NaPO4, pH8.0, 200 mM sodium chloride, 10 mM Imidazole. [00464] Sample Load. [00465] EQ wash. Wash with the buffer of 50 mM NaPO4, pH8.0, 200 mM sodium chloride, 10 mM Imidazole, for 2-5 column volume. [00466] Triton wash. Wash with the buffer of 50 mM NaPO4, pH8.0, 200 mM sodium chloride, 10 mM Imidazole, 0.1% TX114, for thirty minutes. [00467] EQ wash. Wash with the buffer of 50 mM NaPO4, pH8.0, 200 mM sodium chloride, 10 mM Imidazole, for ten column volume. [00468] Elute with elution buffer 50 mM PB, 200 mM sodium chloride, 400 mM Imidazole, pH 8.0, for five column volume. [00469] Testing for AC eluates: SDS-PAGE gel non-reducing and reducing, size exclusion chromatography-high performance liquid chromatography. Size Exclusive Chromatography for ABT817 [00470] Purify at room temperature. [00471] Choose the column based on protein amount and molecule weight. (Superdex 200 pg) [00472] Equilibrate with a buffer of phosphate-buffered saline, pH7.4 for one column volume.

144 30124-WO-PCT [00473] Sample load. [00474] Elution with a buffer of phosphate-buffered saline, pH7.4 for one column volume. [00475] Collect target protein with desirable purity. Testing for size exclusion chromatography eluates: SDS-PAGE gel non-reducing and reducing, size exclusion chromatography-high performance liquid chromatography. Cation Exchange Chromatography ABT817 [00476] Purify at room temperature. Use POROS XS column. Choose the column based on protein amount, recommended load density (10-20 mg/ml resin). [00477] Dilute the sample below 5 mS/cm with 50 mM Hepes, pH7.2. [00478] Equilibrate, 5 column volume, with the buffer of 50 mM Hepes, pH7.2. [00479] Sample Load. [00480] EQ wash. Wash with the buffer of 50 mM Hepes, pH7.2. [00481] Elute with Gradient 0-100% 50 column volume, 50 mM Hepes, 1 M sodium chloride, pH7.2 (The scale-up gradient can be adjusted based on the pilot run). [00482] Strip with 50 mM Hepes, 1 M sodium chloride, pH7.2 for 1-3 column volume. [00483] Equilibrate, one column volume, with the buffer of 50 mM Hepes, pH7.2. [00484] Sanitize with 0.5M sodium hydroxide for thirty minutes. [00485] Equilibrate, 3-5 column volume, with the buffer of 50 mM Hepes, pH7.2. [00486] Testing for CEX eluates: SDS-PAGE gel non-reducing and reducing, size exclusion chromatography-high performance liquid chromatography. Size exclusion chromatography-high performance liquid chromatography [00487] Perform size exclusion chromatography-high performance liquid chromatography analysis on a Vanquish Flex Duo liquid chromatography instrument using a TSKgel G3000SWxl stainless steel column (7.8 x 300 mm, particle size 5µm). [00488] The mobile phase consists of 50 mM sodium phosphate and 300 mM sodium chloride at pH 6.8. [00489] Inject 25 µg of sample per run. Perform isocratic elution for fifteen minutes at a flow rate of 1.0 mL/min. Monitor protein elution by ultraviolet absorbance at 280 nm. Integrate the peaks corresponding to aggregates, monomers and LMW species, and calculate the percentage of each species.

145 30124-WO-PCT SDS-PAGE [00490] Perform non-reducing and reducing SDS-PAGE analysis using precast NuPAGE™ 4-12% Bis- Tris Gel from Thermo Scientific. Sample loading buffer (4X LDS) is from Invitrogen. Gel running buffer (20X MES) is from GenScript. [00491] Treat non-reducing samples with 30 mM iodoacetamide and heat at 95°C for five minutes before analysis. Treat reducing samples with 50 mM DTT and heat at 95°C for five minutes before analysis. Carry out electrophoresis at a constant voltage of 180 V for forty minutes. Stain gels using Coomassie blue for thirty minutes and destain with water for one hour. Endotoxin Level Testing [00492] Dilute purified proteins based on maximum valid dilution (MVD) in LAL reagent water (Charles River/W110). [00493] Load samples into Charles River Laboratories EndoSafe LAL Cartridges (Charles River/ PTS11F) and detect them using Charles River Laboratories Endosafe Nexgen-MCS™ instrument. Molecular mass analysis by LC-MS [00494] Conduct LC-MS analysis by using Agilent 6230 AdvanceBio LC/time of flight system with a PL1912-1502, PLRP-S 1000Å, 2.1 x 50 mm, 5 µm column (Agilent/ PL1912-1502). [00495] For the non-reduced intact mass analysis, dilute 200 pmol sample by ddH2O, and subject to LC/MS. For the reduced mass analysis, denature and reduce 100 pmol sample using 10mM Urea (Sigma/15568), 30 mM Tris-HCl (Invitrogen/15568), and DTT (Sigma/D0632) in a total volume of 50 µL. Incubate samples at 37℃ for twenty minutes and then subjected them to LC/MS. [00496] Analyze the mass spectroscopy data using Bioconfirm 10.0 software. Identify molecules based on molecular masses. EXAMPLE 15 Production protocol for ABT818 Transient expression: [00497] Seed and passage CHO K1 host cells in advance. [00498] On the day of transfection, centrifuge host cells to specific cell density for transfection. [00499] Add DNA and transfection reagent (PEI) into host cell for transfection. [00500] Incubate the transfected culture by shaking at 150 rpm. [00501] Shift temperature from 36.5°C to 33°C for twenty-four hours post transfection. [00502] Perform feeding on day 0 and day 4, while harvest cell culture on day 7 or when VIA<60%.

146 30124-WO-PCT Harvest and clarification: [00503] Subject the cell culture fluid to centrifugation at 10000 g for thirty minutes and then pass through a 0.22 µm sterile filter. Anion exchange chromatography ABT818 [00504] Purify at room temperature. [00505] Use POROS 50HQ column. [00506] Choose the column based on protein amount, recommended load density (10-20 mg/ml resin). [00507] Dilute the sample below 5 mS/cm with 20 mM Tris-HCl, pH 7.5. [00508] Equilibrate, 5 column volume, with the buffer of 20 mM Tris-HCl, pH 7.5. [00509] Sample Load. [00510] EQ wash. Wash with the buffer of 20 mM Tris-HCl, pH 7.5. [00511] Elute with Gradient 0-100% 50 column volume 20 mM Tris-HCl, 1 M sodium chloride, pH 7.5 (The scale-up gradient can be adjusted based on the pilot run). [00512] Strip with 20 mM Tris-HCl, 1 M sodium chloride, pH 7.5 for 1-3 column volume. [00513] Equilibrate, one column volume, with the buffer of 20 mM Tris-HCl, pH 7.5. [00514] Sanitize with 0.5 M sodium hydroxide for thirty minutes. [00515] Equilibrate, 3-5 column volume, with the buffer of 20 mM Tris-HCl, pH 7.5. [00516] Testing for CEX eluates: SDS-PAGE gel NR and R, size exclusion chromatography-high performance liquid chromatography. Size exclusive chromatography for ABT818 [00517] Purify at room temperature. Choose the column based on protein amount and molecule weight. (Superdex 200 pg) [00518] Equilibrate with a buffer of phosphate-buffered saline, pH7.4 for one column volume. [00519] Sample load. [00520] Elution with a buffer of phosphate-buffered saline, pH7.4 for one column volume. [00521] Collect target protein with desirable purity. Testing for size exclusion chromatography eluates: SDS-PAGE gel non-reducing and reducing, size exclusion chromatography-high performance liquid chromatography.

147 30124-WO-PCT Size exclusion chromatography-high performance liquid chromatography [00522] Perform size exclusion chromatography-high performance liquid chromatography analysis on a Vanquish Flex Duo liquid chromatography instrument using a TSKgel G3000SWxl stainless steel column (7.8 x 300 mm, particle size 5 µm). [00523] The mobile phase consists of 50 mM sodium phosphate and 300 mM sodium chloride at pH 6.8. [00524] Inject 25 µg of sample per run. Perform isocratic elution for fifteen minutes at a flow rate of 1.0 mL/min. Monitor protein elution by ultraviolet absorbance at 280 nm. Integrate the peaks corresponding to aggregates, monomers and low molecular weight species, and calculate the percentage of each species. SDS-PAGE [00525] Perform non-reducing and reducing SDS-PAGE analysis using precast NuPAGE™ 4-12% Bis- Tris Gel from Thermo Scientific. Sample loading buffer (4X LDS) is from Invitrogen. Gel running buffer (20X MES) is from GenScript. [00526] Treat non-reducing samples with 30 mM iodoacetamide and heat at 95°C for five minutes before analysis. Treat reducing samples with 50 mM DTT and heat at 95°C for five minutes before analysis. Carry out electrophoresis at a constant voltage of 180 V for forty minutes. Stain gels using Coomassie blue for thirty minutes and destain with water for one hour. Endotoxin level testing [00527] Dilute purified proteins based on maximum valid dilution (MVD) in LAL reagent water (Charles River/W110). [00528] Load samples into Charles River Laboratories EndoSafe LAL Cartridges (Charles River/ PTS11F) and detect them using Charles River Laboratories Endosafe Nexgen-MCS™ instrument. Molecular mass analysis by LC-MS [00529] Conduct LC-MS analysis by using Agilent 6230 AdvanceBio LC/ time of flight system with a PL1912-1502, PLRP-S 1000Å, 2.1 x 50 mm, 5 µm column (Agilent/ PL1912-1502). [00530] For the nonreduced intact mass analysis, dilute 200 pmol sample by ddH2O, and subject to LC/MS. For the reduced mass analysis, denature and reduce 100 pmol sample using 10 mM Urea (Sigma/15568), 30 mM Tris-HCl (Invitrogen/15568), and DTT (Sigma/D0632) in a total volume of 50 µL. Incubate samples at 37℃ for 20 min and then subjected them to LC/MS. [00531] Analyze the mass spec data using Bioconfirm 10.0 software and identify molecules based on molecular masses.

148 30124-WO-PCT EXAMPLE 16 Production protocol ABT819 Transient expression: [00532] Seed and passage CHO K1 host cells in advance. [00533] On the day of transfection, centrifuge host cells to specific cell density for transfection. [00534] Add DNA and transfection reagent (PEI) into host cell for transfection. [00535] Incubate the transfected culture by shaking at 150 rpm. [00536] Shift temperature from 36.5°C to 33°C for twenty-four hours post transfection. [00537] Perform feeding on day 0 and day 4, while harvest cell culture on day 7 or when VIA<60%. Harvest and clarification: [00538] Subject the cell culture fluid to centrifugation at 10000 g for thirty minutes and then pass through a 0.22 µm sterile filter. Affinity capture by Ni-Excel Resin for ABT819 (His tagged recombinant protein) [00539] Purify at 4°C. [00540] Choose the column based on titer, recommended load density (5-10 mg/ml resin). [00541] Equilibrate, 10 column volume, with the buffer of 50 mM NaPO4, pH 8.0, 200 mM sodium chloride, 10 mM Imidazole. [00542] Sample Load. [00543] EQ wash. Wash with the buffer of 50 mM NaPO4, pH8.0, 200 mM sodium chloride, 10 mM Imidazole, for 2-5 column volume. [00544] Triton wash. Wash with the buffer of 50 mM NaPO4, pH8.0, 200 mM sodium chloride,10 mM Imidazole, 0.1% TX114, for thirty minutes. [00545] EQ wash. Wash with the buffer of 50 mM NaPO4, pH8.0, 200 mM sodium chloride, 10 mM Imidazole, for 10 column volume. [00546] Elute with elution buffer 50 mM PB, 200 mM sodium chloride, 400 mM Imidazole, pH 8.0, for five column volumes. [00547] Testing for AC eluates: SDS-PAGE gel non-reducing and reducing, size exclusion chromatography-high performance liquid chromatography. Size exclusive chromatography ABT819 [00548] Purify at 4°C. Choose the column based on protein amount and molecule weight. (Superdex 200 pg)

149 30124-WO-PCT [00549] Equilibrate with a buffer of phosphate-buffered saline, pH7.4 for one column volume. [00550] Sample load. [00551] Elution with a buffer of phosphate-buffered saline, pH7.4 for one column volume. [00552] Collect target protein with desirable purity. [00553] Testing for size exclusion chromatography eluates: SDS-PAGE gel non-reducing and reducing, size exclusion chromatography-high performance liquid chromatography. Anion exchange chromatography for ABT819 [00554] Purify at room temperature. Use POROS 50HQ column. [00555] Choose the column based on protein amount, recommended load density (10-20 mg/ml resin). [00556] Dilute the sample below 5 mS/cm with 20 mM Tris-HCl, pH 7.5. [00557] Equilibrate, 5 column volume, with the buffer of 20 mM Tris-HCl, pH 7.5. [00558] Sample Load. [00559] EQ wash. Wash with the buffer of 20 mM Tris-HCl, pH 7.5. [00560] Elute with Gradient 0-100% 50 column volume 20 mM Tris-HCl, 1 M sodium chloride, pH 7.5 The scale-up gradient can be adjusted based on the pilot run. [00561] Strip with 20 mM Tris-HCl, 1 M sodium chloride, pH 7.5 for 1-3 column volume. [00562] Equilibrate, one column volume, with the buffer of 20 mM Tris-HCl, pH 7.5. [00563] Sanitize with 0.5M sodium hydroxide for thirty minutes. [00564] Equilibrate, 3-5 column volume, with the buffer of 20 mM Tris-HCl, pH 7.5. [00565] Testing for CEX eluates: SDS-PAGE gel nonreducing and reducing, size exclusion chromatography-high performance liquid chromatography. Size exclusion chromatography-high performance liquid chromatography [00566] Perform size exclusion chromatography-high performance liquid chromatography analysis on a Vanquish Flex Duo liquid chromatography instrument using a TSKgel G3000SWxl stainless steel column (7.8 x 300 mm, particle size 5µm). [00567] The mobile phase consists of 50 mM sodium phosphate and 300 mM sodium chloride at pH 6.8. [00568] Inject 25 µg of sample per run. Perform isocratic elution for fifteen minutes at a flow rate of 1.0 mL/min. Monitor protein elution by ultraviolet absorbance at 280 nm. Integrate the peaks corresponding to aggregates, monomers and LMW species, and calculate the percentage of each species.

150 30124-WO-PCT SDS-PAGE [00569] Perform Non-reducing and reducing SDS-PAGE analysis using precast NuPAGE™ 4-12% Bis- Tris Gel from Thermo Scientific. Sample loading buffer (4X LDS) is from Invitrogen. Gel running buffer (20X MES) is from GenScript. [00570] Treat non-reducing samples with 30 mM iodoacetamide and heat at 95°C for five minutes before analysis. Treat reducing samples with 50 mM DTT and heat at 95°C for five minutes before analysis. Carry out electrophoresis at a constant voltage of 180 V for forty minutes. Stain gels using Coomassie blue for thirty minutes and destain with water for one hour. Endotoxin level testing [00571] Dilute purified proteins based on maximum valid dilution (MVD) in LAL reagent water (Charles River/W110). [00572] Load samples into Charles River Laboratories EndoSafe LAL Cartridges (Charles River/ PTS11F) and detect them using Charles River Laboratories Endosafe Nexgen-MCS™ instrument. Molecular mass analysis by LC-MS [00573] Conduct LC-MS analysis by using Agilent 6230 AdvanceBio LC/time of flight system with a PL1912-1502, PLRP-S 1000Å, 2.1 x 50 mm, 5 µm column (Agilent/ PL1912-1502). [00574] For the nonreduced intact mass analysis, dilute 200 pmol sample by ddH2O, and subject to LC/MS. For the reduced mass analysis, denature and reduce 100 pmol sample using 10mM Urea (Sigma/15568), 30mM Tris-HCl (Invitrogen/15568), and DTT (Sigma/D0632) in a total volume of 50 µL. Incubate samples at 37℃ for 20 min and then subjected them to LC/MS. [00575] Analyze the mass spec data using Bioconfirm 10.0 software and identify molecules based on molecular masses. EXAMPLE 17 Production protocol for ABT740 Transient expression: [00576] Seed and passage CHO K1 host cells in advance. [00577] On the day of transfection, centrifuge host cells to specific cell density for transfection. [00578] Add DNA and transfection reagent (PEI) into host cell for transfection. [00579] Incubate the transfected culture by shaking at 150 rpm. [00580] Shift temperature from 36.5°C to 33°C for twenty-four hours post-transfection. [00581] Perform feeding on day 0 and day 4, while harvest cell culture on day 7 or when VIA<60%.

151 30124-WO-PCT Harvest and clarification: [00582] Subject the cell culture fluid to centrifugation at 10000 g for thirty minutes and then pass through a 0.22 µm sterile filter. Affinity capture by Ni-Excel Resin for ABT740 (His tagged recombinant protein) [00583] Purify at 4°C. Choose the column based on titer, recommended load density (~10 mg/ml resin). [00584] Equilibrate, ten column volumes, with the buffer of 50 mM NaPO4, pH8.0, 200 mM sodium chloride, 10 mM Imidazole. [00585] Sample Load. [00586] EQ wash. Wash with the buffer of 50 mM NaPO4, pH8.0, 200 mM sodium chloride, 10 mM Imidazole, for 2-5 column volume. [00587] Triton wash. Wash with the buffer of 50 mM NaPO4, pH8.0, 200 mM sodium chloride, 10 mM Imidazole, 0.1% TX114, for thirty minutes. [00588] EQ wash. Wash with the buffer of 50 mM NaPO4, pH8.0, 200 mM sodium chloride, 10 mM Imidazole, for 10 column volume. [00589] Elute with elution buffer 50 mM PB, 200 mM sodium chloride, 400 mM Imidazole, pH 8.0, for 5 column volume. [00590] Testing for AC eluates: SDS-PAGE gel non-reducing and reducing, size exclusion chromatography-high performance liquid chromatography. Anion Exchange Chromatography for ABT740 [00591] Purify at room temperature. Use Q-HP column. [00592] Choose the column based on protein amount, recommended load density (10-20 mg/ml resin). [00593] Dilute the sample below 5 mS/cm with 20 mM Tris-HCl, pH 7.5. [00594] Equilibrate, five column volumes, with the buffer of 20 mM Tris-HCl, pH 7.5. [00595] Sample Load. [00596] EQ wash. Wash with the buffer of 20 mM Tris-HCl, pH 7.5. [00597] Elute with Gradient 0-100% 50 column volume, 20 mM Tris-HCl, 1 M sodium chloride, pH 7.5 (The scale-up gradient can be adjusted based on the pilot run). [00598] Strip with 20 mM Tris-HCl, 1 M sodium chloride, pH 7.5 for 1-3 column volume. [00599] Equilibrate, one column volume, with the buffer of 20 mM Tris-HCl, pH 7.5. [00600] Sanitize with 0.5M sodium hydroxide for thirty minutes.

152 30124-WO-PCT [00601] Equilibrate, 3-5 column volume, with the buffer of 20 mM Tris-HCl, pH 7.5. [00602] Testing for CEX eluates: SDS-PAGE gel non-reducing and reducing, size exclusion chromatography-high performance liquid chromatography. Size exclusion chromatography-high performance liquid chromatography [00603] Perform size exclusion chromatography-high performance liquid chromatography analysis on a Vanquish Flex Duo liquid chromatography instrument using a TSKgel G3000SWxl stainless steel column (7.8 x 300 mm, particle size 5 µm). [00604] The mobile phase consists of 50 mM sodium phosphate and 300 mM sodium chloride at pH 6.8. [00605] Inject 25 µg of sample per run. Perform isocratic elution for fifteen minutes at a flow rate of 1.0 mL/min. Monitor protein elution by ultraviolet absorbance at 280 nm. Integrate the peaks corresponding to aggregates, monomers and low molecular weight species, and calculate the percentage of each species. SDS-PAGE [00606] Perform non-reducing and reducing SDS-PAGE analysis using precast NuPAGE™ 4-12% Bis- Tris Gel from Thermo Scientific. Sample loading buffer (4X LDS) is from Invitrogen. Gel running buffer (20X MES) is from GenScript. [00607] Treat non-reducing samples with 30 mM iodoacetamide and heat at 95°C for five minutes before analysis. Treat reducing samples with 50 mM DTT and heat at 95°C for five minutes before analysis. Carry out electrophoresis at a constant voltage of 180 V for forty minutes. Stain gels using Coomassie blue for thirty minutes and destain with water for one hour. Endotoxin level testing [00608] Dilute purified proteins based on maximum valid dilution (MVD) in LAL reagent water (Charles River/W110). [00609] Load samples into Charles River Laboratories EndoSafe LAL Cartridges (Charles River/ PTS11F) and detect them using Charles River Laboratories Endosafe Nexgen-MCS™ instrument. Molecular mass analysis by LC-MS [00610] Conduct LC-MS analysis by using Agilent 6230 AdvanceBio LC/time of flight system with a PL1912-1502, PLRP-S 1000Å, 2.1 x 50 mm, 5 µm column (Agilent/ PL1912-1502). [00611] For the non-reduced intact mass analysis, dilute 200 pmol sample by ddH2O, and subject to LC/MS. For the reduced mass analysis, denature and reduce 100 pmol sample using 10 mM Urea

153 30124-WO-PCT (Sigma/15568), 30 mM Tris-HCl (Invitrogen/15568), and DTT (Sigma/D0632) in a total volume of 50 µL. Incubate samples at 37℃ for 20 min and then subjected them to LC/MS. [00612] Analyze the mass spec data using Bioconfirm 10.0 software and identify molecules based on molecular masses. EXAMPLE 18 Technical Report for AGN167 (ABT740-TBT506, target BAR = 1) [00613] The of AGN167 molecule is a cysteine-based antibody-conjugate. The molecule consists of one single chain (ABT740, His-tagged protein). The maleimide-containing payload (TBT506) is conjugated to C-terminal cysteine of ABT740 via Michael-addition reaction. The targeting BAR is 1 Expected outcome: [00614] BAR: 0.9-1.1. [00615] Purity by size exclusion chromatography (high performance liquid chromatography): >95%. [00616] Free drug residue: <5% (mol/mol of total drug). [00617] Endotoxin: <0.5 EU/mg. Methods [00618] Purification method for antibody-conjugate by Zeba Spin desalting column. [00619] The Zeba Spin desalting column (40K, 10mL) was preprocessed according to the following procedure: [00620] (1) Removed the column’s bottom closure and centrifuged (700 g, 2 min) to remove the storage solution. [00621] (2) Added 5 mL of phosphate-buffered saline, pH 7.4 onto the resin, centrifuged (700 g, 2 min) and discarded flow-through. Repeated this step two additional times until the pH of the flow through was same as formulation buffer. The centrifuge time for the last balance was five minutes . [00622] (3) Transferred the columns to new collection tubes and applied the conjugation mixture on top of the resin. [00623] (4) Centrifuged (700 g, four minutes) and collected flow-through that contained product. [00624] Purification method for antibody-conjugate by Amicon^® Ultra Centrifugal Filter Unit. An ultrafiltration membrane having a molecular weight of 10 kDa is preferable to concentrate the sample. The Amicon Ultra Centrifugal Filter Unit was used according to the following procedure: [00625] (1) dH2O wash the centrifugal filter unit. [00626] (2) Equilibrated the centrifugal filter unit with phosphate-buffered saline, pH 7.4.

154 30124-WO-PCT [00627] (3) Add up sample to the Amicon^® Ultra filter device and centrifuged to concentrate. [00628] (4) Collected and filtered sample with 0.22 µm membrane. [00629] Ultraviolet–visible spectroscopy platform by Nanodrop to determine monoclonal antibody concentration. [00630] (1) The ultraviolet absorption at 280 nm were measured respectively. [00631] (2) Calculation method based on Beer-Lambert Law A=E*C*l. [00632] A₂₈₀=E^mAb 2₈₀*C_[mAb]*l. [00633] E: weight extinction coefficient. [00634] C: weight concentration (mg/mL). [00635] l: light path (Nanodrop: 0.1 cm). [00636] (3) C_[mAb](mg/mL) = A280 /( E^mAb 2₈₀*l). [00637] BAR determination by LC-MS. LC-MS was performed using a combination of Agilent 1260 series high performance liquid chromatography system and time-of-flight mass spectrometry. BAR was calculated based on the peak abundance of the deconvoluted Mass. [00638] (1) Preparation of sample used in LC-MS analysis (reduction of antibody-drug conjugate). The preparation of LC-MS analysis samples includes denaturation, deglycosylation and reduction. [00639] (a) Denaturation. Transfer 20 μg of sample into 1.5 mL tube, add conjugation buffer to final 10 μL (2 mg/mL), then incubate this solution at 75^oC for five minutes . [00640] (b) Deglycosylation. Transfer 15 µg of denatured samples (7.5 μL) into a 1.5 mL tube, add 3 µL Rapid PNGase F (non-reducing format, 5X) enzyme buffer and 1 µL Rapid PNGase F (non-reducing format) enzyme for de-glycosylation and 3.5 µL water to ensuring the total volume is 15 µL, then incubate this solution at 50^oC for fifteen minutes . [00641] can Reduction.1 μL of 0.1M DTT, 3 μL Tris, pH 8.0 was added to 11 μL deglycosylated sample. The mixture was incubated at 37°C for fifteen minutes to prepare a sample in which the disulfides between the heavy chain and the light chain and between the heavy chain and the heavy chain of the antibody-drug conjugate were cleaved. The obtained sample was used in an LC-MS analysis. LC-MS/MS method. A high performance liquid chromatography analysis was carried out under the following measurement conditions.

155 30124-WO-PCT TABLE 17 LC parameters for BAR determination Equipment HPLC Agilent 1260 Column: Agilent PLRP-S, 50 x 2.1 mm, 8 μm, 1000Å Detection Wavelength: 280 nm, 214nm Column Oven Temp.: 80°C Sampler Temp.: 2~8℃ Flow Rate: 0.5 mL/min Injection Amount: 2 μg Mobile Phases: A:0.025% TFA + 0.1% FA in water B:0.025% TFA + 0.1% FA in CAN Gradient Program Ten minutes Gradient Time (min) B (%) 0.0 25 0.7 34 5 45 6 90 7 90 7.1 25 10.0 25 TABLE 18 TOF parameters for BAR determination Equipment Agilent 6224TOF Polarity positive Gas Temp. 350oC Drying Gas 13 L/min Nebulizer 45 psig Vcap 5000 V Fragmentor 250 V Mass Range 500 – 8000 m/z Acquisition Rate 1 spectra/s

156 30124-WO-PCT [00642] Aggregation determination by size exclusion chromatography-high performance liquid chromatography. Size-exclusion chromatography was performed using an Agilent 1260 series high performance liquid chromatography system with the TSK gel G3000SWXL Size-exclusion chromatography column (7.8×300 mm, 5 µm) at 25°C. The mobile phase was consisted of 78 mM KH₂PO₄, 122 mM K₂HPO₄, 250 mM potassium chloride, 15% isopropanol at pH 7.0±0.1. The flow rate was set at 0.75 mL/min. Sample loading was 40~50 μg per injection. Samples were detected at 280 nm and 220 nm with an ultraviolet detector. The retention time of the aggregation peak was recorded based on its relative molecular weight. And the aggregation level was determined by the relative area of the peak at 280 nm. [00643] Hydrophobicity determination by hydrophobic interaction chromatography-high performance liquid chromatography. Hydrophobic Interaction Chromatography was performed using an Agilent 1260 series high performance liquid chromatography system with the TSK gel butyl-nonporous Hydrophobic Interaction chromatography column (4.6×35 mm, 5 µm) at 25°C. The mobile phase A was consisted of 1.5 M (NH₄)₂SO₄ and 50 mM K₂HPO_4·3H₂O, at pH 7.2±0.2, Cond.190,000±200 us/cm. The mobile phase B was consisted of 50 mM Potassium Phosphate and 25% 2-propanol, at pH 7.4±0.2, Cond. 3400±200 us/cm. The flow rate was set at 0.6 mL/min. Sample loading was 8 μL per injection. Samples were detected at 280 nm with an ultraviolet detector. TABLE 19 hydrophobic interaction chromatography-high performance liquid chromatography parameters Column TOSOH, TSKgel Butyl-NPR, 2.5 μm, 4.6 * 35 mm Detection 280 nm BW 4 Column Oven Temp.: 25°C Sampler Temp.: 6 ± 2°C Flow Rate: 0.6 mL/min Stop Time: Twenty minutes Maximum Pressure: 300 bar Injection Amount: 8 µL Mobile Phases: Mobile Phase A: 1.5 M (NH₄)₂SO₄ and 50 mM K₂HPO₄·3H₂O Mobile Phase B: 50 mM potassium phosphate and 25% 2-propanol

157 30124-WO-PCT TABLE 19 hydrophobic interaction chromatography-high performance liquid chromatography parameters Column TOSOH, TSKgel Butyl-NPR, 2.5 μm, 4.6 * 35 mm Gradient Program: Time (min) A (%) B (%) 0 100 0 2 100 0 15 0 100 16 0 100 17 100 0 20 100 0 [00644] Residual free drug determination by Reverse phase-ultra performance liquid chromatography. The residual free drug level was determined by reverse phase ultra-performance liquid chromatography. After protein precipitation, supernatant was loaded to Luna Omega 1.6 μm Polar C18 100Å column, then eluted by a gradient of increasing the organic mobile phase. The percentage of residual free drug was quantified via peak area by comparing it to external standard curve. Solvent preparation: [00645] Solvent I (for protein precipitation). Weighed 10 g sodium chloride to the pre-mixed organic solvent of 30 mL methanol and 50 mL CAN, mixed and stirred one hour at least, allowed the solution to stand for at least one hour before use. The supernatant was the saturated sodium chloride solution. [00646] Solvent II (diluent). Added 3 mL dimethyl sulfoxide to 27 mL formulation buffer and mixed well. Then added 60 mL solvent I and mixed well again. [00647] Preparation of standard curve. The stock standard linker-drug solution was diluted with dimethyl sulfoxide to 1 mM. Added 20 mL of the 1 mM linker-payload solution to 180 mL Solvent II to a final concentration of 100 μM. Then serially diluted the 100 μM standard solution. [00648] TABLE 20 Linker-payload standard curve preparation Standard Volume of Volume of Total Volume Final Concentration Concentration (µM) Stock (µL) Diluent (µL) (µL) (µM) 100 150 150 300 50 50 200 300 500 20 20 200 200 400 10

158 30124-WO-PCT TABLE 20 Linker-payload standard curve preparation Standard Volume of Volume of Total Volume Final Concentration Concentration (µM) Stock (µL) Diluent (µL) (µL) (µM) 10 200 200 400 5 5 200 300 500 2 2 200 200 400 1 1 200 200 400 0.5 [00649] Preparation of samples. Added 3 µL of dimethyl sulfoxide to 27 µL of antibody-conjugate sample and mixed well. Then added 60 μL solvent I and vortex the mixture for ten minutes on a mixer at room temperature. Centrifuged the mixture for ten minutes at 16,000 rcf at room temperature. And then pipetted 100 µL of the supernatant immediately into a glass high performance liquid chromatography vial for analysis. TABLE 21 Reverse phase-ultra performance liquid chromatography method for free drug test Column: Luna Omega 1.6 μm Polar C18100Å Detection Wavelength: 220nm Column Oven Temp.: 30°C Sampler Temp.: 2~8℃ Flow Rate: 0.4 mL/min Injection Volume: 40 μL Mobile Phases: A: 0.1% trifluoroacetic acid in water B: 0.1% trifluoroacetic acid in CAN Gradient Program Forty minutes Gradient Time (min) B (%) 0.00 2.00 32.00 50.00 32.01 90.00 35.00 90.00 37.01 2.00 40.00 2.00 [00650] Data analysis: Integrated the stand BAR curve injections. Plotted the peak area (Y) as a function of concentration (X), Y=Kx + b. Calculated the slope (k) and intercept (b).

159 30124-WO-PCT [00651] Integrated the related drug peak in the sample. Recorded the sum peak area (Y) and interpolated against the standard curve. Calculated the concentration obtained. _{[00652] Cfreedrug^ = ,!"#} $ _{- × dilute^factor} [00653] C_{free drug} = of free drug by C18-ultra performance liquid chromatography [00654] Y = sum peak of drug related impurities [00655] k = slope of standard curve [00656] b = intercept of standard curve [00657] Report the relative amount of residual free drug in antibody-conjugate product (%mol/mol) with two decimal place. !"#$$^&#'( _{[00658] %mol/mol = ^} )*&#'( !"#$$^&#'( ₊ !,#-.$/0 _{∗ 100} _{)*&#'( )*,#-} ultra performance liquid chromatography [00660] C _protein= concentration of protein (mg/mL) [00661] BAR = drug to antibody ratio by LC-MS [00662] Mw _{Linker payload} = molecular weight of drug [00663] Mw _protein = molecular weight of monoclonal antibody [00664] The endotoxin level was determined by kinetic turbidimetric assay. [00665] Preparation of Endotoxin Standards and quality control: The CSE (10EU/vial, lyophilized) is reconstituted with 1 mL of water for BET to yield a 10 EU/mL standard solution. Make 10-fold dilution using the water for BET, prepare standard solutions with four concentrations (S1_10 EU/mL, S2_1 EU/mL, S3_0.1 EU/mL, S4_0.01 EU/mL). Dilute CSE with Water for BET to prepare quality control (0.05 EU/mL). [00666] Preparation of TAL Reagents: The TAL reagent is stable when stored at 2~8℃ before expiration. Allow reagents to equilibrate to room temperature prior to use. Added 1.25 mL Water for BET to dissolve one bottle of TAL reagent. [00667] Preparation of Samples: diluted all the sample X/2 folds with Water for BET. Taken half volume of X/2 folds sample and added equal volume of Water for BET to make the finally tested sample with X folds dilution. Added equal volume of S3 in the remaining half of volume of X/2 folds sample to make its PPC sample with endotoxin concentration to quality control.

160 30124-WO-PCT [00668] Add 100 μL of the standard curve, quality control, sample, PPC and NTC into wells. Add 100 μL of TAL reagent into the 96-well plat wells(Greiner-655185). All standards control and samples need duplicate. Read microplate with a plate reader. [00669] OD 405 nm was read during incubating at 37^oC for 100 min in a microplate reader. [00670] A standard curve was prepared by plotting the average 405nm measurement for each standard vs. its endotoxin level in EU/mL. [00671] Standard curve was used to determine the endotoxin level of samples. Conjugation methods [00672] Conjugation buffer and formulation buffer. AGN167, reduction/conjugation buffer: phosphate-buffered saline, pH 7.4, formulation buffer: phosphate-buffered saline, pH 7.4. [00673] Procedure of bulk conjugation [00674] Reduction: To the 5 mL tube (MACRO TUBE 5) containing 12 mg of ABT740 in original buffer (7.13 mg/mL in phosphate-buffered saline, pH 7.4), 5 mM tris(2-carboxyethyl)phosphine solution (1.5 equivalents), 200 mM diethylenetriamine-pentaacetic acid solution and phosphate-buffered saline, pH 7.4 reduction/conjugation buffer were added. The protein concentration in the reaction was 6.00 mg/mL. The diethylenetriamine-pentaacetic acid concentration in the reaction was 4 mM. The reactions were mixed well and incubated at 22^oC for one hour. [00675] Conjugation: Added TBT506 (10 mM in dimethyl sulfoxide) (3 equivalents) into the reactions, mixed well and incubated at 22^oC for another one hour. The crude conjugation was then purified by Zeba Spin desalting column (40K, 10mL) and collected flow-through that contained product. [00676] The flow-through was then buffer exchanged and concentrated via Amicon® Ultra Centrifugal Filter Unit (10K, 15mL) with phosphate-buffered saline, pH 7.4 (Gibco, 10010031) for 30 DV. [00677] The purified sample was filtered with 0.22 µm filter. [00678] Perform the quality control test (including concentration, size exclusion chromatography- high performance liquid chromatography, hydrophobic interaction chromatography -high performance liquid chromatography, LC-MS, free drug and endo level). [00679] Results and discussion of AGN167. After conjugation, the reaction mixture is purified by Zeba and buffer exchanged via Amicon® with phosphate-buffered saline, pH 7.4 buffer, then filter with 0.22 μm membrane.

161 30124-WO-PCT TABLE 22 Reaction condition for bulk conjugation # Scale TCEP/Protein Drug/Protein Organic Solvent Reaction Temp. (mg) ratio ratio & Time AGN167 ABT740- 12 1.5 3 4.4% DMSO Reduction: 22^oC, TBT506 one hour, Conj.: 22^oC, one hour TABLE 23 Molecular information of AGN167 # BAR1 Molecular weight Modification Theoretical Measured Difference (Da) (Amino acid, Da) Mass (Da) Mass (Da) AGN167 42918.22 BAR1 42934.36 42935.10 0.74 TABLE 24 Quality control summary of AGN167 # Purity % LC-MS Percentage of Amount Yield Conc. Endo Free BAR target BAR % (mg) (%) (mg/mL) (EU/mg) drug (LCMS) (%) AGN167 95.48 0.91 84.37 8.13 67.75 7.27 <0.206 <1.03 [00680] Freeze/thaw stability tests. Store the sample under -70°C for one hour to ensure that material is frozen, then the material is allowed to thaw by letting the vial to sit at room temperature for sufficient amount of time until completed thawed. Collect the analytical characterization under different freeze-thaw cycles (1, 2, 3). TABLE 25 Results for Freeze/thaw tests Sample ID Name SEC purity% Conc.(mg/mL) BAR Percentage of target BAR % AGN167 Before F/T 95.48 7.27 0.91 84.37 1st F/T 95.01 7.29 0.89 83.65 2nd F/T 95.05 6.90 0.90 83.50 3rd F/T 95.08 7.02 0.89 83.27 [00681] Summary. The AGN167 product was successfully generated. All the results meet targeting quality. Samples are stable under three freeze-thaw cycles.

162 30124-WO-PCT TABLE 26 Equipment name Equipment information HPLC Agilent Technologies, HPLC 1260 UHPLC Agilent Technologies/Agilent 1290 LC-MS Agilent Technologies, HPLC 1260 / 6224 TOF Nanodrop 2000 Thermo Scientific, 1294881 Pure water generator Milli-Q Reference TABLE 27 Material name Material information Column for LC-MS Agilent Technologies, PLRP-S, 1000Å 8 µm 50*2.1 mm, PL1912-1802 SEC column TOSOH, TSKgel G3000SWXL, 7.8×300 mm, 5 μm, 08541 C18 column Agilent Technologies, InfinityLab Poroshell 120 SB-C18, 4.6 x 100 mm, 2.7 µm, 685975-902 HIC column TOSOH, TSKgel Butyl-NPR, 2.5 μm, 4.6 * 35 mm Free drug column Luna Omega 1.6 μm Polar C18100 Å Zeba Spin Desalting Column Thermo Scientific, 40 K MWCO, 10 mL Amicon, 10 kDa 15 mL Millipore-UFC901024 Millex-GP Syringe Filter Unit, 0.22 µm millipore-SLGPR33RB 1X PBS, pH 7.4 Gibco, 10010031 Acetonitrile Merck, Supelco-1.00030.4008 Trifluoroacetic acid jkchemical-134753 Na₂HPO₄.7H₂O Sigma-S2429-500G NaH₂PO₄ Sigma-S5011-500G (NH₄)₂SO₄ Sigma-A4418-1KG 2-propanol Sigma-34863 K₂HPO₄ SIGMA/ P5655 KH2PO4·3H2O SIGMA/ 900170 Methanol Merck, 106007 Sodium Chloride Domestic Tris(2-carboxyethyl)phosphine Sigma-C4706

163 30124-WO-PCT Diethylenetriamine-pentaacetic acid Sigma-17969-500ML Dimethyl sulfoxide Sigma-Aldrich,BCCL4606 Rapid PNGase F (non-reducing format) BioLabs-P0711S 5X Rapid PNGase F buffer (non-reducing BioLabs-B0717S format) L-histidine Merck/1.04352.1000 L-histidine.HCl Avantor-4942-06 Sucrose Pfanstiehl/ S-124-1-MC EXAMPLE 19 AGN364 (ABT817-TBT644, Target BAR = 1) [00682] The molecule of AGN364 is a sortase-ligation based antibody-conjugate. The molecule consists of one single chain (ABT817, peptide), which is conjugated to a pentaglycine modified TBT644 via sortase-catalyzed ligation. The targeting BAR is 1. Characteristics for the antibody-conjugate product are shown: [00683] BAR: 0.9-1.1 [00684] Purity by size exclusion chromatography (HPLC): >95% [00685] Free drug residue: <5% (mol/mol of total drug) [00686] Endotoxin: <0.5 EU/mg. Methods. Purification method for antibody conjugate by Ni Excel. [00687] The solution was purified by Ni Excel to remove sortase A and unconjugated protein. [00688] Instrument: AKTA pure. [00689] Column: HisTrap excel, 5 mL. [00690] Equilibration buffer: 20 mM sodium phosphate, 500 mM sodium chloride, 10 mM imidazole pH 7.4 [00691] Elution buffer: 0.2M sodium hydroxide. [00692] Flow rate: 4 mL/min. [00693] Wavelength: 280 nm. [00694] Purification method by Amicon^® Ultra Centrifugal Filter Unit [00695] An ultrafiltration membrane having a molecular weight of 10 kDa is preferable to concentrate the sample. The Amicon Ultra Centrifugal Filter Unit was used according to the following procedure:

164 30124-WO-PCT [00696] dH₂O wash the centrifugal filter unit. [00697] Equilibrated the centrifugal filter unit with phosphate-buffered saline, pH 7.4. [00698] Add up sample to the Amicon^® Ultra filter device and centrifuged to concentrate. [00699] Collected and filtered sample with 0.22 µm membrane. [00700] Ultraviolet–visible spectroscopy platform by Nanodrop to determine protein concentration of in-process sample and final product. [00701] (1) 750 nm was set up as baseline. [00702] (2) The UV absorption at 280 nm and 220 nm were measured respectively [00703] (3) Calculation method based on Beer-Lambert Law A=E*C*l [00704] A₂₈₀=E^mAb 2₈₀*C_[mAb]*l [00705] E: molar extinction coefficient; [00706] C: molar concentration; [00707] l: light path (Nanodrop: 0.1 cm) [00708] BAR determination by LC-MS. LC-MS was performed using a combination of Agilent 1260 series high performance liquid chromatography system and time-of-flight mass spectrometry. BAR was calculated based on the peak abundance of the deconvoluted mass. [00709] Preparation of sample used in LC-MS analysis. [00710] An antibody-drug conjugate solution was diluted to approximately 1 mg/mL, 30uL totally with water. The obtained sample was used in an LC-MS analysis. [00711] LC-MS/MS method. A high performance liquid chromatography analysis was carried out under the following measurement conditions. TABLE 28 LC parameters for BAR determination Equipment HPLC Agilent 1260 Column: Agilent PLRP-S, 50 x 2.1 mm, 8 μm, 1000Å Detection Wavelength: 280 nm, 214nm Column Oven Temp.: 80°C Sampler Temp.: 2~8℃ Flow Rate: 0.05 mL/min Injection Amount: 2 μg Mobile Phases: A:0.025%TFA+0.1%FA in water B:0.025%TFA+0.1%FA in acetonitrile

165 30124-WO-PCT TABLE 28 LC parameters for BAR determination Gradient Program ten minutes Gradient Time (min) B (%) 0.0 5 0.7 5 5 45 6 90 7 90 7.1 5 10.0 5 TABLE 29 Time of flight parameters for BAR determination Equipment Agilent 6230TOF Polarity positive Gas Temp. 350oC Drying Gas 13 L/min Nebulizer 45 psig VCap 5000 V Fragmentor 350 V Mass Range 500 – 8000 m/z Acquisition Rate 1 spectra/s [00712] Aggregation determination by size exclusion chromatography-high performance liquid chromatography. Size-exclusion chromatography was performed using an Agilent 1260 series high performance liquid chromatography system with the TSK gel G3000SWXL Size-exclusion chromatography column (7.8×300 mm, 5 µm) at 25°C. The mobile phase was consisted of 78 mM KH₂PO₄, 122 mM K₂HPO₄, 250 mM potassium chloride, 15% isopropanol at pH 7.0±0.1. The flow rate was set at 0.75 mL/min. Sample loading was 40~50 μg per injection. Samples were detected at 280 nm and 370 nm with an ultraviolet detector. The retention time of the aggregation peak was recorded based on its relative molecular weight. The aggregation level was determined by the relative area of the peak at 280 nm.

166 30124-WO-PCT [00713] Residual free drug determination by LC-MS. The residual free drug level was determined by LC-MS. After protein precipitation, supernatant was loaded to InfinityLab Poroshell 120 SB-C18, 4.6 x 100 mm, 2.7 µm column, and eluted by a gradient of increasing the organic mobile phase. The percentage of residual free drug was quantified via peak area by comparing it to external standard curve. [00714] Solvent I preparation: Weighed 10 g sodium chloride to the pre-mixed organic solvent of 30 mL methanol and 50 mL acetonitrile, mixed and stirred one hour at least, allowed the solution to stand for at least one hour before use. The supernatant was the saturated sodium chloride solution. [00715] Preparation of standard curve. The stock standard linker-drug solution was firstly diluted to 40 µM with dimethyl sulfoxide for standard curve preparation. Then the standard curve and sample were prepared (MW_mAb 21382 Da, monoclonal antibody concentration 7.87mg/mL and BAR value 1.00 were used for calculation). TABLE 30 Linker-payload Standard Preparation Solution Final V_protein Final Drug Drug V_Drug DMSO V_DMSO V_H2O Solvent ID mAb (µL) Conc. Conc. (µL) Vol. (µL) (µL) I (µL) Conc. (%mol/mol) (µM) frac. (mg/mL) STD 5% 1.00 19.06 5.00 2.46 9.23 0.1 5.77 15.9 100.00 STD 2% 1.00 19.06 2.00 0.95 3.58 0.1 11.42 15.9 100.00 STD 1% 1.00 19.06 1.00 0.47 1.77 0.1 13.23 15.9 100.00 . TABLE 31 Sample Preparation Conc. (mg/mL) V_ADC(µL) DMSO volume frac. V_DMSO(µL) V_H2O(µL) Solvent I(µL) 1.00 13.8 0.1 15.00 21.2 100.00 TABLE 32 LC parameters for free drug determination Column: Agilent PLRP-S, 50 x 2.1 mm, 8 μm, 1000Å Detection Wavelength: 280 nm, 220nm Column Oven Temp.: 80°C Sampler Temp.: 2~8℃ Flow Rate: 0.4 mL/min

167 30124-WO-PCT TABLE 32 LC parameters for free drug determination Stop Time: 13 minutes Maximum Pressure: 350 bar Injection Amount: 20 µL Mobile Phases: Mobile Phase A: 0.025% TFA + 0.1% FA in water Mobile Phase B: 0.025% TFA + 0.1% FA in acetonitrile Gradient Program Time(min) A% B% 2.00 95.0 5.0 5.00 70.0 30.0 8.00 20.0 80.0 8.50 10.0 90.0 10.00 10.0 90.0 10.01 95.0 5.0 13.00 95.0 5.0 TABLE 33 Q-TOF parameters for free drug determination Equipment Agilent 6530 QTOF Polarity positive Gas Temp. 250^oC Drying Gas 13 L/min Nebulizer 45 psig VCap 3500 V Fragmentor 125 V Mass Range 150 – 8000 m/z Acquisition Rate spectra/s Endotoxin determination [00717] The endotoxin level was determined by Endosafe® Nexgen-PTS™. [00718] Diluted sample with endo-free water, pipetted 25 µL of diluted sample into each of the four reservoirs of the PTS Cartridge. The reader drew and mixed the sample with the LAL reagent in the sample channels in addition to the LAL reagent plus positive product control in the spike channels. The

168 30124-WO-PCT sample was combined with the chromogenic substrate then incubated. After mixing, the optical density of the wells was measured and analyzed against an internally archived standard curve. Conjugation methods: [00719] Conjugation and formulation buffer. AGN364, conjugation buffer: 50mM HEPES, 150mM sodium chloride, 10% glycerol(V/V), pH 7.5, formulation buffer, phosphate-buffered saline, 2mM EDTA, pH 7.4. Procedure of bulk conjugation [00720] (1) To 150 mL bottle (Corning, 431175) containing 100 mg of ABT817 in original buffer (50 mM HEPES, 150 mM sodium chloride, 10% glycerol(V/V), pH 7.5) were added with 5.08 mg/mL sortase A (PT-0008, 0.01 equivalents) solution, TBT644 (40 mM in dimethyl sulfoxide) (sixteen equivalents) into the reactions, mixed well and incubated at 4^oC for overnight. The protein concentration in the reaction was 3 mg/mL. [00721] (2) The crude conjugation was purified with AKTA pure chromatography. The conjugate and free linker-payload were flowed through. The sortase A and unconjugated protein with His-tag were bounded to the column and eluted by 0.2M NaOH. Pooled flow through liquid together and performed buffer exchange to phosphate-buffered saline, pH7.4, 5% dimethyl sulfoxide for 30 DV follow by phosphate-buffered saline, pH7.4 for 20 DV with Amicon® Ultra Centrifugal Filter Unit (10 kDa, 4*15mL). Add 200mM EDTA to keep the final formulation buffer contained 2mM EDTA. [00722] (3) The purified sample was filtered with 0.22 µm filter. [00723] (4) Perform the quality control test (including concentration, size exclusion chromatography- high performance liquid chromatography, hydrophobic interaction chromatography-high performance liquid chromatography, LC-MS, free drug and endotoxin level). [00724] Results and discussion of bulk conjugation. After conjugation, the reaction mixture is purified by Ni Excel and exchange buffer to phosphate-buffered saline, pH 7.4 use with Amicon® Ultra Centrifugal Filter Unit (10 kDa, 4*15mL), supplement 2mM EDTA, then filter with 0.22 μm membrane. TABLE 34 Reaction condition for bulk conjugation # Sortase A/ Drug/mAb Conjugation Conjugation Conjugation mAb ratio ratio Conc. (mg/mL) temp.& time pH AGN364 ABT817- 0.01 16 3 4^oC, overnight 7-7.5 TBT644

169 30124-WO-PCT TABLE 35 Molecular information of AGN364 # BAR1 Molecular Modification Theoretical Measured Difference (Da) weight (Amino Mass (Da) Mass (Da) acid, Da) AGN364 19718.04 G3FNS2 22435.5 22436.86 1.36 TABLE 36 Results for bulk conjugation # UV Conc. Amount MS-BAR SEC-Purity Free drug Endo (mg/mL) (mg) (%) (%) (EU/mg) AGN364 10.86 69.40 1.00 99.05 <1.0 <0.092 [00725] Results and discussion of stability tests. Store the sample under -70°C for one hour to ensure that material is frozen, then the material is allowed to thaw by letting the vial to sit at room temperature for sufficient amount of time until completed thawed. Collect the analytical characterization under different freeze-thaw cycles (1, 2, 3). TABLE 37 Results for thermal stability tests. Time point (cycles) Conc.(mg/mL) SEC purity (%) BAR AGN364 1 98.65 10.93 1.00 2 98.65 10.87 1.00 3 98.68 11.02 1.00 [00726] Summary. The AGN364 product was successfully generated. All the results meet targeting quality. Sample was stable under three freeze-thaw cycles. EXAMPLE 20 AGN365 (ABT819-TBT644, target BAR = 1) [00727] The molecule of AGN365 is a sortase-ligation based antibody-conjugate. The molecule consists of one single chain (ABT819, peptide), which is conjugated to a pentaglycine modified TBT644 via sortase-catalyzed ligation.

170 30124-WO-PCT Characteristics for the product are shown: [00728] BAR: 0.9-1.1 [00729] Purity by size exclusion chromatography (HPLC): >95% [00730] Free drug residue: <5% (mol/mol of total drug) [00731] Endotoxin: <0.5 EU/mg. Methods [00732] Purification method by Ni Excel. The solution was purified by Ni Excel to remove sortase A and unconjugated protein. [00733] Instrument: AKTA pure. [00734] Column: HisTrap excel, 5 mL. [00735] Equilibration buffer: 20 mM sodium phosphate, 500 mM sodium chloride, 10 mM imidazole pH 7.4 [00736] Elution buffer: 0.2M NaOH [00737] Flow rate: 4 mL/min. [00738] Wavelength: 280 nm. [00739] Purification method by Amicon^® Ultra Centrifugal Filter Unit [00740] An ultrafiltration membrane having a molecular weight of 10 kDa is preferable to concentrate the sample. The Amicon Ultra Centrifugal Filter Unit was used according to the following procedure: [00741] dH₂O wash the centrifugal filter unit. [00742] Equilibrated the centrifugal filter unit with phosphate-buffered saline, pH 7.4. [00743] Add up sample to the Amicon^® Ultra filter device and centrifuged to concentrate. [00744] Collected and filtered sample with 0.22 µm membrane. [00745] Ultraviolet–visible spectroscopy platform by Nanodrop to determine protein concentration of in-process sample and final product. [00746] (1) 750 nm was set up as baseline. [00747] (2) The ultraviolet absorption at 280 nm and 220 nm were measured respectively. [00748] (3) Calculation method based on Beer-Lambert Law A=E*C*l. [00749] A₂₈₀=E^mAb 2₈₀*C_[mAb]*l. [00750] E: molar extinction coefficient. [00751] C: molar concentration. [00752] l: light path (Nanodrop: 0.1 cm).

171 30124-WO-PCT [00753] BAR determination by LC-MS. [00754] LC-MS was performed using a combination of Agilent 1260 series high performance liquid chromatography system and time-of-flight mass spectrometry. BAR was calculated based on the peak abundance of the deconvoluted Mass. [00755] Preparation of sample used in LC-MS analysis. An antibody-drug conjugate solution was diluted to approximately 1 mg/mL, 30uL totally with water. The obtained sample was used in an LC-MS analysis. [00756] A high performance liquid chromatography analysis was carried out under the following measurement conditions. TABLE 38 LC parameters for BAR determination Equipment HPLC Agilent 1260 Column: Agilent PLRP-S, 50 x 2.1 mm, 8 μm, 1000Å Detection Wavelength: 280 nm, 214nm Column Oven Temp.: 80°C Sampler Temp.: 2~8℃ Flow Rate: 0.05 mL/min Injection Amount: 2 μg Mobile Phases: A:0.025%TFA+0.1%FA in water B:0.025%TFA+0.1%FA in acetonitrile Gradient Program Ten minutes Gradient Time (min) B (%) 0.0 5 0.7 5 5 45 6 90 7 90 7.1 5 10.0 5

172 30124-WO-PCT TABLE 39 Time-of-flight parameters for BAR determination Equipment Agilent 6230TOF Polarity positive Gas Temp. 350^oC Drying Gas 13 L/min Nebulizer 45 psig VCap 5000 V Fragmentor 350 V Mass Range 500 – 8000 m/z Acquisition Rate 1 spectra/s [00757] Aggregation determination by SEC-HPLC. Size-exclusion chromatography was performed using an Agilent 1260 series high performance liquid chromatography system with the TSK gel G3000SWXL Size-exclusion chromatography column (7.8×300 mm, 5 µm) at 25°C. The mobile phase was consisted of 78 mM KH₂PO₄, 122 mM K₂HPO₄, 250 mM potassium chloride, 15% isopropanol at pH 7.0±0.1. The flow rate was set at 0.75 mL/min. Sample loading was 40~50 μg per injection. Samples were detected at 280 nm and 370 nm with an ultraviolet detector. The retention time of the aggregation peak was recorded based on its relative molecular weight. And the aggregation level was determined by the relative area of the peak at 280 nm. [00758] Residual free drug determination by LC-MS: The residual free drug level was determined by LC-MS. After protein precipitation, supernatant was loaded to InfinityLab Poroshell 120 SB-C18, 4.6 x 100 mm, 2.7 µm column, and eluted by a gradient of increasing the organic mobile phase. The percentage of residual free drug was quantified via peak area by comparing it to external standard curve. [00759] Solvent I preparation: Weighed 10g sodium chloride to the pre-mixed organic solvent of 30 mL methanol and 50 mL ACN, mixed and stirred one hour at least, allowed the solution to stand for at least one hour before use. The supernatant was the saturated sodium chloride solution. [00760] Preparation of standard curve. The stock standard linker-drug solution was firstly diluted to 40 µM with dimethyl sulfoxide for standard curve preparation. Then the standard curve and sample were prepared (MW_mAb 43861 Da, monoclonal antibody concentration 7.38 mg/mL and BAR value 0.99 were used for calculation).

173 30124-WO-PCT TABLE 40 Linker-payload Standard Preparation Final mAb V_protein Final Drug Drug V_Drug DMSO V_DMSO V_H2O Solvent Conc. (µL) Conc. Conc. (µL) Volume (µL) (µL) I (µL) (mg/mL) (%mol/mol) (µM) frac. STD 1.00 20.33 5.00 1.19 4.45 0.1 10.55 14.7 100.00 5% STD 1.00 20.33 2.00 0.46 1.73 0.1 13.27 14.7 100.00 2% STD 1.00 20.33 1.00 0.23 0.85 0.1 14.15 14.7 100.00 1% [00761] The sample were prepared (product concentration 10.41 mg/mL.) TABLE 41 Sample preparation Conc. (mg/mL) V_ADC(µL) DMSO volume frac. V_DMSO (µL) V_H2O (µL) Solvent I (µL) 1.00 14.4 0.1 15.00 20.6 100.00 TABLE 42 LC parameters for free drug determination Column: Agilent PLRP-S, 50 x 2.1 mm, 8 μm, 1000Å Detection Wavelength: 280 nm, 220nm Column Oven Temp.: 80°C Sampler Temp.: 2~8℃ Flow Rate: 0.4 mL/min Stop Time: 13 min Maximum Pressure: 350 bar Injection Amount: 20 µL Mobile Phases: Mobile Phase A: 0.025%TFA+0.1%FA in H₂O Mobile Phase B: 0.025%TFA+0.1%FA in ACN

174 30124-WO-PCT TABLE 42 LC parameters for free drug determination Gradient Program Time(min) A% B% 2.00 95.0 5.0 5.00 70.0 30.0 8.00 20.0 80.0 8.50 10.0 90.0 10.00 10.0 90.0 10.01 95.0 5.0 13.00 95.0 5.0 TABLE 43 Q-TOF parameters for free drug determination Equipment Agilent 6530 Q-TOF Polarity positive Gas Temp. 250^oC Drying Gas 13 L/min Nebulizer 45 psig VCap 3500 V Fragmentor 125 V Mass Range 150 – 8000 m/z Acquisition Rate 1 spectra/s [00762] Endotoxin determination. The endotoxin level was determined by Endosafe® Nexgen-PTS™. Diluted sample with endo-free water, pipetted 25 µL of diluted sample into each of the four reservoirs of the PTS Cartridge. The reader drew and mixed the sample with the LAL reagent in the sample channels in addition to the LAL reagent plus positive product control in the spike channels. The sample was combined with the chromogenic substrate then incubated. After mixing, the optical density of the wells was measured and analyzed against an internally archived standard curve.

175 30124-WO-PCT Conjugation methods [00763] Conjugation buffer and formulation buffer: AGN365, conjugation buffer, 50mM HEPES, 150mM sodium chloride, 10% glycerol(V/V), pH 7.5, formulation buffer, phosphate-buffered saline, 2mM EDTA, pH 7.4. Procedure of bulk conjugation [00764] (1) To 150 mL bottle (Corning, 431175) containing 100 mg of ABT819 in original buffer (50mM HEPES, 150 mM sodium chloride, 10% Glycerol(V/V), pH 7.5) were added with 5.08 mg/mL sortase A (PT-0008, 0.01 equivalents) solution, TBT644 (40 mM in DMSO) (sixteen equivalents) into the reactions, mixed well and incubated at 4^oC for overnight. The protein concentration in the reaction was 3 mg/mL. [00765] (2) The crude conjugation was purified with AKTA pure chromatography. The conjugate and free linker-payload were flowed through. The sortase A and unconjugated protein with His-tag were bounded to the column and eluted by 0.2M NaOH. Pooled flow through liquid together and performed buffer exchange to phosphate-buffered saline, pH7.4, 5% DMSO for 30 DV follow by phosphate-buffered saline, pH7.4 for 20 DV with Amicon® Ultra Centrifugal Filter Unit (10 kDa, 4*15mL). Add 200 mM EDTA to keep the final formulation buffer contained 2 mM EDTA. [00766] (3) The purified sample was filtered with 0.22 µm filter. [00767] (4) Perform the quality control test (including concentration, SEC-high performance liquid chromatography, hydrophobic interaction chromatography-high performance liquid chromatography, LC-MS, free drug and endotoxin level). [00768] Results and discussion of bulk conjugation. After conjugation, the reaction mixture is purified by Ni Excel and exchange buffer to phosphate-buffered saline, pH 7.4 use with Amicon® Ultra Centrifugal Filter Unit (10 kDa, 4*15mL), supplement 2 mM EDTA, then filter with 0.22 μm membrane. TABLE 44 Reaction condition for bulk conjugation # Sample ID Sortase Drug/mAb Conjugation Conjugation Conjugation A/mAb ratio ratio Conc. (mg/mL) temp.& time pH AGN365 ABT819- 0.01 16 3 4^oC, 7-7.5 TBT644 overnight

176 30124-WO-PCT TABLE 45 Molecular information of AGN365 BAR1 Molecular weight Modification Theoretical Measured Difference (Amino acid, Da) Mass (Da) Mass (Da) (Da) AGN365 42561.91 G2FS2 44914.12 44914.95 0.83 TABLE 46 Results for bulk conjugation # UV Conc. Amount MS-BAR SEC-Purity Free drug Endo (EU/mg) (mg/mL) (mg) (%) (%) AGN365 10.41 69.12 0.99 98.79 <1.0 <0.048 [00769] Results and discussion of stability tests. Store the sample under -70°C for one hour to ensure that material is frozen, then the material is allowed to thaw by letting the vial to sit at room temperature for sufficient amount of time until completed thawed. Collect the analytical characterization under different freeze-thaw cycles (1, 2, 3). TABLE 47 Results for thermal stability tests # Time point Concentration SEC purity (%) BAR (cycles) (mg/mL) AGN365 1 98.78 10.10 0.99 2 98.78 10.20 0.98 3 98.78 10.09 0.98 [00770] Summary. The AGN365 product was successfully generated. All the results meet targeting quality. Sample was stable under three freeze-thaw cycles. EXAMPLE 21 AGN579 (ABT818-TBT-307, Target BAR = 2) [00771] The molecule of AGN579 is a lysine-based antibody-conjugate. The molecule consists of two same single chains covalently linked by disulfide bonds (ABT818, Fc-fusion). The payload (TBT307) is conjugated to lysine amines in the antibody. The leaving group will be eliminated when the payload is conjugated to amines.

177 30124-WO-PCT Characteristics for the product: [00772] BAR: 1.8-2.2 [00773] Purity by size exclusion chromatography (HPLC): >95% [00774] Free drug residue: <5% (mol/mol of total drug) [00775] Endotoxin: <0.5 EU/mg. [00776] Purification method by UF/DF. An ultrafiltration membrane (Pellicon30.11m² Cassette, Ultracel 30 kDa) having a molecular weight of 30 kDa is preferable to concentrate the sample. The UF/DF was preprocessed according to the following procedure: [00777] (1) Assemble the UF/DF system and install the cassette (0.11 m² membrane area, 30 kDa MWCO). [00778] (2) Flush the system with water, clean with the 0.1 M sodium hydroxide for 30minutes, and flush with water again. [00779] (3) Add phosphate-buffered saline, pH 7.4 to the feed tank. Start the feed pump. Verify that the pH and conductivity in the system have been equilibrated to the level of the phosphate-buffered saline. [00780] (4) Add reaction mixture solution to the feed tank. Start the feed pump by partially closing the retentate valve and adjusting the pump speed. Diafilter the product with the phosphate-buffered saline, pH7.410% DMSO for 40 DV, followed by phosphate-buffered saline, pH7.4 for 20 DV. [00781] (5) Open the retentate valve fully and collect all the product. Filter the product by 0.22μm membrane. [00782] (6) Test the quality and concentration of product. [00783] Ultraviolet–visible spectroscopy platform by Nanodrop to determine protein concentration of in-process sample and final product. [00784] (1) 750 nm was set up as baseline. [00785] (2) The UV absorption at 280 nm and 220 nm were measured respectively. [00786] (3) Calculation method based on Beer-Lambert Law A=E*C*l. [00787] A₂₈₀=E^mAb 2₈₀*C_[mAb]*l [00788] E: molar extinction coefficient; [00789] C: molar concentration; [00790] l: light path (Nanodrop: 0.1 cm)

178 30124-WO-PCT [00791] BAR determination by LC-MS. LC-MS was performed using a combination of Agilent 1260 series high performance liquid chromatography system and time-of-flight mass spectrometry. BAR was calculated based on the peak abundance of the deconvoluted Mass. [00792] Preparation of sample used in LC-MS analysis (Deglycosylation). Transfer 15 µg of samples into a 1.5 mL tube, add 3 µL Rapid PNGase F (non-reducing format, 5X) enzyme buffer and 0.5 µL Rapid PNGase F (non-reducing format) enzyme for de-glycosylation and some water to ensuring the total volume is 15 µL, then incubate this solution at 37 ℃ for two hours or overnight. The obtained sample was used in an LC-MS analysis. [00793] A high performance liquid chromatography analysis was carried out under the following measurement conditions. TABLE 48 Liquid chromatography parameters for BAR determination Equipment HPLC Agilent 1290 Column: Agilent PLRP-S, 50 x 2.1 mm, 8 μm, 1000A Detection Wavelength: 280 nm, 214nm Column Oven Temp.: 30°C Sampler Temp.: 2~8℃ Flow Rate: 0.05 mL/min Injection Amount: 3 μg Mobile Phases: A:0.025%TFA+0.1%FA in water B:0.025%TFA+0.1%FA in ACN Gradient Program ten minutes Gradient Time (min) B (%) 0.0 5 0.3 20 2 30 5 50 7 90 8 90 8.1 5 10.0 5

179 30124-WO-PCT TABLE 49 Q-TOF parameters for BAR determination Equipment Agilent 6530 Q-TOF Polarity positive Gas Temp. 350^oC Drying Gas 13 L/min Nebulizer 45 psig VCap 5000 V Fragmentor 350 V Mass Range 500 – 8000 m/z Acquisition Rate 1 spectra/s [00794] Aggregation determination by SEC-HPLC. Size-exclusion chromatography was performed using an Agilent 1260 series HPLC system with the TSK gel G3000SWXL Size-exclusion chromatography column (7.8×300 mm, 5 µm) at 25°C. The mobile phase was consisted of 78 mM KH₂PO₄, 122 mM K₂HPO₄, 250 mM potassium chloride, 15% isopropanol at pH 7.0±0.1. The flow rate was set at 0.75 mL/min. Sample loading was 40~50 μg per injection. Samples were detected at 280 nm and 370 nm with a UV detector. The retention time of the aggregation peak was recorded based on its relative molecular weight. And the aggregation level was determined by the relative area of the peak at 280 nm. [00795] Residual uABT & LP determination by reverse phase-UPLC. The residual free drug level was determined by reverse phase UPLC. After protein precipitation, supernatant was loaded to Luna Omega 1.6 μm Polar C18100Å column and eluted by a gradient of increasing the organic mobile phase. The percentage of residual free drug was quantified via peak area by comparing it to external standard curve. [00796] Solvent preparation: Solvent I (for protein precipitation) [00797] Weighed 10 g sodium chloride to the pre-mixed organic solvent of 30 mL methanol and 50 mL ACN, mixed and stirred one hour at least, allowed the solution to stand for at least one hour before use. The supernatant was the saturated sodium chloride solution. [00798] Dilution buffer I. Mix 250 µL of DMSO, 700 µL of phosphate-buffered saline, 1000 µL of 6 mg/mL Herceptin® in phosphate-buffered saline as buffer I. [00799] Dilution buffer II. Mix 300 µL of DMSO, 700 µL of phosphate-buffered saline, 1000µL of 6 mg/mL Herceptin® in phosphate-buffered saline as buffer II.

180 30124-WO-PCT [00800] Preparation of standard curve (uABT (cpd1724) /linker payload (TBT307)). The stock standard uABT (cpd1724) /linker payload (TBT307) solution was firstly diluted to 1000 µM with DMSO for standard curve preparation. Add 10 µL of the 1000 μM uABT to 390 µL of dilution buffer I for a final concentration of 25 μM. Then the standard curve and sample were prepared. Take 160 μL of each standard samples and add 240 μl solvent buffer I as final standard curve (10 μM, 5 μM, 2 μM, 1 μM, 0.5 μM, 0.2 μM, 0.1 μM). Vortex solution for ten minutes at room temperature. Centrifuge solution for ten minutes at 16,000 rcf at room temperature. Remove the supernatant immediately into a glass vial for analysis. TABLE 50 uABT/linker Dilution table Standard Conc. Volume of Stock (µL) Volume of dilution Total Final Conc. (μM) buffer II (µL) Volume (µL) (μM) 25 200 200 400 12.5 12.5 160 240 400 5 5 200 200 400 2.5 2.5 200 200 400 1.25 1.25 160 240 400 0.5 0.5 120 120 240 0.25 [00801] Preparation of sample. Mix 30 µL sample with 60 μL solvent I (sample: precipitant 1:2 v/v). Vortex solution for ten minutes at room temperature. Centrifuge solution for ten minutes at 16,000 rcf at room temperature. Remove the supernatant immediately into a glass vial for analysis. TABLE 51 Reverse phase-HPLC parameters for free drug determination Column: Luna Omega 1.6 μm Polar C18100Å Detection Wavelength: 220nm Column Oven Temp.: 30°C Sampler Temp.: 2~8℃ Flow Rate: 0.4 mL/min Injection Volume: 40 μL Mobile Phases: A: 0.1% TFA in water B: 0.1% TFA in ACN Gradient Program forty minutes

181 30124-WO-PCT TABLE 51 Reverse phase-HPLC parameters for free drug determination Gradient Time (min) B (%) 0.00 2.00 32.00 50.00 32.01 90.00 35.00 90.00 37.01 2.00 40.00 2.00 [00802] Data analysis (linker payload) [00803] Integrated the stand BAR curve injections. Plotted the peak area (Y) as a function of concentration (X), Y=Kx + b. Calculated the slope (k) and intercept (b). [00804] Integrated the related drug peak in the sample. Recorded the sum peak area (Y) and interpolated against the standard curve. Calculated the concentration obtained. _{[00805] Clinker^payload^ = ,!"#} $ _{- × dilute^factor} [00806] C_{linker payload} = of linker payload by C18-UPLC [00807] Y = sum peak areas of drug related impurities [00808] k = slope of standard curve [00809] b = intercept of standard curve [00810] Report the relative amount of residual linker payload in product (%mol/mol) with two decimal place. !5/06$#^,7857-& _{[00811] %mol/mol = ^} )*5/06$#^,785-7& 7& !,#- _{∗ 100} C18-UPLC (mg/mL) [00813] C _protein= concentration of protein (mg/mL) [00814] BAR = drug to antibody ratio by LC-MS [00815] Mw _{Linker payload} = molecular weight of drug [00816] Mw _protein = molecular weight of monoclonal antibody [00817] Data analysis (uABT) [00818] Integrated the stand BAR curve injections. Plotted the peak area (Y) as a function of concentration (X), Y=Kx + b. Calculated the slope (k) and intercept (b).

182 30124-WO-PCT [00819] Integrated the related drug peak in the sample. Recorded the sum peak area (Y) and interpolated against the standard curve. Calculated the concentration obtained. _{[00820] CuABT^ = ,!"#} $ _{- × dilute^factor} [00821] of uABT by C18-UPLC [00822] of drug related impurities [00823] k = slope of standard curve [00824] b = intercept of standard curve [00825] Report the relative amount of residual uABT in product (%mol/mol) with two decimal place. !^'329 _{[00826] %mol/mol = ^} )*'329 !,#-.$/0 _{∗ 100} )*,#-.$/0 by C18-UPLC (mg/mL) p_rotein= (mg/mL) [00829] BAR = drug to antibody ratio by LC-MS [00830] Mw _uABT = molecular weight of uABT [00831] Mw _protein = molecular weight of mAb [00832] Residual payload determination by RP-UPLC. The residual free drug level was determined by reverse phase UPLC. After protein precipitation, supernatant was loaded to Luna Omega 1.6 μm Polar C18100Å column and eluted by a gradient of increasing the organic mobile phase. The percentage of residual free drug was quantified via peak area by comparing it to external standard curve. [00833] Solvent preparation: Solvent I (for protein precipitation) [00834] Weighed 10 g sodium chloride to the pre-mixed organic solvent of 30 mL MeOH and 50 mL ACN, mixed and stirred one hour at least, allowed the solution to stand for at least one hour before use. The supernatant was the saturated sodium chloride solution. [00835] Solvent II. Add 5 mL formulation buffer to 10 mL Solvent I (FB: precipitant 1:2 v/v) and mix well. [00836] Preparation of standard curve (payload cpd1777). The stock standard payload cpd1777 solution was firstly diluted to 1000 µM with formulation buffer for standard curve preparation. Add 10 µL of the 1000 μM payload cpd1777 to 90 µL of solvent II for a final concentration of 100 μM. Then the standard curve and sample were preparedError! Reference source not found.. Vortex solution for ten minutes at room temperature. Centrifuge solution for ten minutes at 16,000 rcf at room temperature. Remove the supernatant immediately into a glass vial for analysis.

183 30124-WO-PCT [00837] Preparation of sample. Add phosphate-buffered saline and DMSO to sample to 6 mg/mL with 15% (v/v) DMSO. Then mix 30 µL 6 mg/mL sample with 45 μL solvent I (sample: precipitant 1:1.5v/v). Vortex solution for ten minutes at room temperature. Centrifuge solution for ten minutes at 16,000 rcf at room temperature. Remove the supernatant immediately into a glass vial for analysis. TABLE 52 RP-HPLC parameters for free drug determination Column: Luna Omega 1.6 μm Polar C18100Å Detection Wavelength: 196nm Column Oven Temp.: 30°C Sampler Temp.: 2~8℃ Flow Rate: 0.4 mL/min Injection Volume: 40 μL Mobile Phases: A: 0.1% TFA in water B: 0.1% TFA in ACN Gradient Program Twenty-eight minutes Gradient Time (min) B (%) 0.00 5.00 20.00 35.00 20.01 90.00 23.00 90.00 23.01 5.00 28.00 5.00 [00838] Data analysis. Integrated the stand BAR curve injections. Plotted the peak area (Y) as a function of concentration (X), Y=Kx + b. Calculated the slope (k) and intercept (b). [00839] Integrated the related drug peak in the sample. Recorded the sum peak area (Y) and interpolated against the standard curve. Calculated the concentration obtained. _{[00840] Cpayload^ = ,!"# - × dilute^factor} [00841] C_payload = of payload by C18-UPLC [00842] Y = sum peak areas of drug related impurities [00843] k = slope of standard curve [00844] b = intercept of standard curve

184 30124-WO-PCT [00845] Report the relative amount of residual payload in product (%mol/mol) with two decimal place. !,785-7& _{[00846] %mol/mol = ^} )*,785-7& !,785-7& !,#-.$/0 _{∗ 100} _),785-7& ⁺ _)*,#-.$/0 ^∗234 [00847] C18-UPLC (mg/mL). [00848] . [00849] BAR = drug to antibody ratio by LC-MS. [00850] Mw _payload = molecular weight of payload. [00851] Mw _protein = molecular weight of mAb. [00852] Hydrophobicity determination by hydrophobic interaction chromatography-HPLC. Hydrophobic Interaction Chromatography was performed using an Agilent 1260 series HPLC system with the TSK gel butyl-nonporous hydrophobic interaction chromatography column (4.6×35 mm, 5 µm) at 25°C. The mobile phase A was consisted of 1.5 M (NH₄)₂SO₄ and 50 mM K₂HPO_4·3H₂O, at pH 7.2±0.2, Cond.190,000±200 us/cm. The mobile phase B was consisted of 50 mM potassium phosphate and 25% 2-propanol, at pH 7.4±0.2, Cond.3400±200 us/cm. The flow rate was set at 0.6 mL/min. Sample loading was 8 μL per injection. Samples were detected at 280 nm with an ultraviolet detector. TABLE 53 HIC-high performance liquid chromatography parameters Column TOSOH, TSKgel butyl-nonporous, 2.5 μm, 4.6 * 35 mm Detection 280 nm BW 4 Column Oven Temp.: 25°C Sampler Temp.: 6 ± 2°C Flow Rate: 0.6 mL/min Stop Time: Twenty minutes Maximum Pressure: 300 bar Injection Amount: 8 µL Mobile Phases: Mobile Phase A: 1.5 M (NH₄)₂SO₄ and 50 mM K₂HPO₄·3H₂O Mobile Phase B: 50 mM potassium phosphate and 25% 2-propanol Gradient Program: Time (min) A (%) B (%) 0 100 0 2 100 0 15 0 100 16 0 100

185 30124-WO-PCT TABLE 53 HIC-high performance liquid chromatography parameters 17 100 0 20 100 0 [00853] Endotoxin determination. The endotoxin level was determined by kinetic turbidimetric assay. [00854] (1) Preparation of endotoxin standards and quality control: The CSE (10EU/vial, lyophilized） is reconstituted with 1 mL of Water for BET to yield a 10 EU/mL standard solution. Make 10-fold dilution using the Water for BET, prepare standard solutions with four concentrations (S1_10 EU/mL, S2_1 EU/mL, S3_0.1 EU/mL, S4_0.01 EU/mL). Dilute CSE with Water for BET to prepare quality control (0.05 EU/mL). [00855] (2) Preparation of TAL Reagents: The TAL reagent is stable when stored at 2~8℃ before expiration. Allow reagents to equilibrate to room temperature prior to use. Added 1.25 mL Water for BET to dissolve 1 bottle of TAL reagent. [00856] (3) Preparation of Samples: diluted all the sample X/2 folds with Water for BET. Taken half volume of X/2 folds sample and added equal volume of Water for BET to make the finally tested sample with X folds dilution. Added equal volume of S3 in the remaining half of volume of X/2 folds sample to make its PPC sample with endotoxin concentration to quality control. [00857] (4) Add 100 μL of the standard curve, quality control, sample, PPC and NTC into wells. Add 100 μL of TAL reagent into the 96-well plat wells(Greiner-655185). All standards control and samples need duplicate. Read microplate with a plate reader. [00858] (5) OD 405 nm was read during incubating at 37^oC for 100 min in a microplate reader. [00859] (6) A standard curve was prepared by plotting the average 405nm measurement for each standard vs. its endotoxin level in EU/mL. [00860] The standard curve was used to determine the endotoxin level of samples. Conjugation methods. [00861] Conjugation buffer and formulation buffer. AGN579, conjugation buffer 50 mM HEPES, pH7.4, and formulation buffer: phosphate-buffered saline, pH 7.4. [00862] Procedure of bulk conjugation. ABT818 in original buffer (phosphate-buffered saline, pH7.4) was buffer exchanged to 50 mM HEPES, pH7.4 by Amicon® Ultra Centrifugal Filter Unit. Concentration was tested with 12.36 mg/mL by Nanodrop.

186 30124-WO-PCT [00863] 140 mg of antibody was transferred to 50mL tube (Greiner, GN227270) and placed in ice bath; then added with conjugation buffer (50 mM HEPES, pH7.4) and 10 mM TBT307 solution (4.59 equivalents). The total DMSO concentration in the reaction mixture was 3.48%; the concentration of the reaction is 10 mg/mL. The reaction vessel was then incubated at 4^oC for five hours followed by 20^oC for thirty-nine hours. [00864] The crude conjugation was purified with UF/DF (Pellicon 3, 30 kDa, 0.11m2) with phosphate- buffered saline, pH7.4 (Gibco, 10010031), 10% DMSO (Sigma, D4540) for 40 DV, followed by phosphate- buffered saline, pH7.4 for 20 DV. [00865] The purified sample was filtered with 0.22 µm filter. [00866] Perform the quality control test (including concentration, size exclusion chromatography - high performance liquid chromatography, hydrophobic interaction chromatography-high performance liquid chromatography, LC-MS, free drug, endotoxin level). [00867] Results and discussion of bulk conjugation. The reaction condition of bulk conjugation is summarized below. After conjugation, the reaction mixture is purified with UF/DF (Pellicon 3, 30 kDa, 0.11m2) with phosphate-buffered saline, pH 7.4 (Gibco, 10010031) contain 10% DMSO (Sigma-Aldrich) for 40 DV and followed by phosphate-buffered saline, pH7.4 for 20 DV. Then filter with 0.22 μM membrane. TABLE 54 Reaction condition for bulk conjugation # Drug/mAb Conjugation Conjugation temp.& time Conjugation ratio Conc.(mg/mL) pH AGN579 ABT818- 3 10 4^oC, five hours & 20^oC, 7.4 TGT307 thirty-nine hours TABLE 55 Molecular information of AGN579 # BAR2 Molecular weight Modification Theoretical Measured Difference (Amino acid, Da) Mass (Da) Mass (Da) (Da) AGN579 135484.02 -K*2, N-Glycan, 135492.13 135495.52 3.39 BAR2

187 30124-WO-PCT TABLE 56 # UV Conc. MS- BAR2% SEC- Residual Residual Residual Endo (mg/mL) BAR (LCMS) Purity uABT (%) Reagent Payload (EU/mg) (%) (%) (%) AGN579 8.44 1.88 81.02 98.88 <2.34 <1.23 <0.70 <0.095 [00868] Results and discussion of stability tests. Store the sample under -70°C for one hour to ensure that material is frozen, then the material is allowed to thaw by letting the vial to sit at room temperature for sufficient amount of time until completed thawed. Collect the analytical characterization under different freeze-thaw cycles (1, 2, 3). TABLE 57 Results for freeze-thaw stability tests Sample Time point (cycles) Conc.(mg/mL) SEC purity (%) BAR AGN579 1 8.63 98.01 1.89 2 8.64 98.91 1.90 3 8.73 98.92 1.90 [00869] Summary. The AGN579 was successfully generated. All the results meet targeting quality. Sample was stable under three freeze-thaw cycles. EXAMPLE 22 Anti-PLA2R TR-FRET assay Materials: [00870] Stock Buffers: HEPES pH 7.5 (1 M), sodium chloride (5 M), calcium chloride (1 M), Tween-20 (10%), and DTT (1 M). [00871] Assay components: [00872] Biotin-Avi-ASGPR1 (ASGPR1-10: 148-291) (3.86 mg/mL; 205.8 µM). [00873] Rabbit anti-PLA2R Abcam AB211573 (1.22 mg/mL; 7.22 µM). [00874] Donor: Streptavidin-Europium cryptate Revvity 610SAKLA (733 nM). [00875] Acceptor: Anti-rabbit IgG d2 Revvity 61PARDAA (250 ug/mL; 1.66 µM). [00876] 384 well PP 2.0 Microplate Echo qualified (Labcyte PP-0200). [00877] Proxiplate 384 (Revvity 6007290). Conditions: [00878] 20 µL final.

188 30124-WO-PCT [00879] [Biotin-Avi-ASGPR1] : 25 nM. [00880] [Rabbit anti-PLA2RR] : 3.1 nM. [00881] [Europium Donor] : 3 nM. [00882] [IgG d2 Acceptor] : 10 M. [00883] Assay buffer: 25 mM HEPES pH 7.5, 150 mM sodium chloride, 5 mM calcium chloride, 0.01% Tween-20, 1 mM DTT. [00884] Streptavidin Europium cryptate donor Ex/Em: 320/620 nm. [00885] Anti-rabbit IgG d2 acceptor Ex/Em: 615/665 nm. Protocol outline [00886] Make fresh assay buffer. [00887] Prepare compound dilutions and use Echo to dispense 180 nL fixed positive control, DMSO, and titrated compounds to 384-well ProxiPlate. [00888] Seal plate. [00889] Prepare 2x mix of anti-PLA2R and ASGPR1 and dispense 10 µl in respective wells in plate with compounds. Seal plate, spin, and incubate for one hour at room temperature. [00890] Prepare 2x TR-FRET donor/acceptor pair and dispense 9 µl in all wells of plate. Seal plate, spin, and incubate for one hour at room temperature. [00891] Read plate. TABLE 58 Degraders TR-FRET (ASGPR) IC₅₀ (µM) Notes AGN306 19.4 AGN308 0.12 AGN307 5.8 AGN309 5.8 AGN310 60.7 AGN364 3.4 AGN364 3.4 AGN365 0.16 AGN365 0.12 AGN579 1.8 Poor fit AGN579 >10 Not concentrated enough EXAMPLE 23 In vivo subcutaneous/intravenous bioavailability study [00892] Study objectives: Subcutaneous bioavailability is highly desired. [00893] Three degrader assays: AGN364, AGN365, and AGN579.

189 30124-WO-PCT [00894] Two routes of administration: intravenous and subcutaneous. [00895] Two doses: 2 mg/kg and 20 mg/kg. [00896] Twelve study groups. N = three per time point. [00897] Time points: one-eighth, one-quarter, one-half, one, two, four, eight, and twenty-four hours. [00898] Mouse assays: Four bleeds per mouse (using retro-orbital bleeding technique) = six mice per group to achieve n = 3. Seventy-two mice for all twelve groups.288 samples total. [00899] Establishing PLA2R pharmacokinetics assay: Degrader calibrators and setup optimization. [00900] Detection of pharmacokinetics assay degrader using soybean agglutinin (SBA) lectin on Strep Avidin Meso Scale Discovery (MSD) plate. [00901] The assay used soybean agglutinin (SBA) lectin bound to a streptavidin-coated Meso Scale Discovery (MSD) plate to capture the PLA2R degrader. Detection was achieved using an anti-PLA2R antibody, followed by a sulfo-tagged anti-rabbit secondary antibody. The inventors used these results to prepare PLA2R degrader standard curves. [00902] Pharmacokinetic Meso Scale Discovery (MSD) assay results: subcutaneous compared with intravenous. [00903] Pharmacokinetic Meso Scale Discovery (MSD) assay results: 20 mg/kg intravenous [00904] Summary. Proceeding with pharmacodynamics assays: AGN365 at 20 mg/kg intravenous. AGN36420 mg/kg intravenous. EXAMPLE 24 Internalization trend of monoclonal antibodies mirrors Meso Scale Discovery (MSD) binding results [00905] Assay conditions: ASGPR-HEK293, 12.5 nM anti-PLA2R, twenty-four hours. ASGPR-HEK293, 25 nM anti-PLA2R, for forty-eight hours. [00906] All degraders containing CysR were internalized, but not that with the 31-mer or the baits. The degraders containing CysR-CTLD1 were internalized, but not those with CysR alone or the 31-mer or the baits. [00907] AGN579 (CysR-CTLD1 Fc fusion) is the most potent degrader. [00908] Rank order: AGN579>>> AGN364>> AGN167 > AGN365

190 30124-WO-PCT EXAMPLE 25 Internalization of anti-PLA2R with next degraders [00909] Internalization trend of monoclonals mirrors Meso Scale Discovery (MSD) binding results. Internalized by all degraders containing CysR, but not that with the 31-mer or the baits. Only internalized by degraders containing CysR-CTLD1, but not those with CysR alone or the 31-mer or the baits. [00910] AGN579 (CysR-CTLD1 Fc fusion) is the most potent degrader. [00911] Internalization assay: Repeat with technical replicates to obtain EC₅₀. [00912] Compare epitope specificity with patient autoantibodies. [00913] Idiopathic membranous nephropathy patient antibodies [00914] Confirm binding to AGN167 (CysR-CTLD1 maleimide degrader) [00915] Isolate from serum for possible use in in vitro and in vivo studies. EXAMPLE 26 Analysis of rabbit Anti-PLA2R monoclonal antibodies [00916] The inventors evaluated binding of CysR or CTLD1-specific clones against degrader to identify antibodies to be used in mouse pharmacodynamics studies and as a detection reagent for pharmacokinetics analysis. [00917] Screening mAbs for pharmacokinetics assay with PLA2R degraders on biotinylated soybean agglutinin (SBA)-coated streptavidin Meso Scale Discovery (MSD) plates. [00918] Following an initial monoclonal antibody screening, a comparative evaluation of five CysR- specific monoclonal antibodies (mAbs) and a polyclonal antibody against PLA2R degraders identified a lead Monoclonal antibody for pharmacokinetics/pharmacodynamics assays. Selection focused on achieving equal or superior binding affinities to the CysR domain and consistent binding across all degraders than the polyclonal antibodies. [00919] Screening monoclonal antibodies for pharmacokinetics assay with PLA2R degraders on biotinylated soybean agglutinin (SBA)-coated streptavidin Meso Scale Discovery (MSD) plates. EXAMPLE 27 [00920] Purpose of assay: Ternary complexes were assayed using both CysR and CysR-CTLD1 degraders. Some signal for CysR bait protein was assayed for AGN364, AGN365, ABT817 (CysR), and ABT819 (CysR-CTLD1). The inventors compared the three antibodies using AGN364 or AGN365 as a

191 30124-WO-PCT control. The dose-dependent signal was more comparable for both degraders than for the other antibodies. [00921] Takeaways: CysR-CTLD1 degrader forms ternary complex with polyclonal antibodies. EXAMPLE 28 PLA2R degrader peptide mapping of AGN364, AGN365, and AGN579 AGN364 was digested by trypsin and the peptide mapping coverage is 59.6%. The unidentified peptides were either digested into very small sizes (<= 4AA) or very big sizes ( 64~94). The C-term peptide was not observed possibly due to it low ionization efficiency. The N-glycosylation site possibly at N73, located at a big tryptic peptide, was not identified by mass spectrometry. TABLE 59 AGN364 PTM sites Modifications Peptides T103, S109, T117, S121 GalNac, GalNac, GalNac, MITGPLQYSVQVAHDNTVVASR GalNac-6GGn-3G [00923] AGN365 was digested by trypsin and the peptide mapping coverage is 60.4% The unidentified peptides were either digested into very small sizes (<= 4AA) or very big sizes ( 64~94, 216~260, 267~322). Conjugation site was located at C terminal Gly361. The N-glycosylation site possibly at N73, located at a big tryptic peptide, was not identified by mass spectrometry. TABLE 60 AGN365 PTM sites Modifications Peptides S109, T117, S121 GalNac MITGPLQYSVQVAHDNTVVASR T203 GalNac-6S-3SG WGFCPDPTSAEVGCDTIWEK G361 triGalNac [00924] AGN579 was digested by trypsin and the peptide mapping coverage is 67.3%. unidentified peptides are either digested into very small sizes (<= 4AA) or very big sizes ( 64~94, 216~260, 267~322). The conjugation site is K385. The Fc N-glycosylation site is N434. TABLE 61 AGN579 PTM sites Modifications Peptides K385 triGalNac THTCPPCPAPEAAGGPSVFLFPPKPKDTLMISR N434 N-glycoforms EEQYNSTYR

192 30124-WO-PCT EXAMPLE 29 TABLE 62 Monoclonal antibody screening (SPR) Tool Binding entity Immobilization Rmax (RU) K_D (nM) Notes mAb level 6A5-8 ABT817 (CysR- 464.2 12.7 32.7 Low signal and active sortase-his) surface seen for analyte 6A5-8 ABT976 (CysR- 464.2 11.4 >1000 Low signal and active CTLD1 no tag) surface seen for analyte 6A5-8 ABT427 (FnII- 464.2 12.8 104 Low signal and active CTLD1-his) surface seen for analyte 6_B3-1 ^{ABT817 (CysR-} _{455.2 181.6 <0.97} ^{Binds to analyte} sortase-his) (preference for CysR) 6B3-1 ABT976 (CysR- 455.2 143.6 6.18 Binds to analyte CTLD1 no tag) (preference for CysR) 6B3-1 ABT427 (FnII- 455.2 81.0 13.8 Binds to analyte CTLD1-his) (preference for CysR) 9A12-1 ABT817 (CysR- 369.7 0 NA No binding sortase-his) 9A12-1 ABT976 (CysR- 369.7 14.0 131 Low active surface CTLD1 no tag) 9A12-1 ABT427 (FnII- 369.7 5.7 205 Low active surface CTLD1-his) (preference for FnII/CTLD1) 9D10-1 ABT817 (CysR- 438.5 93.8 4.69 Binds to analyte (slight sortase-his) preference for CysR) 9D10-1 ABT976 (CysR- 438.5 158.9 12 Binds to analyte CTLD1 no tag) 9D10-1 ABT427 (FnII- 438.5 76.4 45.5 Binds to analyte CTLD1-his) 12A2-1 ABT817 (CysR- 465.3 0 NA No binding sortase-his) 12A2-1 ABT976 (CysR- 465.3 69.2 278 CTLD1 no tag) 12A2-1 ABT427 (FnII- 465.3 22.5 225 Binding preference for CTLD1-his) FnII/CTLD1

193 30124-WO-PCT TABLE 62 Monoclonal antibody screening (SPR) Tool Binding entity Immobilization Rmax (RU) K_D (nM) Notes mAb level 20D11-1 ABT817 (CysR- 476.3 61.1 22.6 Binds to analyte (slight sortase-his) preference for CysR) 20D11-1 ABT976 (CysR- 476.3 97.1 72.4 Binds to analyte CTLD1 no tag) 20D11-1 ABT427 (FnII- 476.3 53.0 119 Binds to analyte CTLD1-his) 47E6-1 ABT817 (CysR- 445.8 100.7 3.81 Binds to analyte (slight sortase-his) preference for CysR) 47E6-1 ABT976 (CysR- 445.8 166.7 9.66 Binds to analyte CTLD1 no tag) 47E6-1 ABT427 (FnII- 445.8 79.1 38.2 Binds to analyte CTLD1-his) 47E7-1 ABT817 (CysR- 449.2 0 NA No binding sortase-his) 47E7-1 ABT976 (CysR- 449.2 144.3 7.19 CTLD1 no tag) 47E7-1 ABT427 (FnII- 449.2 78.6 15.5 Binding preference for CTLD1-his) FnII/CTLD1 2C6-1 ABT817 (CysR- 467.8 0 NA No binding sortase-his) 2C6-1 ABT976 (CysR- 467.8 1.1 54.3 Low signal and active CTLD1 no tag) surface seen 2C6-1 ABT427 (FnII- 467.8 0 NA No binding CTLD1-his) 4F6-1 ABT817 (CysR- 550.1 99.9 31.4 Binds to analyte sortase-his) (preference for CysR). 4F6-1 ABT976 (CysR- 550.1 146.7 323 Binds to analyte CTLD1 no tag) 4F6-1 ABT427 (FnII- 550.1 86.5 260 Binds to analyte CTLD1-his) Approx. Rmax for ABT817 (CysR) (based on 450 RU immobilized): 126. Approx. Rmax for ABT976: 252 Approx. Rmax for ABT427: 144

194 30124-WO-PCT EXAMPLE 30 Conjugation summaries Conjugation process protocol for AGN364 (ABT817-TBT544) and AGN365 (ABT819-TBT544). Conjugation conditions Antibody ABT817 (CysR) ABT817 (CysR) ABT819 (CysR- ABT819 (CysR- CTLD1) CTLD1) Drug TBT544 TBT544 TBT544 TBT544 Sortase PT-0008 PT-0008 PT-0008 PT-0008 Scale (mg) 2 2 2 2 Drug eq./Ab 8 16 8 16 Sortase eq./Ab 0.01 0.01 0.01 0.01 Ab Conc. (mg/mL) 7.87 7.87 7.38 7.38 Conj. Conc. (mg/mL) 3 3 3 3 Organic solvents % 3.21% DMSO 6.43% DMSO 1.45% DMSO 2.89% DMSO Conjugation Buffer 50 mM HEPES, 50 mM HEPES, 50 mM HEPES, 50 mM HEPES, 150 mM sodium 150 mM sodium 150 mM sodium 150 mM sodium chloride,10% chloride,10% chloride,10% chloride,10% glycerol, pH 7.5 glycerol, pH 7.5 glycerol, pH 7.5 glycerol, pH 7.5

195 30124-WO-PCT TABLE 63 Conjugation conditions Temperature and time 4℃, 42 hours 4℃, overnight 4℃, 42 hours 4℃, 42 hours TABLE 64 Conjugation conditions - Results Agent Conjugate Sortase 4℃, 4℃, 4℃, 4℃, 42 4℃, 42 hours- overnight overnight- twenty- hours zeba zeba four hours AGN ABT817-TBT544 PT-0008 0.92 - 0.94 0.93 0.94 AGN ABT817-TBT544 PT-0008 0.99 0.98 - - - AGN ABT819-TBT544 PT-0008 0.77 - 0.79 0.79 0.79 AGN ABT819-TBT544 PT-0008 0.87 - 0.88 0.87 0.87 [00925] C-terminal ligation was performed for ABT817-TBT544 and ABT819-TBT544 with provided conditions. Increasing drug ratio from eight to sixteen increased the final BAR value for two conjugates. ABT817-TBT544 reached BAR 0.99 after 4℃ overnight and didn’t change with prolonged time. ABT819- TBT544 reached slightly lower BAR value 0.87 after 4℃ overnight and didn’t change with prolonged time. Zeba desalting to phosphate-buffered saline buffer didn’t influence BAR value. [00926] Size exclusion chromatography results: ABT817-TBT544 and ABT819-TBT544. Zeba desalting to phosphate-buffered saline buffer didn’t influence size exclusion chromatography purity. Both conjugates achieved size exclusion chromatography purity over 95%. TABLE 65 LC-MS results ABT817-TBT544 Sample ID Sortase Condition BAR value (001) BAR value (002) ABT817-TBT544 PT-0008 4℃, overnight 0.92 0.99 ABT817-TBT544 PT-0008 4℃, twenty-four hours 0.94 ABT817-TBT544 PT-0008 4℃, 42 hours 0.93 ABT817-TBT544 PT-0008 4℃, 42 hours-zeba 0.94 0.98

196 30124-WO-PCT TABLE 66 LC-MS results ABT819-TBT544 Sample ID Sortase Condition BAR value (001) BAR value (002) ABT819-TBT544 PT-0008 4℃, overnight 0.77 0.87 ABT819-TBT544 PT-0008 4℃, twenty-four 0.79 0.88 hours ABT819-TBT544 PT-0008 4℃, 42 hours 0.79 0.87 ABT819-TBT544 PT-0008 4℃, 42 hours-zeba 0.79 0.87 [00927] C-terminal ligation was performed for ABT817-TBT544 and ABT819-TBT544 with provided conditions. Increasing drug ratio from eight to sixteen could increase final BAR value for two conjugates. ABT817-TBT544 reached BAR 0.99 after 4℃ overnight and didn’t change with prolonged time. ABT819- TBT544 reached slightly lower BAR value 0.87 after 4℃ overnight and did not change with prolonged time. [00928] Both conjugates achieved size exclusion chromatography purity over 95%. Neither BAR value nor size exclusion chromatography purity were influenced by Zeba desalting to phosphate- buffered saline buffer after conjugation. TABLE 67 Sortase A project Agent Antibody Mate Reagent Target AGN364 ABT817 (CysR) TBT544 100mg scale, BAR1 AGN365 ABT819 (CysR-CTLD1) TBT544 100mg scale, BAR1 TABLE 68 Reaction conditions Antibody ABT817 (CysR) ABT819 (CysR-CTLD1) Drug TBT544 TBT544 Sortase PT-0008 PT-0008 Scale (mg) 100 100 Drug eq./Ab 16 16

197 30124-WO-PCT TABLE 68 Reaction conditions Sortase eq./Ab 0.01 0.01 Ab Conc. (mg/mL) 3 3 Solvent 4% DMSO 4% DMSO Conjugation Buffer 50 mM HEPES, 150 mM sodium 50 mM HEPES, 150 mM sodium chloride, 10% glycerol (V/V), pH 7.5 chloride, 10% glycerol (V/V), pH 7.5 Temp. & Time 4℃, overnight 4℃, overnight TABLE 69 Quality control results # Ab Scale (mg) Conc. (mg/mL) Amount (mg) Yield (%) MS-BAR SEC Purity(%) AGN364 100 10.86 69.40 69.40 1.00 99.05 AGN364 100 10.41 69.12 69.12 0.99 98.79 Formulation buffer: phosphate-buffered saline, 2 mM EDTA, pH7.4 [00929] Competitive binding of PLA2R constructs (50 nM) and PLA2R autoantibodies in patient serum against full-length PLA2R. TABLE 70 Meso Scale Discovery (MSD) analysis: Detection of PLA2R Ab binding against PLA2R constructs Anti-PLA2R Ab ABT817 (CysR) ABT819 (CysR-CTDL1) ABT305 (31-mer) # Goat Anti- Goat Anti- Goat Anti- Goat Anti- Goat Anti- Goat Anti- Human Rabbit Human Rabbit Human Rabbit ABT985 Rabbit F_ab, Human IgG4_FC ~0.007 ~0.009 ~0.0150 ~0.0140 ~0.0045 ~0.0065

198 30124-WO-PCT TABLE 71 Meso Scale Discovery (MSD) analysis: Detection of PLA2R Ab binding against PLA2R Constructs Anti-PLA2R Ab, EC₅₀ (µg/mL) ABT817 (CysR) ABT819 (CysR-CTDL1) ABT305 (31-mer) E21-Q66 Rabbit Polyclonal Ab 0.0018 ~0.0015 ~0.0019 EPR20483 Rabbit Monoclonal Ab ~0.0021 ~0.0021 ~0.002 ABT985 Rabbit Fab, Human IgG4FC ~0.013 ~0.015 ~0.019 E21-Q66 Rabbit Polyclonal Ab ~0.008 ~0.006 ~0.015 ABT983 Rabbit Fab, Mouse IgG1FC ~0.020 ~0.014 ~0.012 EXAMPLE 31 TABLE 72 # Type Construct Amino acid range ABT606 Antibody Abcam anti-rabbit PLA2R mAb ABT816 Fc-fusion CysR hIgG1 Fc-fusion 21-172, human IgG1 Fc Protein ABT817 Protein CysR Sortase 21-172 ABT818 Fc-fusion CysR-CTLD1 hIgG1 Fc-fusion 21-367, human IgG1 Fc Protein ABT819 Protein CysR-CTLD1 sortase 21-367 ABT976 Protein CysR-CTLD1 + Thrombin 21-367 ABT6977 Protein CTLD7 1108-1234 ABT6978 Protein Full ECD minus CysR 171-1397. The inventors did not choose for further development. ABT6979 Protein Full ECD + Thrombin to cleave 21-165/thrombin/172-1397 CysR (166-171) *full length protein* ABT6980 Protein Full ECD minus CysR-CTLD1 369-1397 ABT6981 Protein Full ECD + Thrombin to cleave 21-364/thrombin/371-1397 CysR-CTLD1 ABT6983 Antibody Anti-PLA2R Biotinylated Mouse Rabbit Fab, Murine IgG1 Fc Chimera ABT6985 Antibody Anti-PLA2R Human Chimera Rabbit Fab, Human IgG4 Fc ABT7300 Protein Full ECD + Thrombin to cleave 21-1397. The inventors did not CysR (161-166) choose for further development.

199 30124-WO-PCT TABLE 72 # Type Construct Amino acid range ABT7301 Protein Full ECD + Thrombin to cleave 21-1397. The inventors did not CysR (183-188) choose for further development. AGN364 Degrader CysR BGN3 21-172 AGN365 Degrader CysR-CTLD1 BGN3 21-367 ABT427 Protein CysR-CTLD1 + thrombin to cleave 21-165/thrombin/172-367 CysR (166-171) ABT7428 Protein CysR-CTLD1 +Thrombin to cleave 21-230/thrombin/237-367 The CysR+FnII (231-236) inventors did not choose for further development. ABT740 Protein CysR-CTLD1, GGGGS-His-GGGGS- 21-367 Cys ABT7408 Protein CysR-CTLD1, GGGGS-His-Cys 21-367 ABT7409 Protein CysR-CTLD1-GGGGS-His-GGGE- 21-367 Cys-S AGN579 Degrader CysR-CTLD1-Fc BGN3 21-367 ABT7607 Protein CysR-CTLD3 Sortase 21-656 ABT7608 Protein CysR-CTLD3 Fc-fusion 21-656 ABT7609 Protein CysR-CTLD5 Sortase 21-946 ABT7610 Protein CysR-CTLD5 Fc-fusion 21-946 ABT7611 Protein CysR-CTLD7 Sortase 21-1237 ABT7612 Protein CysR-CTLD7 Fc-fusion 21-1237 ABT7613 Protein CysR-CTLD8 Sortase 21-1397 ABT7614 Protein CysR-CTLD8 Fc-fusion 21-1397 ABT7617 Protein CysR Fc-fusion (K123R, K127R, 21-172 K144R) ABT7688 Protein CysR, GGGGS-His-GGGGS-Cys 21-172 ABT7689 Protein CysR, GGGGS-His-Cys 21-172 ABT7690 Protein CysR, GGGGS-His-GGGE-Cys-S 21-172

200 30124-WO-PCT TABLE 73 # Tag Mutant Expression Notes system ABT606 CHO ABT816 N/A LALA/PA CHO K1 For conjugation ABT817 C-term Sortase- wild-type CHO K1 For conjugation His6 ABT818 N/A LALA/PA CHO K1 For conjugation ABT819 C-term sortase- wild-type CHO K1 For conjugation His6 ABT976 C-term thrombin wild-type HEK293 For immunization site-His6 (cleave his tag) ABT6977 C-term Avi-His10 wild-type HEK293 ABT6978 C-term Avi-His10 wild-type HEK293 The inventors did not choose for further development. Did not express well. ABT6979 C-term Avi-His10 wild-type with HEK293 Did not cleave- engineered thrombin site use as full-length from 166-171 protein ABT6980 C-term Avi-His10 wild-type HEK293 ABT6981 C-term Avi-His10 wild-type HEK293 ABT6983 HC Avi CHO K1 Biotinylated antibody for mouse studies ABT6985 N/A S to P mutation in hinge CHO K1 (Fab arm exchange) ABT7300 C-term Avi-His10 wild-type with HEK293 The inventors did engineered thrombin site not choose for from 161-166 further development. Did not express well. ABT7301 C-term Avi-His10 wild-type with HEK293 The inventors did engineered thrombin site not choose for from 183-188 further development. Did not express well.

201 30124-WO-PCT TABLE 73 # Tag Mutant Expression Notes system AGN364 BGN3 CHO K1 Sortase conjugation AGN365 BGN3 CHO K1 Sortase conjugation ABT427 C-term His6 wild-type with HEK293 engineered thrombin site from 166-171 ABT7428 C-term His6 wild-type with HEK293 The inventors did engineered thrombin site not choose for from 231-236 further development. Did not express well. ABT740 C-term His6 and wild-type HEK293 Cys ABT7408 C-term His6 and wild-type HEK293 Cys ABT7409 C-term His6 and wild-type HEK293 Cys AGN579 N/A ABT7607 C-term Sortase wild-type CHO K1 site-His6 ABT7608 N/A wild-type CHO K1 ABT7609 C-term Sortase wild-type CHO K1 site-His6 ABT7610 N/A wild-type CHO K1 ABT7611 C-term Sortase wild-type CHO K1 site-His6 ABT7612 N/A wild-type CHO K1 ABT7613 C-term Sortase wild-type CHO K1 site-His6 ABT7614 N/A wild-type CHO K1 ABT7617 N/A K123R, K127R, K144R CHO K1 ABT7688 C-term His6 and wild-type CHO K1 Cys

202 30124-WO-PCT TABLE 73 # Tag Mutant Expression Notes system ABT7689 C-term His6 and wild-type CHO K1 Cys ABT7690 C-term His6 and wild-type CHO K1 Cys EQUIVALENTS [00930] persons having ordinary skill in the biomedical art will recognize or be able to determine using no more than routine experimentation many equivalents to the specific procedures described in this specification. Such equivalents are within the scope of this invention and are covered by these claims. For example, pharmaceutically acceptable salts other than those specifically revealed in the description and Examples in this specification can be employed. Furthermore, it is intended that specific items within lists of items, or subset groups of items within larger groups of items, can be combined with other specific items, subset groups of items or larger groups of items whether or not there is a specific disclosure in this specification identifying this combination. [00931] Some embodiments of the invention can be practiced according to the following numbered paragraphs: [00932] 1. A composition of matter comprising: an anti-PLA2R antibody-binding moiety, a cellular receptor-binding moiety capable of binding to hepatocytes or other degrading cells through asialoglycoprotein receptors (ASGPR) of hepatocytes or other cell receptors on surface degrading cells, and a linker moiety (optionally a single peptide linkage) connecting the anti-PLA2R antibody-binding moiety and the cellular receptor-binding moiety. [00933] 2. The composition of matter of embodiment 1, wherein the anti-PLA2R antibody-binding moiety is a published anti-PLA2R antibody ligand variant antibody, an anti-PLA2R antibody ligand variant, or an antigen-binding fragment thereof. [00934] 3.The composition of matter of embodiment 1, having a structure of:

203 30124-WO-PCT R^CN−(Xaa)y−R^CC, [00935] 4.The composition of matter of embodiment 1, wherein the agent has the structure of formula [AGN102]: , acceptable salt thereof, wherein: each of a and b is independently an integer of 1 or greater; each AT is an anti-PLA2R antibody-binding moiety or a fragment thereof; L is a linker moiety; and each TBT is independently a cellular receptor-binding moiety which binds to hepatocytes or other degrading cells through asialoglycoprotein receptors (ASGPR) of hepatocytes or other cell receptors on the surface degrading cells in a patient or subject, wherein the anti-PLA2R antibody-binding moiety is a ligand variant or an antigen-binding fragment thereof. [00936] 5. The composition of matter of embodiment 1, wherein the agent has the structure of formula AGN105:

204 30124-WO-PCT in the composition of matter has more elements described in this specification. [00937] 6. The composition of matter of embodiment 1, wherein the cellular receptor-binding moiety comprises an ASGPR-binding group according to the chemical structure: R₃ are the same as in embodiment 9, or a pharmaceutically acceptable salt, stereoisomer, solvate or polymorph thereof. [00938] 7. The composition of matter of embodiment 1, wherein the cellular receptor-binding moiety has the following structure: ;

205 30124-WO-PCT where R^A is a C₁-C₃ alkyl group optionally substituted with 1-5 halo (preferably fluoro) groups (preferably R^A is a methyl or ethyl group optionally substituted with from 1-3 fluoro groups); Z_A is - (CH2)IM, -O-(CH2)IM, S-(CH2)IM, NRM-(CH2)IM, C(O)-(CH2)IM-, a PEG group containing from 1 to 8 preferably 1- 4 ethylene glycol residues or a -C(O)(CH₂)_IMNR_M group (preferably a PEG containing group comprising from 1 to 8 ethylene glycol, preferably 2-4 ethylene glycol residues); and Z_B is absent, (CH₂)_IM, C(O)- (CH₂)_IM- or C(O)-(CH₂)_IM-NR_M. [00939] 8. The composition of matter of embodiment 1, wherein the cellular receptor-binding moiety is a low-density lipoprotein receptor-related protein 1 (LRP1), a low-density lipoprotein receptor (LDLR), a FcγRI-binding group, a FcRN-binding group, a transferrin receptor-binding group, or a macrophage scavenger receptor-binding group. [00940] 9. A pharmaceutical composition comprising a composition of matter of embodiments 1-8 and a pharmaceutically acceptable excipient. [00941] 10. A method of removing anti-PLA2R antibody in a subject or patient comprising administering to the subject or patient the agent of any of embodiments 1-8. [00942] 11. A method of treating a disease state or condition associated with the upregulation of anti-PLA2R antibody in a subject or patient administering to the subject or patient an effective amount of the agent of any of embodiments 1-8. [00943] 12. A method of treating idiopathic membranous nephropathy in a patient comprising administering to the patient an effective amount of the agent of any of embodiments 1-8. [00944] 13. A composition comprising: a first composition of matter comprising: an antibody moiety, a cellular receptor-binding moiety which binds to hepatocytes or other degrading cells through asialoglycoprotein receptors (ASGPR) of hepatocytes or other cell receptors on the surface degrading cells in a patient or subject, and a linker moiety linking the antibody moiety and the cellular receptor- binding moiety, and at least one additional composition of matter comprising a moiety capable of binding to the antibody that forms the antibody moiety of the first composition of matter. REFERENCES [00945] Persons having ordinary skill in the biomedical art can use these patents, patent applications, and scientific references as guidance to predictable results when making and using the invention.

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209 30124-WO-PCT [00987] Kruljec et al., Development and characterization of peptide ligands of immunoglobulin G Fc region. Bioconjugate Chem., 29(8), 2763-2775 (July 19, 2018) [00988] Kudose et al., NELL1-associated membranous glomerulopathy after hematopoietic stem cell transplantation. Kidney Int. Rep., 6,1992-1995 (2021). [00989] Kukuy et al., The Prognostic Value of Anti-PLA2R Antibodies Levels in Primary Membranous Nephropathy. Int. J. Mol. Sci., 24, 9051 (2023). [00990] Lai et al., Membranous nephropathy: a review on the pathogenesis, diagnosis, and treatment. J. Formos. Med. Assoc., 114(2), 102-11 (2015). [00991] Lu et al., Plasma exchange and rituximab treatments in primary membranous nephropathy combined with crescentic glomerulonephritis. Medicine (Baltimore), 98(18), e15303 (May 2019). [00992] Luo J et al. Seropositive PLA2R-associated membranous nephropathy but biopsy-negative PLA2R staining. Nephrol. Dial. Transplant. (2020). [00993] Meyer-Schwesinger et al., A novel mouse model of phospholipase A2 receptor 1-associated membranous nephropathy mimics podocyte injury in patients, Kidney International, 97(5), 913-919 (2020). (“Thus, our mouse model of membranous nephropathy will allow investigation of PLA2R1- specific pathomechanisms and may help to develop and assess antigen-specific treatments in vivo.”) [00994] Muguruma et al., Kinetics-based structural requirements of human immunoglobulin G Binding Peptides. ACS Omega, 4, 14390−14397 (August 28, 2019). [00995] Mustafaoglu et al., Antibody purification via affinity membrane chromatography method using nucleotide binding site targeting with a small molecule, Analyst, 141(24), 6571–6582 (November 28, 2016). [00996] Nath, Godat, Flemming &, Urh, Deciphering the interaction between neonatal fc receptor and antibodies using a homogeneous bioluminescent immunoassay. The Journal of Immunology, 207(4), 1211–1221 (2021). [00997] Pettersson & Crews, PROteolysis TArgeting Chimeras (PROTACs) — Past, present and future. In Drug Discovery Today: Technologies, 31, 15–27 (Elsevier BV, 2019). [00998] Ronco, Plaisier, & Debiec, Advances in Membranous Nephropathy. J. Clin. Med.2021, 10, 607. [00999] Rovin et al., KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases. Kidney international, Vol 100, Issue 45, Supplement (October 2021). [001000] Ruggenenti et al., Anti-phospholipase a2 receptor antibody titer predicts post-rituximab outcome of membranous nephropathy. J. Am. Soc. Nephrol., 26(10), 2545–58 (October 2015).

210 30124-WO-PCT [001001] Saxena & Wu, Advances in therapeutic Fc engineering–modulation of IgG-associated effector functions and serum half-life. Frontiers in immunology, 7, 580 (2016) (review). [001002] Shields et al., High resolution mapping of the binding site on human IgG1 for FcγRI, FcγRII, FcγRIII, and FcRn and design of IgG1 variants with improved binding to the FcγR. Journal of Biological Chemistry 276(9), 6591-6604 (2001). [001003] Strohl, Optimization of Fc-mediated effector functions of monoclonal antibodies. Current Opinion in Biotechnology, 20(6), 685-691 (2009). [001004] Sun et al., Analysis of glomerular PLA2R efficacy in evaluating the prognosis of idiopathic membranous nephropathy in the background of different serum anti-PLA2R levels. Renal Failure, 44(1), 731-740 (2023). This reference correlates anti-PLA2R titer and idiopathic membranous nephropathy. [001005] Tamm & Schmidt, IgG binding sites on human Fcγ receptors. International Reviews of Immunology, 16(1-2), 57-85 (1997). [001006] Teng et al., A strategy for the generation of biomimetic ligands for affinity chromatography. Combinatorial synthesis and biological evaluation of an IgG binding ligand, J. Mol. Recognit., 12, 67–75 (1999). [001007] Tilman et al., Novel human IgG1 and IgG4 Fc-engineered antibodies with abolished immune effector functions. Protein Engineering, Design and Selection, Volume 29, Issue 10, pages 457–466 (October 2016). This paper shows that even LALA itself abolishes c1q binding. P329A alone is tested, and abolishes c1q binding, and reduces FcgR binding. They do not test P329A/LALA but show that P329G/LALA further reduces FcgR binding beyond LALA alone. [001008] Uttamchandani et al., Microarrays of tagged combinatorial triazine libraries in the discovery of small-molecule ligands of human IgG, J. Comb. Chem., 6(6), 862-8 (November-December 2004). [001009] van de Logt et al. Immunological remission in PLA2R-antibody-associated membranous nephropathy: cyclophosphamide versus rituximab. Kidney Int.93, 1016–1017 (2018). [001010] Watanabe et al., Human soluble phospholipase A2 receptor is an inhibitor of the integrin- mediated cell migratory response to collagen. Am. J. Physiol. Cell Physiol., 315, C398-C408 (2018). [001011] Wu et al. The prognostic value of phospholipase A2 receptor autoantibodies on spontaneous remission for patients with idiopathic membranous nephropathy: a meta-analysis. Medicine 97, e11018 (2018). [001012] Yamada et al., AJICAP: Affinity peptide mediated regiodivergent functionalization of native antibodies. Angew Chem. Int., Ed Engl., 58(17), 5592-5597 (April 16, 2019).

211 30124-WO-PCT [001013] Yeh et al. Pathogenic human monoclonal antibody against desmoglein 3. Clinical Immunology.120(1), 68-75(2006). [001014] Zalevsky et al. Enhanced antibody half-life improves in vivo activity. Nature Biotechnology, 28(2),157-159 (2010). Textbooks and technical references [001015] The Merck Manual of Diagnosis and Therapy, 19^th edition (Merck Sharp & Dohme Corp., 2018). [001016] Remington’s, Pharmaceutical Sciences 23^rd edition (Elsevier, 2020). [001017] Throughout this application, several publications are referenced by author name and date, or by patent number or patent publication number. The disclosures of these publications are incorporated in their entireties by reference into this application to describe the state of the art more fully as known to persons having ordinary skill in the biomedical art as of the invention described and claimed in this specification. However, the citation of a reference in this specification should not be construed as an acknowledgment that this reference is prior art to the present invention. [001018] All patents and publications cited throughout this specification are incorporated by reference to reveal and describe the materials and methods that might be used with the technologies described in this specification. The publications discussed are provided only for their disclosure before the filing date. They should not be construed as an admission that the inventors may not antedate this disclosure under past invention or for any other reason. If there is an apparent discrepancy between a past patent or publication and the description in this specification, the specification (including any definitions) and claims shall control. All statements about the date or contents of these documents are based on the information available to the applicants. These statements are no admission to the correctness of the dates or contents of these documents. The publication dates in this specification may differ from the actual publication dates. If there is an apparent discrepancy between a publication date in this specification and the actual publication date supplied by the publisher, the actual publication date shall control.

212 30124-WO-PCT SEQUENCE LISTING Sequence Total Quantity: 152 Sequence Number (ID): 1 Length: 17 Molecule Type: AA Features Location/Qualifiers: - source, 1..17 > mol_type, protein > organism, Homo sapiens - PEPTIDE, 1..17 > note, Fragment 1 (major epitope) Residues: WQDKGIFVIQ SESLKKC 17 Sequence Number (ID): 2 Length: 9 Molecule Type: AA Features Location/Qualifiers: - source, 1..9 > mol_type, protein > organism, Homo sapiens - PEPTIDE, 1..9 > note, Fragment 2 (major epitope) Residues: WSVLTENCK 9 Sequence Number (ID): 3 Length: 17 Molecule Type: AA Features Location/Qualifiers: - source, 1..17 > mol_type, protein > organism, Homo sapiens - PEPTIDE, 1..17 > note, Fragment 3 Residues: TREGREDDLL WCATTSR 17

213 30124-WO-PCT Sequence Number (ID): 4 Length: 16 Molecule Type: AA Features Location/Qualifiers: - source, 1..16 > mol_type, protein > organism, Homo sapiens - PEPTIDE, 1..16 > note, Fragment 4 Residues: YLNHIQHEIV EKDAWK 16 Sequence Number (ID): 5 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens - PEPTIDE, 1..15 > note, Fragment 5 Residues: YYATHCEPGW NPYNR 15 Sequence Number (ID): 6 Length: 14 Molecule Type: AA Features Location/Qualifiers: - source, 1..14 > mol_type, protein > organism, Homo sapiens - PEPTIDE, 1..14 > note, Fragment 6 Residues: KEEKTWHEAR LRSC 14 Sequence Number (ID): 7

214 30124-WO-PCT Length: 18 Molecule Type: AA Features Location/Qualifiers: - source, 1..18 > mol_type, protein > organism, Homo sapiens - PEPTIDE, 1..18 > note, Fragment 7 Residues: AGHVLSOAES GCQEGWER 18 Sequence Number (ID): 8 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens - PEPTIDE, 1..15 > note, Fragment 8 Residues: PRYSGGCVAM RGRHP 15 Sequence Number (ID): 9 Length: 31 Molecule Type: AA Features Location/Qualifiers: - source, 1..31 > mol_type, protein > organism, synthetic construct - BINDING, 1..31 > note, epitope Residues: WQDKGIFVIQ SESLKKCIQA GKSVLTLENC K 31 Sequence Number (ID): 10 Length: 6 Molecule Type: AA

215 30124-WO-PCT Features Location/Qualifiers: - source, 1..6 > mol_type, protein > organism, synthetic construct Residues: VIQSES 6 Sequence Number (ID): 11 Length: 9 Molecule Type: AA Features Location/Qualifiers: - source, 1..9 > mol_type, protein > organism, synthetic construct Residues: SVLTLENCK 9 Sequence Number (ID): 12 Length: 152 Molecule Type: AA Features Location/Qualifiers: - source, 1..152 > mol_type, protein > organism, synthetic construct Residues: EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60 LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GN 152 Sequence Number (ID): 13 Length: 347 Molecule Type: AA Features Location/Qualifiers: - source, 1..347 > mol_type, protein > organism, synthetic construct Residues: EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60

216 30124-WO-PCT LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GNTHGMPCMF PFQYNHQWHH ECTREGREDD 180 LLWCATTSRY ERDEKWGFCP DPTSAEVGCD TIWEKDLNSH ICYQFNLLSS LSWSEAHSSC 240 QMQGGTLLSI TDETEENFIR EHMSSKTVEV WMGLNQLDEH AGWQWSDGTP LNYLNWSPEV 300 NFEPFVEDHC GTFSSFMPSA WRSRDCESTL PYICKKYLNH IDHEIVE 347 Sequence Number (ID): 14 Length: 446 Molecule Type: AA Features Location/Qualifiers: - source, 1..446 > mol_type, protein > organism, synthetic construct - VARIANT, 219 > note, Cysteine site can be mutated - SITE, 233..234 > note, LALA sequence - SITE, 328 > note, PA sequence Residues: ELQLQESGPG LVKPSQSLSL TCSVTGYSIR SNYWGWIRKF PGNKMEWMGY ITYSGGTYYN 60 PSLKSRISIT RDTSKNQFFL QLTSVTTEDT ATYYCTRWGD WYFDFWGPGT KVTVSPASTK 120 GPSVFPLAPS SKSTSGGTAA LGCLVKDYFP EPVTVSWNSG ALTSGVHTFP AVLQSSGLYS 180 LSSVVTVPSS SLGTQTYICN VNHKPSNTKV DKKVEPKSXD KTHTCPPCPA PEAAGGPSVF 240 LFPPKPKDTL MISRTPEVTC VVVDVSHEDP EVKFNWYVDG VEVHNAKTKP REEQYNSTYR 300 VVSVLTVLHQ DWLNGKEYKC KVSNKALAAP IEKTISKAKG QPREPQVYTL PPSRDELTKN 360 QVSLTCLVKG FYPSDIAVEW ESNGQPENNY KTTPPVLDSD GSFFLYSKLT VDKSRWQQGN 420 VFSCSVMHEA LHNHYTQKSL SLSPGK 446 Sequence Number (ID): 15 Length: 389 Molecule Type: AA Features Location/Qualifiers: - source, 1..389 > mol_type, protein > organism, synthetic construct - REGION, 153..157 > note, GGGGS linker

217 30124-WO-PCT - MOD_RES, 162 > note, Cysteine modified to adenine - SITE, 176..177 > note, LALA sequence - SITE, 271 > note, PA sequence Residues: EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60 LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GNGGGGSEPK SADKTHTCPP CPAPEAAGGP 180 SVFLFPPKPK DTLMISRTPE VTCVVVDVSH EDPEVKFNWY VDGVEVHNAK TKPREEQYNS 240 TYRVVSVLTV LHQDWLNGKE YKCKVSNKAL AAPIEKTISK AKGQPREPQV YTLPPSRDEL 300 TKNQVSLTCL VKGFYPSDIA VEWESNGQPE NNYKTTPPVL DSDGSFFLYS KLTVDKSRWQ 360 QGNVFSCSVM HEALHNHYTQ KSLSLSPGK 389 Sequence Number (ID): 16 Length: 169 Molecule Type: AA Features Location/Qualifiers: - source, 1..169 > mol_type, protein > organism, synthetic construct - REGION, 164..167 > note, His6 tag - REGION, 158..163 > note, Sortase site - REGION, 153..157 > note, GGGGS linker Residues: EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60 LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GNGGGGSLPE TGGHHHHHH 169 Sequence Number (ID): 17 Length: 584 Molecule Type: AA Features Location/Qualifiers: - source, 1..584

218 30124-WO-PCT > mol_type, protein > organism, synthetic construct - REGION, 348..352 > note, GGGGS linker - MOD_RES, 357 > note, Cysteine modified to adenine - REGION, 360..368 > note, THTCPPCPA - SITE, 371..372 > note, LALA sequence - SITE, 466 > note, PA sequence - REGION, 464..471 > note, ALAAPIEK - MOD_RES, 357..393 > note, SADKTHTCPPCPAPEAAGGPSVFLFPPKPKDTLMISR (K30+GalNacX1)(5+) - MOD_RES, 431..439 > note, EEQYNSTYR (N5+A1G0F)(2+) Residues: EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60 LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GNTHGMPCMF PFQYNHQWHH ECTREGREDD 180 LLWCATTSRY ERDEKWGFCP DPTSAEVGCD TIWEKDLNSH ICYQFNLLSS LSWSEAHSSC 240 QMQGGTLLSI TDETEENFIR EHMSSKTVEV WMGLNQLDEH AGWQWSDGTP LNYLNWSPEV 300 NFEPFVEDHC GTFSSFMPSA WRSRDCESTL PYICKKYLNH IDHEIVEGGG GSEPKSADKT 360 HTCPPCPAPE AAGGPSVFLF PPKPKDTLMI SRTPEVTCVV VDVSHEDPEV KFNWYVDGVE 420 VHNAKTKPRE EQYNSTYRVV SVLTVLHQDW LNGKEYKCKV SNKALAAPIE KTISKAKGQP 480 REPQVYTLPP SRDELTKNQV SLTCLVKGFY PSDIAVEWES NGQPENNYKT TPPVLDSDGS 540 FFLYSKLTVD KSRWQQGNVF SCSVMHEALH NHYTQKSLSL SPGK 584 Sequence Number (ID): 18 Length: 364 Molecule Type: AA Features Location/Qualifiers: - source, 1..364 > mol_type, protein > organism, synthetic construct - REGION, 359..364

219 30124-WO-PCT > note, His6 tag - REGION, 353..358 > note, Sortase site - REGION, 348..352 > note, GGGGS linker Residues: EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60 LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GNTHGMPCMF PFQYNHQWHH ECTREGREDD 180 LLWCATTSRY ERDEKWGFCP DPTSAEVGCD TIWEKDLNSH ICYQFNLLSS LSWSEAHSSC 240 QMQGGTLLSI TDETEENFIR EHMSSKTVEV WMGLNQLDEH AGWQWSDGTP LNYLNWSPEV 300 NFEPFVEDHC GTFSSFMPSA WRSRDCESTL PYICKKYLNH IDHEIVEGGG GSLPETGGHH 360 HHHH 364 Sequence Number (ID): 19 Length: 216 Molecule Type: AA Features Location/Qualifiers: - source, 1..216 > mol_type, protein > organism, synthetic construct Residues: QVLTQTASPV SAAVGGTVTI NCQASQSLYN NKNLAWYQQK PGQPPKLLIY YTATLASGVS 60 SRFEGSGSGT HFTLTISGVQ CDDAATYYCQ GEFTCESADC YTFGGGTEVL VKGDPVAPTV 120 LIFPPAADQV ATGTVTIVCV ANKYFPDVTV TWEVDGTTQT TGIENSKTPQ NSADCTYNLS 180 STLTLTSTQY NSHKEYTCKV TQGTTSVVQS FNRGDC 216 Sequence Number (ID): 20 Length: 455 Molecule Type: AA Features Location/Qualifiers: - source, 1..455 > mol_type, protein > organism, synthetic construct - REGION, 441..455 > note, Avi-tag - REGION, 436..440 > note, GGGGS linker

220 30124-WO-PCT - REGION, 209..221 > note, VPRDAGCKPCICT Residues: QSVEESGGRL VTPGTPLTLT CTVSGFSLSS YAMIWVRQAP GKGLEWIGII YAIGIKYYAN 60 WAKGRFTISK TSTTVDLKIT SPTTEDTATY FCARGDLWGP GTLVTVSSGQ PKAPSVFPLA 120 PCCGDTPSST VTLGCLVKGY LPEPVTVTWN SGTLTNGVRT FPSVRQSSGL YSLSSVVSVT 180 SSSQPVTCNV AHPATNTKVD KTVAPSTCVP RDAGCKPCIC TVPEVSSVFI FPPKPKDVLT 240 ITLTPKVTCV VVDISKDDPE VQFSWFVDDV EVHTAQTQPR EEQFNSTFRS VSELPIMHQD 300 WLNGKEFKCR VNSAAFPAPI EKTISKTKGR PKAPQVYTIP PPKEQMAKDK VSLTCMITDF 360 FPEDITVEWQ WNGQPAENYK NTQPIMNTNG SYFVYSKLNV QKSNWEAGNT FTCSVLHEGL 420 HNHHTEKSLS HSPGKGGGGS GLNDIFEAQK IEWHE 455 Sequence Number (ID): 21 Length: 437 Molecule Type: AA Features Location/Qualifiers: - source, 1..437 > mol_type, protein > organism, synthetic construct - REGION, 209..220 > note, ESKYGPPCPPCP Residues: QSVEESGGRL VTPGTPLTLT CTVSGFSLSS YAMIWVRQAP GKGLEWIGII YAIGIKYYAN 60 WAKGRFTISK TSTTVDLKIT SPTTEDTATY FCARGDLWGP GTLVTVSSGQ PKAPSVFPLA 120 PCCGDTPSST VTLGCLVKGY LPEPVTVTWN SGTLTNGVRT FPSVRQSSGL YSLSSVVSVT 180 SSSQPVTCNV AHPATNTKVD KTVAPSTCES KYGPPCPPCP APEFLGGPSV FLFPPKPKDT 240 LMISRTPEVT CVVVDVSQED PEVQFNWYVD GVEVHNAKTK PREEQFNSTY RVVSVLTVLH 300 QDWLNGKEYK CKVSNKGLPS SIEKTISKAK GQPREPQVYT LPPSQEEMTK NQVSLTCLVK 360 GFYPSDIAVE WESNGQPENN YKTTPPVLDS DGSFFLYSRL TVDKSRWQEG NVFSCSVMHE 420 ALHNHYTQKS LSLSLGK 437 Sequence Number (ID): 22 Length: 474 Molecule Type: AA Features Location/Qualifiers: - source, 1..474 > mol_type, protein > organism, synthetic construct

221 30124-WO-PCT - SIGNAL, 1..19 > note, Signal peptide - PEPTIDE, 49..53 > note, HCDR1 SYAMI - PEPTIDE, 68..83 > note, HCDR2 IIYAIGIKYYANWAKG - PEPTIDE, 460..474 > note, Terminal Avi tag GLNDIFEAQKIEWHE - PEPTIDE, 114..116 > note, HCDR3 GDL - SITE, 52 > note, M is an oxidation site - SITE, 80 > note, W is an oxidation site Residues: MGWSCIILFL VATATGVHSQ SVEESGGRLV TPGTPLTLTC TVSGFSLSSY AMIWVRQAPG 60 KGLEWIGIIY AIGIKYYANW AKGRFTISKT STTVDLKITS PTTEDTATYF CARGDLWGPG 120 TLVTVSSGQP KAPSVFPLAP CCGDTPSSTV TLGCLVKGYL PEPVTVTWNS GTLTNGVRTF 180 PSVRQSSGLY SLSSVVSVTS SSQPVTCNVA HPATNTKVDK TVAPSTCVPR DAGCKPCICT 240 VPEVSSVFIF PPKPKDVLTI TLTPKVTCVV VDISKDDPEV QFSWFVDDVE VHTAQTQPRE 300 EQFNSTFRSV SELPIMHQDW LNGKEFKCRV NSAAFPAPIE KTISKTKGRP KAPQVYTIPP 360 PKEQMAKDKV SLTCMITDFF PEDITVEWQW NGQPAENYKN TQPIMNTNGS YFVYSKLNVQ 420 KSNWEAGNTF TCSVLHEGLH NHHTEKSLSH SPGKGGGGSG LNDIFEAQKI EWHE 474 Sequence Number (ID): 23 Length: 236 Molecule Type: AA Features Location/Qualifiers: - source, 1..236 > mol_type, protein > organism, synthetic construct - SIGNAL, 1..20 > note, Signal peptide - REGION, 43..55 > note, LCDR1 QASQSLYNNKNLA - REGION, 71..77 > note, LCDR2 YTATLAS - REGION, 110..122

222 30124-WO-PCT > note, LCDR3 QGEFTCESADCYT - REGION, 50..51 > note, NN are deamidation sites Residues: METDTLLLWV LLLWVPGSTG QVLTQTASPV SAAVGGTVTI NCQASQSLYN NKNLAWYQQK 60 PGQPPKLLIY YTATLASGVS SRFEGSGSGT HFTLTISGVQ CDDAATYYCQ GEFTCESADC 120 YTFGGGTEVL VKGDPVAPTV LIFPPAADQV ATGTVTIVCV ANKYFPDVTV TWEVDGTTQT 180 TGIENSKTPQ NSADCTYNLS STLTLTSTQY NSHKEYTCKV TQGTTSVVQS FNRGDC 236 Sequence Number (ID): 24 Length: 456 Molecule Type: AA Features Location/Qualifiers: - source, 1..456 > mol_type, protein > organism, synthetic construct - SIGNAL, 1..19 > note, Signal peptide - REGION, 49..53 > note, HCDR1 SYAMI - REGION, 68..83 > note, HCDR2 IIYAIGIKYYANWAKG - REGION, 114..116 > note, HCDR3 GDL - SITE, 80 > note, W is an oxidation site - SITE, 52 > note, M is an oxidation site Residues: MGWSCIILFL VATATGVHSQ SVEESGGRLV TPGTPLTLTC TVSGFSLSSY AMIWVRQAPG 60 KGLEWIGIIY AIGIKYYANW AKGRFTISKT STTVDLKITS PTTEDTATYF CARGDLWGPG 120 TLVTVSSGQP KAPSVFPLAP CCGDTPSSTV TLGCLVKGYL PEPVTVTWNS GTLTNGVRTF 180 PSVRQSSGLY SLSSVVSVTS SSQPVTCNVA HPATNTKVDK TVAPSTCESK YGPPCPPCPA 240 PEFLGGPSVF LFPPKPKDTL MISRTPEVTC VVVDVSQEDP EVQFNWYVDG VEVHNAKTKP 300 REEQFNSTYR VVSVLTVLHQ DWLNGKEYKC KVSNKGLPSS IEKTISKAKG QPREPQVYTL 360 PPSQEEMTKN QVSLTCLVKG FYPSDIAVEW ESNGQPENNY KTTPPVLDSD GSFFLYSRLT 420 VDKSRWQEGN VFSCSVMHEA LHNHYTQKSL SLSLGK 456

223 30124-WO-PCT Sequence Number (ID): 25 Length: 455 Molecule Type: AA Features Location/Qualifiers: - source, 1..455 > mol_type, protein > organism, synthetic construct - REGION, 209..221 > note, VPRDAGCKPCICT - SITE, 213 > note, A - REGION, 441..455 > note, Terminal Avi tag GLNDIFEAQKIEWHE - REGION, 436..440 > note, GGGGS-linker Residues: QSVEESGGRL VTPGTPLTLT CTVSGFSLSS YAMIWVRQAP GKGLEWIGII YAIGIKYYAN 60 WAKGRFTISK TSTTVDLKIT SPTTEDTATY FCARGDLWGP GTLVTVSSGQ PKAPSVFPLA 120 PCCGDTPSST VTLGCLVKGY LPEPVTVTWN SGTLTNGVRT FPSVRQSSGL YSLSSVVSVT 180 SSSQPVTCNV AHPATNTKVD KTVAPSTCVP RDAGCKPCIC TVPEVSSVFI FPPKPKDVLT 240 ITLTPKVTCV VVDISKDDPE VQFSWFVDDV EVHTAQTQPR EEQFNSTFRS VSELPIMHQD 300 WLNGKEFKCR VNSAAFPAPI EKTISKTKGR PKAPQVYTIP PPKEQMAKDK VSLTCMITDF 360 FPEDITVEWQ WNGQPAENYK NTQPIMNTNG SYFVYSKLNV QKSNWEAGNT FTCSVLHEGL 420 HNHHTEKSLS HSPGKGGGGS GLNDIFEAQK IEWHE 455 Sequence Number (ID): 26 Length: 431 Molecule Type: AA Features Location/Qualifiers: - source, 1..431 > mol_type, protein > organism, synthetic construct Residues: QSVEESGGRL VTPGTPLTLT CTVSGFSLSS YAMIWVRQAP GKGLEWIGII YAIGIKYYAN 60 WAKGRFTISK TSTTVDLKIT SPTTEDTATY FCARGDLWGP GTLVTVSSGQ PKAPSVFPLA 120 PCCGDTPSST VTLGCLVKGY LPEPVTVTWN SGTLTNGVRT FPSVRQSSGL YSLSSVVSVT 180 SSSQPVTCNV AHPATNTKVD KTVAPSTCSK PTCPPPELLG GPSVFIFPPK PKDTLMISRT 240 PEVTCVVVDV SQDDPEVQFT WYINNEQVRT ARPPLREQQF NSTIRVVSTL PIAHQDWLRG 300

224 30124-WO-PCT KEFKCKVHNK ALPAPIEKTI SKARGQPLEP KVYTMGPPRE ELSSRSVSLT CMINGFYPSD 360 ISVEWEKNGK AEDNYKTTPA VLDSDGSYFL YSKLSVPTSE WQRGDVFTCS VMHEALHNHY 420 TQKSISRSPG K 431 Sequence Number (ID): 27 Length: 447 Molecule Type: AA Features Location/Qualifiers: - source, 1..447 > mol_type, protein > organism, synthetic construct - REGION, 431..436 > note, GGGGS-linker - REGION, 437..447 > note, HiBiT sequence Residues: QSVEESGGRL VTPGTPLTLT CTVSGFSLSS YAMIWVRQAP GKGLEWIGII YAIGIKYYAN 60 WAKGRFTISK TSTTVDLKIT SPTTEDTATY FCARGDLWGP GTLVTVSSGQ PKAPSVFPLA 120 PCCGDTPSST VTLGCLVKGY LPEPVTVTWN SGTLTNGVRT FPSVRQSSGL YSLSSVVSVT 180 SSSQPVTCNV AHPATNTKVD KTVAPSTCSK PTCPPPELLG GPSVFIFPPK PKDTLMISRT 240 PEVTCVVVDV SQDDPEVQFT WYINNEQVRT ARPPLREQQF NSTIRVVSTL PIAHQDWLRG 300 KEFKCKVHNK ALPAPIEKTI SKARGQPLEP KVYTMGPPRE ELSSRSVSLT CMINGFYPSD 360 ISVEWEKNGK AEDNYKTTPA VLDSDGSYFL YSKLSVPTSE WQRGDVFTCS VMHEALHNHY 420 TQKSISRSPG KGGGGSVSGW RLFKKIS 447 Sequence Number (ID): 28 Length: 235 Molecule Type: AA Features Location/Qualifiers: - source, 1..235 > mol_type, protein > organism, synthetic construct - SIGNAL, 1..19 > note, Signal peptide Residues: MGSTAILGLL LAVLQGGRAQ VLTQTASPVS AAVGGTVTIN CQASQSLYNN KNLAWYQQKP 60 GQPPKLLIYY TATLASGVSS RFEGSGSGTH FTLTISGVQC DDAATYYCQG EFTCESADCY 120 TFGGGTEVLV KGDPVAPTVL IFPPAADQVA TGTVTIVCVA NKYFPDVTVT WEVDGTTQTT 180

225 30124-WO-PCT GIENSKTPQN SADCTYNLSS TLTLTSTQYN SHKEYTCKVT QGTTSVVQSF NRGDC 235 Sequence Number (ID): 29 Length: 450 Molecule Type: AA Features Location/Qualifiers: - source, 1..450 > mol_type, protein > organism, synthetic construct - SIGNAL, 1..19 > note, Signal peptide Residues: MGSTAILGLL LAVLQGGRAQ SVEESGGRLV TPGTPLTLTC TVSGFSLSSY AMIWVRQAPG 60 KGLEWIGIIY AIGIKYYANW AKGRFTISKT STTVDLKITS PTTEDTATYF CARGDLWGPG 120 TLVTVSSGQP KAPSVFPLAP CCGDTPSSTV TLGCLVKGYL PEPVTVTWNS GTLTNGVRTF 180 PSVRQSSGLY SLSSVVSVTS SSQPVTCNVA HPATNTKVDK TVAPSTCSKP TCPPPELLGG 240 PSVFIFPPKP KDTLMISRTP EVTCVVVDVS QDDPEVQFTW YINNEQVRTA RPPLREQQFN 300 STIRVVSTLP IAHQDWLRGK EFKCKVHNKA LPAPIEKTIS KARGQPLEPK VYTMGPPREE 360 LSSRSVSLTC MINGFYPSDI SVEWEKNGKA EDNYKTTPAV LDSDGSYFLY SKLSVPTSEW 420 QRGDVFTCSV MHEALHNHYT QKSISRSPGK 450 Sequence Number (ID): 30 Length: 466 Molecule Type: AA Features Location/Qualifiers: - source, 1..466 > mol_type, protein > organism, synthetic construct - SIGNAL, 1..19 > note, Signal peptide - REGION, 456..466 > note, HiBiT - REGION, 451..455 > note, GGGGS-linker Residues: MGSTAILGLL LAVLQGGRAQ SVEESGGRLV TPGTPLTLTC TVSGFSLSSY AMIWVRQAPG 60 KGLEWIGIIY AIGIKYYANW AKGRFTISKT STTVDLKITS PTTEDTATYF CARGDLWGPG 120 TLVTVSSGQP KAPSVFPLAP CCGDTPSSTV TLGCLVKGYL PEPVTVTWNS GTLTNGVRTF 180

226 30124-WO-PCT PSVRQSSGLY SLSSVVSVTS SSQPVTCNVA HPATNTKVDK TVAPSTCSKP TCPPPELLGG 240 PSVFIFPPKP KDTLMISRTP EVTCVVVDVS QDDPEVQFTW YINNEQVRTA RPPLREQQFN 300 STIRVVSTLP IAHQDWLRGK EFKCKVHNKA LPAPIEKTIS KARGQPLEPK VYTMGPPREE 360 LSSRSVSLTC MINGFYPSDI SVEWEKNGKA EDNYKTTPAV LDSDGSYFLY SKLSVPTSEW 420 QRGDVFTCSV MHEALHNHYT QKSISRSPGK GGGGSVSGWR LFKKIS 466 Sequence Number (ID): 31 Length: 414 Molecule Type: DNA Features Location/Qualifiers: - source, 1..414 > mol_type, other DNA > organism, synthetic construct - sig_peptide, 1..57 > note, Coding for signal peptide - misc_feature, 145..159 > note, Coding for HCDR1 - misc_feature, 202..249 > note, Coding for HCDR2 - misc_feature, 333..371 > note, Coding for HCDR3 Residues: atggagactg ggctgcgctg gcttctcctg gtcgctgtgt tcaaaggtgt ccagtgtcag 60 tcgctggagg agtccggggg tcgcctggtc acgcctggga cacccctgac actcacctgc 120 accgtctctg gattctccct cagtagcaat gcaattggct gggtccgcca ggctccaggg 180 aaggggctgg aatacatcgg gatcattggt gaaactggta ggacatacta cgcgacctgg 240 gcgaaaggcc gattcaccat ctccaaaacc tcgtcgacca cggtggatct gaaaatcacc 300 agtccgacaa ccgaggacac ggccacctat ttctgtgcca gaggttatcc tgatactagc 360 gttgccgact actttaatat gtggggccca ggcaccctgg tcaccgtctc ctca 414 Sequence Number (ID): 32 Length: 138 Molecule Type: AA Features Location/Qualifiers: - source, 1..138 > mol_type, protein > organism, synthetic construct - SIGNAL, 1..19

227 30124-WO-PCT > note, Signal peptide - REGION, 49..53 > note, HCDR1 SNAIG - REGION, 67..83 > note, HCDR2 IIGETGRTYYATWAKG - REGION, 115..127 > note, HCDR3 GYPDTSVADYFNM Residues: METGLRWLLL VAVFKGVQCQ SLEESGGRLV TPGTPLTLTC TVSGFSLSSN AIGWVRQAPG 60 KGLEYIGIIG ETGRTYYATW AKGRFTISKT SSTTVDLKIT SPTTEDTATY FCARGYPDTS 120 VADYFNMWGP GTLVTVSS 138 Sequence Number (ID): 33 Length: 399 Molecule Type: DNA Features Location/Qualifiers: - source, 1..399 > mol_type, other DNA > organism, synthetic construct - sig_peptide, 1..69 > note, Coding for signal peptide - misc_feature, 139..171 > note, Coding for LCDR1 - misc_feature, 217..237 > note, Coding for LCDR2 - misc_feature, 334..369 > note, Coding for LCDR3 Residues: atggacacga gggcccccac tcagctgctg gggctcctgc tgctctggct cccaggtgcc 60 acatttgccc aaattgatat gacccagact ccatcgtccg tgtctgaacc tgtgggaggc 120 acagtcacca tcaattgcca ggccagtcag agtattaata gttggttatc ctggtatcag 180 cagaaaccag ggcagcctcc caagctcctg atctattatg catccactct ggcatctggg 240 gtctcatcgc ggttcaaagg cagtggatct gggacacagt tcactctcac catcagcggc 300 gtgcagtgtg acgatgctgc cacttactac tgtcagcagg cttatagtta tagtgaggct 360 atcaatactt tcggcggagg gaccgaggtg gtggtcaaa 399 Sequence Number (ID): 34 Length: 133

228 30124-WO-PCT Molecule Type: AA Features Location/Qualifiers: - source, 1..133 > mol_type, protein > organism, synthetic construct - SIGNAL, 1..23 > note, Signal peptide - REGION, 47..57 > note, LCDR1 QASQSINSWLS - REGION, 73..79 > note, LCDR2 YASTLAS - REGION, 112..123 > note, QQAYSYSEAINT Residues: MDTRAPTQLL GLLLLWLPGA TFAQIDMTQT PSSVSEPVGG TVTINCQASQ SINSWLSWYQ 60 QKPGQPPKLL IYYASTLASG VSSRFKGSGS GTQFTLTISG VQCDDAATYY CQQAYSYSEA 120 INTFGGGTEV VVK 133 Sequence Number (ID): 35 Length: 166 Molecule Type: AA Features Location/Qualifiers: - source, 1..166 > mol_type, protein > organism, synthetic construct Residues: EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLI LENCKQANKH MLWKWVSNHG 60 LFNIGGSGCL GLNFSAPEOP LSLYECDSTL VSIRWRCNRK MITGPLOYSV OVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GNGGGGSLPE TGGGGG 166 Sequence Number (ID): 36 Length: 235 Molecule Type: AA Features Location/Qualifiers: - source, 1..235 > mol_type, protein > organism, synthetic construct - SIGNAL, 1..19

229 30124-WO-PCT > note, Signal number Residues: MGWSCIILFL VATATGVHSQ VLTQTASPVS AAVGGTVTIN CQASQSLYNN KNLAWYQQKP 60 GQPPKLLIYY TATLASGVSS RFEGSGSGTH FTLTISGVQC DDAATYYCQG EFTCESADCY 120 TFGGGTEVLV KGDPVAPTVL IFPPAADQVA TGTVTIVCVA NKYFPDVTVT WEVDGTTQTT 180 GIENSKTPQN SADCTYNLSS TLTLTSTQYN SHKEYTCKVT QGTTSVVQSF NRGDC 235 Sequence Number (ID): 37 Length: 450 Molecule Type: AA Features Location/Qualifiers: - source, 1..450 > mol_type, protein > organism, synthetic construct - SIGNAL, 1..19 > note, Signal peptide Residues: MGWSCIILFL VATATGVHSQ SVEESGGRLV TPGTPLTLTC TVSGFSLSSY AMIWVRQAPG 60 KGLEWIGIIY AIGIKYYANW AKGRFTISKT STTVDLKITS PTTEDTATYF CARGDLWGPG 120 TLVTVSSGQP KAPSVFPLAP CCGDTPSSTV TLGCLVKGYL PEPVTVTWNS GTLTNGVRTF 180 PSVRQSSGLY SLSSVVSVTS SSQPVTCNVA HPATNTKVDK TVAPSTCSKP TCPPPELLGG 240 PSVFIFPPKP KDTLMISRTP EVTCVVVDVS QDDPEVQFTW YINNEQVRTA RPPLREQQFN 300 STIRVVSTLP IAHQDWLRGK EFKCKVHNKA LPAPIEKTIS KARGQPLEPK VYTMGPPREE 360 LSSRSVSLTC MINGFYPSDI SVEWEKNGKA EDNYKTTPAV LDSDGSYFLY SKLSVPTSEW 420 QRGDVFTCSV MHEALHNHYT QKSISRSPGK 450 Sequence Number (ID): 38 Length: 466 Molecule Type: AA Features Location/Qualifiers: - source, 1..466 > mol_type, protein > organism, synthetic construct - SIGNAL, 1..19 > note, Signal peptide - REGION, 456..466 > note, HiBiT - REGION, 451..455

230 30124-WO-PCT > note, GGGGS-linker Residues: MGWSCIILFL VATATGVHSQ SVEESGGRLV TPGTPLTLTC TVSGFSLSSY AMIWVRQAPG 60 KGLEWIGIIY AIGIKYYANW AKGRFTISKT STTVDLKITS PTTEDTATYF CARGDLWGPG 120 TLVTVSSGQP KAPSVFPLAP CCGDTPSSTV TLGCLVKGYL PEPVTVTWNS GTLTNGVRTF 180 PSVRQSSGLY SLSSVVSVTS SSQPVTCNVA HPATNTKVDK TVAPSTCSKP TCPPPELLGG 240 PSVFIFPPKP KDTLMISRTP EVTCVVVDVS QDDPEVQFTW YINNEQVRTA RPPLREQQFN 300 STIRVVSTLP IAHQDWLRGK EFKCKVHNKA LPAPIEKTIS KARGQPLEPK VYTMGPPREE 360 LSSRSVSLTC MINGFYPSDI SVEWEKNGKA EDNYKTTPAV LDSDGSYFLY SKLSVPTSEW 420 QRGDVFTCSV MHEALHNHYT QKSISRSPGK GGGGSVSGWR LFKKIS 466 Sequence Number (ID): 39 Length: 231 Molecule Type: AA Features Location/Qualifiers: - source, 1..231 > mol_type, protein > organism, synthetic construct - SIGNAL, 1..15 > note, Signal peptide Residues: MNLLLILTFV AAAVAQVLTQ TASPVSAAVG GTVTINCQAS QSLYNNKNLA WYQQKPGQPP 60 KLLIYYTATL ASGVSSRFEG SGSGTHFTLT ISGVQCDDAA TYYCQGEFTC ESADCYTFGG 120 GTEVLVKGDP VAPTVLIFPP AADQVATGTV TIVCVANKYF PDVTVTWEVD GTTQTTGIEN 180 SKTPQNSADC TYNLSSTLTL TSTQYNSHKE YTCKVTQGTT SVVQSFNRGD C 231 Sequence Number (ID): 40 Length: 446 Molecule Type: AA Features Location/Qualifiers: - source, 1..446 > mol_type, protein > organism, synthetic construct - SIGNAL, 1..15 > note, Signal peptide Residues: MNLLLILTFV AAAVAQSVEE SGGRLVTPGT PLTLTCTVSG FSLSSYAMIW VRQAPGKGLE 60 WIGIIYAIGI KYYANWAKGR FTISKTSTTV DLKITSPTTE DTATYFCARG DLWGPGTLVT 120

231 30124-WO-PCT VSSGQPKAPS VFPLAPCCGD TPSSTVTLGC LVKGYLPEPV TVTWNSGTLT NGVRTFPSVR 180 QSSGLYSLSS VVSVTSSSQP VTCNVAHPAT NTKVDKTVAP STCSKPTCPP PELLGGPSVF 240 IFPPKPKDTL MISRTPEVTC VVVDVSQDDP EVQFTWYINN EQVRTARPPL REQQFNSTIR 300 VVSTLPIAHQ DWLRGKEFKC KVHNKALPAP IEKTISKARG QPLEPKVYTM GPPREELSSR 360 SVSLTCMING FYPSDISVEW EKNGKAEDNY KTTPAVLDSD GSYFLYSKLS VPTSEWQRGD 420 VFTCSVMHEA LHNHYTQKSI SRSPGK 446 Sequence Number (ID): 41 Length: 462 Molecule Type: AA Features Location/Qualifiers: - source, 1..462 > mol_type, protein > organism, synthetic construct - SIGNAL, 1..15 > note, Signal peptide - REGION, 452..462 > note, HiBiT VSGWRLFKKIS - REGION, 447..451 > note, GGGGS-linker Residues: MNLLLILTFV AAAVAQSVEE SGGRLVTPGT PLTLTCTVSG FSLSSYAMIW VRQAPGKGLE 60 WIGIIYAIGI KYYANWAKGR FTISKTSTTV DLKITSPTTE DTATYFCARG DLWGPGTLVT 120 VSSGQPKAPS VFPLAPCCGD TPSSTVTLGC LVKGYLPEPV TVTWNSGTLT NGVRTFPSVR 180 QSSGLYSLSS VVSVTSSSQP VTCNVAHPAT NTKVDKTVAP STCSKPTCPP PELLGGPSVF 240 IFPPKPKDTL MISRTPEVTC VVVDVSQDDP EVQFTWYINN EQVRTARPPL REQQFNSTIR 300 VVSTLPIAHQ DWLRGKEFKC KVHNKALPAP IEKTISKARG QPLEPKVYTM GPPREELSSR 360 SVSLTCMING FYPSDISVEW EKNGKAEDNY KTTPAVLDSD GSYFLYSKLS VPTSEWQRGD 420 VFTCSVMHEA LHNHYTQKSI SRSPGKGGGG SVSGWRLFKK IS 462 Sequence Number (ID): 42 Length: 347 Molecule Type: AA Features Location/Qualifiers: - source, 1..347 > mol_type, protein > organism, synthetic construct Residues:

232 30124-WO-PCT EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60 LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GNTHGMPCMF PFQYNHQWHH ECTREGREDD 180 LLWCATTSRY ERDEKWGFCP DPTSAEVGCD TIWEKDLNSH ICYQFNLLSS LSWSEAHSSC 240 QMQGGTLLSI TDETEENFIR EHMSSKTVEV WMGLNQLDEH AGWQWSDGTP LNYLNWSPEV 300 NFEPFVEDHC GTFSSFMPSA WRSRDCESTL PYICKKYLNH IDHEIVE 347 Sequence Number (ID): 43 Length: 104 Molecule Type: AA Features Location/Qualifiers: - source, 1..104 > mol_type, protein > organism, Oryctolagus cuniculus Residues: GDPVAPTVLI FPPAADQVAT GTVTIVCVAN KYFPDVTVTW EVDGTTQTTG IENSKTPQNS 60 ADCTYNLSST LTLTSTQYNS HKEYTCKVTQ GTTSVVQSFN RGDC 104 Sequence Number (ID): 44 Length: 323 Molecule Type: AA Features Location/Qualifiers: - source, 1..323 > mol_type, protein > organism, Oryctolagus cuniculus Residues: GQPKAPSVFP LAPCCGDTPS STVTLGCLVK GYLPEPVTVT WNSGTLTNGV RTFPSVRQSS 60 GLYSLSSVVS VTSSSQPVTC NVAHPATNTK VDKTVAPSTC SKPTCPPPEL LGGPSVFIFP 120 PKPKDTLMIS RTPEVTCVVV DVSQDDPEVQ FTWYINNEQV RTARPPLREQ QFNSTIRVVS 180 TLPITHQDWL RGKEFKCKVH NKALPAPIEK TISKARGQPL EPKVYTMGPP REELSSRSVS 240 LTCMINGFYP SDISVEWEKN GKAEDNYKTT PAVLDSDGSY FLYNKLSVPT SEWQRGDVFT 300 CSVMHEALHN HYTQKSISRS PGK 323 Sequence Number (ID): 45 Length: 214 Molecule Type: AA Features Location/Qualifiers: - source, 1..214

233 30124-WO-PCT > mol_type, protein > organism, synthetic construct Residues: QIDMTQTPSS VSEPVGGTVT INCQASQSIN SWLSWYQQKP GQPPKLLIYY ASTLASGVSS 60 RFKGSGSGTQ FTLTISGVQC DDAATYYCQQ AYSYSEAINT FGGGTEVVVK GDPVAPTVLI 120 FPPAADQVAT GTVTIVCVAN KYFPDVTVTW EVDGTTQTTG IENSKTPQNS ADCTYNLSST 180 LTLTSTQYNS HKEYTCKVTQ GTTSVVQSFN RGDC 214 Sequence Number (ID): 46 Length: 442 Molecule Type: AA Features Location/Qualifiers: - source, 1..442 > mol_type, protein > organism, synthetic construct Residues: QSLEESGGRL VTPGTPLTLT CTVSGFSLSS NAIGWVRQAP GKGLEYIGII GETGRTYYAT 60 WAKGRFTISK TSSTTVDLKI TSPTTEDTAT YFCARGYPDT SVADYFNMWG PGTLVTVSSG 120 QPKAPSVFPL APCCGDTPSS TVTLGCLVKG YLPEPVTVTW NSGTLTNGVR TFPSVRQSSG 180 LYSLSSVVSV TSSSQPVTCN VAHPATNTKV DKTVAPSTCS KPTCPPPELL GGPSVFIFPP 240 KPKDTLMISR TPEVTCVVVD VSQDDPEVQF TWYINNEQVR TARPPLREQQ FNSTIRVVST 300 LPITHQDWLR GKEFKCKVHN KALPAPIEKT ISKARGQPLE PKVYTMGPPR EELSSRSVSL 360 TCMINGFYPS DISVEWEKNG KAEDNYKTTP AVLDSDGSYF LYNKLSVPTS EWQRGDVFTC 420 SVMHEALHNH YTQKSISRSP GK 442 Sequence Number (ID): 47 Length: 217 Molecule Type: AA Features Location/Qualifiers: - source, 1..217 > mol_type, protein > organism, synthetic construct Residues: AQVLTQTPSP VSAAVGGTVT INCQASQSVY NNENLAWYQQ KLGQPPKLLI YDASTLASGV 60 PLRFSASGSG TQFTLTISDV QCDDAATYYC QGEFSCDSAD CNVFGGGTEV VVKGDPVAPT 120 VLIFPPAADQ VATGTVTIVC VANKYFPDVT VTWEVDGTTQ TTGIENSKTP QNSADCTYNL 180 SSTLTLTSTQ YNSHKEYTCK VTQGTTSVVQ SFNRGDC 217

234 30124-WO-PCT Sequence Number (ID): 48 Length: 438 Molecule Type: AA Features Location/Qualifiers: - source, 1..438 > mol_type, protein > organism, synthetic construct Residues: QSVEESGGRL VTPGTPLTLT CTVSGFSLST YAMNWVRQAP GKGLEWIGVI SAGGTTFYTS 60 WAKGRFTISR TSTTVDLKIT SPTTEDTATY FCVRKNYSIR SFDIWGPGTL VTVSSGQPKA 120 PSVFPLAPCC GDTPSSTVTL GCLVKGYLPE PVTVTWNSGT LTNGVRTFPS VRQSSGLYSL 180 SSVVSVTSSS QPVTCNVAHP ATNTKVDKTV APSTCSKPTC PPPELLGGPS VFIFPPKPKD 240 TLMISRTPEV TCVVVDVSQD DPEVQFTWYI NNEQVRTARP PLREQQFNST IRVVSTLPIT 300 HQDWLRGKEF KCKVHNKALP APIEKTISKA RGQPLEPKVY TMGPPREELS SRSVSLTCMI 360 NGFYPSDISV EWEKNGKAED NYKTTPAVLD SDGSYFLYNK LSVPTSEWQR GDVFTCSVMH 420 EALHNHYTQK SISRSPGK 438 Sequence Number (ID): 49 Length: 217 Molecule Type: AA Features Location/Qualifiers: - source, 1..217 > mol_type, protein > organism, synthetic construct Residues: AQVLTQTPSP VSAAVGGTVT INCQASQSVY NNENLAWYQQ KPGQPPKLLI YDASTLASGV 60 PSRFSGSGSG TQFTLTISGV QCEDAATYYC QGEFDCNSAD CHVFGGGTEV VVKGDPVAPT 120 VLIFPPAADQ VATGTVTIVC VANKYFPDVT VTWEVDGTTQ TTGIENSKTP QNSADCTYNL 180 SSTLTLTSTQ YNSHKEYTCK VTQGTTSVVQ SFNRGDC 217 Sequence Number (ID): 50 Length: 438 Molecule Type: AA Features Location/Qualifiers: - source, 1..438 > mol_type, protein > organism, synthetic construct Residues:

235 30124-WO-PCT QSMEESGGRL VTPGTPLTLT CTVSGFSLSS FQMNWVRQTP GKGLEWIGGI SAGGSVFYAN 60 WAKGRFTISR TSTTLDLQIT SPTTEDTATY FCARKSYNIA GLDNWGPGTL VTVSSGQPKA 120 PSVFPLAPCC GDTPSSTVTL GCLVKGYLPE PVTVTWNSGT LTNGVRTFPS VRQSSGLYSL 180 SSVVSVTSSS QPVTCNVAHP ATNTKVDKTV APSTCSKPTC PPPELLGGPS VFIFPPKPKD 240 TLMISRTPEV TCVVVDVSQD DPEVQFTWYI NNEQVRTARP PLREQQFNST IRVVSTLPIT 300 HQDWLRGKEF KCKVHNKALP APIEKTISKA RGQPLEPKVY TMGPPREELS SRSVSLTCMI 360 NGFYPSDISV EWEKNGKAED NYKTTPAVLD SDGSYFLYNK LSVPTSEWQR GDVFTCSVMH 420 EALHNHYTQK SISRSPGK 438 Sequence Number (ID): 51 Length: 214 Molecule Type: AA Features Location/Qualifiers: - source, 1..214 > mol_type, protein > organism, synthetic construct Residues: EVVMTQTPSS VSGAVGGTVT IKCQASEDIG RLLAWYQQKP GQPPKLLIYG TSILESGVPS 60 RFKGSGAGTQ FTLTISDLEC ADAATYYCQA TYGSSTNGNS FGGGTEVVVK GDPVAPTVLI 120 FPPAADQVAT GTVTIVCVAN KYFPDVTVTW EVDGTTQTTG IENSKTPQNS ADCTYNLSST 180 LTLTSTQYNS HKEYTCKVTQ GTTSVVQSFN RGDC 214 Sequence Number (ID): 52 Length: 435 Molecule Type: AA Features Location/Qualifiers: - source, 1..435 > mol_type, protein > organism, synthetic construct Residues: QSVEESGGRL VMPGTPLTLT CTVSGFSLSR YNMAWVRQAP GKGLEYIGII SYSNNTYYAN 60 WAKGRFTISK TSSTTVDLKM TSLTTEDTAT YFCARGVGTN IWGPGTLVTV SSGQPKAPSV 120 FPLAPCCGDT PSSTVTLGCL VKGYLPEPVT VTWNSGTLTN GVRTFPSVRQ SSGLYSLSSV 180 VSVTSSSQPV TCNVAHPATN TKVDKTVAPS TCSKPTCPPP ELLGGPSVFI FPPKPKDTLM 240 ISRTPEVTCV VVDVSQDDPE VQFTWYINNE QVRTARPPLR EQQFNSTIRV VSTLPITHQD 300 WLRGKEFKCK VHNKALPAPI EKTISKARGQ PLEPKVYTMG PPREELSSRS VSLTCMINGF 360 YPSDISVEWE KNGKAEDNYK TTPAVLDSDG SYFLYNKLSV PTSEWQRGDV FTCSVMHEAL 420 HNHYTQKSIS RSPGK 435

236 30124-WO-PCT Sequence Number (ID): 53 Length: 363 Molecule Type: AA Features Location/Qualifiers: - source, 1..363 > mol_type, protein > organism, synthetic construct - REGION, 354..363 > note, His10 - REGION, 348..353 > note, Thrombin recognition sequence LVPRGS Residues: EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60 LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GNTHGMPCMF PFQYNHQWHH ECTREGREDD 180 LLWCATTSRY ERDEKWGFCP DPTSAEVGCD TIWEKDLNSH ICYQFNLLSS LSWSEAHSSC 240 QMQGGTLLSI TDETEENFIR EHMSSKTVEV WMGLNQLDEH AGWQWSDGTP LNYLNWSPEV 300 NFEPFVEDHC GTFSSFMPSA WRSRDCESTL PYICKKYLNH IDHEIVELVP RGSHHHHHHH 360 HHH 363 Sequence Number (ID): 54 Length: 158 Molecule Type: AA Features Location/Qualifiers: - source, 1..158 > mol_type, protein > organism, synthetic construct - REGION, 149..158 > note, His10 - REGION, 134..147 > note, Avi tag GLNDIFEAQKIEWHE - REGION, 128..133 > note, GGSGGS linker Residues: NTSDMYPMPN TLEYGNRTYK IINANMTWYA AIKTCLMHKA QLVSITDQYH QSFLTVVLNR 60 LGYAHWIGLF TTDNGLNFDW SDGTKSSFTF WKDEESSLLG DCVFADSNGR WHSTACESFL 120 QGAICHVGGS GGSGLNDIFE AQKIEWHEHH HHHHHHHH 158

237 30124-WO-PCT Sequence Number (ID): 55 Length: 1258 Molecule Type: AA Features Location/Qualifiers: - source, 1..1258 > mol_type, protein > organism, synthetic construct - REGION, 1249..1258 > note, His10 - REGION, 1244..1258 > note, Avi tag GLNDIFEAQKIEWHE - REGION, 1238..1243 > note, GGSGGS linker Residues: GNTHGMPCMF PFQYNHQWHH ECTREGREDD LLWCATTSRY ERDEKWGFCP DPTSAEVGCD 60 TIWEKDLNSH ICYQFNLLSS LSWSEAHSSC QMQGGTLLSI TDETEENFIR EHMSSKTVEV 120 WMGLNQLDEH AGWQWSDGTP LNYLNWSPEV NFEPFVEDHC GTFSSFMPSA WRSRDCESTL 180 PYICKKYLNH IDHEIVEKDA WKYYATHCEP GWNPYNRNCY KLQKEEKTWH EALRSCQADN 240 SALIDITSLA EVEFLVTLLG DENASETWIG LSSNKIPVSF EWSNDSSVIF TNWHTLEPHI 300 FPNRSQLCVS AEQSEGHWKV KNCEERLFYI CKKAGHVLSD AESGCQEGWE RHGGFCYKID 360 TVLRSFDQAS SGYYCPPALV TITNRFEQAF ITSLISSVVK MKDSYFWIAL QDQNDTGEYT 420 WKPVGQKPEP VQYTHWNTHQ PRYSGGCVAM RGRHPLGRWE VKHCRHFKAM SLCKQPVENQ 480 EKAEYEERWP FHPCYLDWES EPGLASCFKV FHSEKVLMKR TWREAEAFCE EFGAHLASFA 540 HIEEENFVNE LLHSKFNWTE ERQFWIGFNK RNPLNAGSWE WSDRTPVVSS FLDNTYFGED 600 ARNCAVYKAN KTLLPLHCGS KREWICKIPR DVKPKIPFWY QYDVPWLFYQ DAEYLFHTFA 660 SEWLNFEFVC SWLHSDLLTI HSAHEQEFIH SKIKALSKYG ASWWIGLQEE RANDEFRWRD 720 GTPVIYQNWD TGRERTVNNQ SQRCGFISSI TGLWGSEECS VSMPSICKRK KVWLIEKKKD 780 TPKQHGTCPK GWLYFNYKCL LLNIPKDPSS WKNWTHAQHF CAEEGGTLVA IESEVEQAFI 840 TMNLFGQTTS VWIGLQNDDY ETWLNGKPVV YSNWSPFDII NIPSHNTTEV QKHIPLCALL 900 SSNPNFHFTG KWYFEDCGKE GYGFVCEKMQ DTSGHGVNTS DMYPMPNTLE YGNRTYKIIN 960 ANMTWYAAIK TCLMHKAQLV SITDQYHQSF LTVVLNRLGY AHWIGLFTTD NGLNFDWSDG 1020 TKSSFTFWKD EESSLLGDCV FADSNGRWHS TACESFLQGA ICHVPPETRQ SEHPELCSET 1080 SIPWIKFKSN CYSFSTVLDS MSFEAAHEFC KKEGSNLLTI KDEAENAFLL EELFAFGSSV 1140 QMVWLNAQFD GNNETIKWFD GTPTDQSNWG IRKPDTDYFK PHHCVALRIP EGLWQLSPCQ 1200 EKKGFICKME ADIHTAEALP EKGPSHSGGS GGSGLNDIFE AQKIEWHEHH HHHHHHHH 1258 Sequence Number (ID): 56

238 30124-WO-PCT Length: 1408 Molecule Type: AA Features Location/Qualifiers: - source, 1..1408 > mol_type, protein > organism, synthetic construct - REGION, 1399..1408 > note, His10 - REGION, 1324..1398 > note, Avi tag GLNDIFEAQKIEWHE - REGION, 1318..1323 > note, GGSGGS linker - REGION, 136..141 > note, Thrombin cleavage site engineered between CysR and FnII domains LVPRGS Residues: EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60 LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLVPRG SNTHGMPCMF PFQYNHQWHH ECTREGREDD 180 LLWCATTSRY ERDEKWGFCP DPTSAEVGCD TIWEKDLNSH ICYQFNLLSS LSWSEAHSSC 240 QMQGGTLLSI TDETEENFIR EHMSSKTVEV WMGLNQLDEH AGWQWSDGTP LNYLNWSPEV 300 NFEPFVEDHC GTFSSFMPSA WRSRDCESTL PYICKKYLNH IDHEIVEKDA WKYYATHCEP 360 GWNPYNRNCY KLQKEEKTWH EALRSCQADN SALIDITSLA EVEFLVTLLG DENASETWIG 420 LSSNKIPVSF EWSNDSSVIF TNWHTLEPHI FPNRSQLCVS AEQSEGHWKV KNCEERLFYI 480 CKKAGHVLSD AESGCQEGWE RHGGFCYKID TVLRSFDQAS SGYYCPPALV TITNRFEQAF 540 ITSLISSVVK MKDSYFWIAL QDQNDTGEYT WKPVGQKPEP VQYTHWNTHQ PRYSGGCVAM 600 RGRHPLGRWE VKHCRHFKAM SLCKQPVENQ EKAEYEERWP FHPCYLDWES EPGLASCFKV 660 FHSEKVLMKR TWREAEAFCE EFGAHLASFA HIEEENFVNE LLHSKFNWTE ERQFWIGFNK 720 RNPLNAGSWE WSDRTPVVSS FLDNTYFGED ARNCAVYKAN KTLLPLHCGS KREWICKIPR 780 DVKPKIPFWY QYDVPWLFYQ DAEYLFHTFA SEWLNFEFVC SWLHSDLLTI HSAHEQEFIH 840 SKIKALSKYG ASWWIGLQEE RANDEFRWRD GTPVIYQNWD TGRERTVNNQ SQRCGFISSI 900 TGLWGSEECS VSMPSICKRK KVWLIEKKKD TPKQHGTCPK GWLYFNYKCL LLNIPKDPSS 960 WKNWTHAQHF CAEEGGTLVA IESEVEQAFI TMNLFGQTTS VWIGLQNDDY ETWLNGKPVV 1020 YSNWSPFDII NIPSHNTTEV QKHIPLCALL SSNPNFHFTG KWYFEDCGKE GYGFVCEKMQ 1080 DTSGHGVNTS DMYPMPNTLE YGNRTYKIIN ANMTWYAAIK TCLMHKAQLV SITDQYHQSF 1140 LTVVLNRLGY AHWIGLFTTD NGLNFDWSDG TKSSFTFWKD EESSLLGDCV FADSNGRWHS 1200 TACESFLQGA ICHVPPETRQ SEHPELCSET SIPWIKFKSN CYSFSTVLDS MSFEAAHEFC 1260 KKEGSNLLTI KDEAENAFLL EELFAFGSSV QMVWLNAQFD GNNETIKWFD GTPTDQSNWG 1320

239 30124-WO-PCT IRKPDTDYFK PHHCVALRIP EGLWQLSPCQ EKKGFICKME ADIHTAEALP EKGPSHSGGS 1380 GGSGLNDIFE AQKIEWHEHH HHHHHHHH 1408 Sequence Number (ID): 57 Length: 1060 Molecule Type: AA Features Location/Qualifiers: - source, 1..1060 > mol_type, protein > organism, synthetic construct - REGION, 1051..1060 > note, His10 - REGION, 1036..1050 > note, Avi tag GLNDIFEAQKIEWHE - REGION, 1030..1035 > note, GGSGGS linker Residues: DAWKYYATHC EPGWNPYNRN CYKLQKEEKT WHEALRSCQA DNSALIDITS LAEVEFLVTL 60 LGDENASETW IGLSSNKIPV SFEWSNDSSV IFTNWHTLEP HIFPNRSQLC VSAEQSEGHW 120 KVKNCEERLF YICKKAGHVL SDAESGCQEG WERHGGFCYK IDTVLRSFDQ ASSGYYCPPA 180 LVTITNRFEQ AFITSLISSV VKMKDSYFWI ALQDQNDTGE YTWKPVGQKP EPVQYTHWNT 240 HQPRYSGGCV AMRGRHPLGR WEVKHCRHFK AMSLCKQPVE NQEKAEYEER WPFHPCYLDW 300 ESEPGLASCF KVFHSEKVLM KRTWREAEAF CEEFGAHLAS FAHIEEENFV NELLHSKFNW 360 TEERQFWIGF NKRNPLNAGS WEWSDRTPVV SSFLDNTYFG EDARNCAVYK ANKTLLPLHC 420 GSKREWICKI PRDVKPKIPF WYQYDVPWLF YQDAEYLFHT FASEWLNFEF VCSWLHSDLL 480 TIHSAHEQEF IHSKIKALSK YGASWWIGLQ EERANDEFRW RDGTPVIYQN WDTGRERTVN 540 NQSQRCGFIS SITGLWGSEE CSVSMPSICK RKKVWLIEKK KDTPKQHGTC PKGWLYFNYK 600 CLLLNIPKDP SSWKNWTHAQ HFCAEEGGTL VAIESEVEQA FITMNLFGQT TSVWIGLQND 660 DYETWLNGKP VVYSNWSPFD IINIPSHNTT EVQKHIPLCA LLSSNPNFHF TGKWYFEDCG 720 KEGYGFVCEK MQDTSGHGVN TSDMYPMPNT LEYGNRTYKI INANMTWYAA IKTCLMHKAQ 780 LVSITDQYHQ SFLTVVLNRL GYAHWIGLFT TDNGLNFDWS DGTKSSFTFW KDEESSLLGD 840 CVFADSNGRW HSTACESFLQ GAICHVPPET RQSEHPELCS ETSIPWIKFK SNCYSFSTVL 900 DSMSFEAAHE FCKKEGSNLL TIKDEAENAF LLEELFAFGS SVQMVWLNAQ FDGNNETIKW 960 FDGTPTDQSN WGIRKPDTDY FKPHHCVALR IPEGLWQLSP CQEKKGFICK MEADIHTAEA 1020 LPEKGPSHSG GSGGSGLNDI FEAQKIEWHE HHHHHHHHHH 1060 Sequence Number (ID): 58 Length: 1408

240 30124-WO-PCT Molecule Type: AA Features Location/Qualifiers: - source, > mol_type, protein > organism, synthetic construct - REGION, 1399..1408 > note, His6 - REGION, 1384..1398 Avi tag GLNDIFEAQKIEWHE - REGION, 1378..1383 > GGSGGS linker - REGION, 325..330 Thrombin cleavage site engineered between CTDL1 and CTDL2 domains LVPRGS EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60 LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GNTHGMPCMF PFQYNHQWHH ECTREGREDD 180 LLWCATTSRY ERDEKWGFCP DPTSAEVGCD TIWEKDLNSH ICYQFNLLSS LSWSEAHSSC 240 QMQGGTLLSI TDETEENFIR EHMSSKTVEV WMGLNQLDEH AGWQWSDGTP LNYLNWSPEV 300 NFEPFVEDHC GTFSSFMPSA WRSRDCESTL PYICKKYLNH IDHELVPRGS WKYYATHCEP 360 GWNPYNRNCY KLQKEEKTWH EALRSCQADN SALIDITSLA EVEFLVTLLG DENASETWIG 420 LSSNKIPVSF EWSNDSSVIF TNWHTLEPHI FPNRSQLCVS AEQSEGHWKV KNCEERLFYI 480 CKKAGHVLSD AESGCQEGWE RHGGFCYKID TVLRSFDQAS SGYYCPPALV TITNRFEQAF 540 ITSLISSVVK MKDSYFWIAL QDQNDTGEYT WKPVGQKPEP VQYTHWNTHQ PRYSGGCVAM 600 RGRHPLGRWE VKHCRHFKAM SLCKQPVENQ EKAEYEERWP FHPCYLDWES EPGLASCFKV 660 FHSEKVLMKR TWREAEAFCE EFGAHLASFA HIEEENFVNE LLHSKFNWTE ERQFWIGFNK 720 RNPLNAGSWE WSDRTPVVSS FLDNTYFGED ARNCAVYKAN KTLLPLHCGS KREWICKIPR 780 DVKPKIPFWY QYDVPWLFYQ DAEYLFHTFA SEWLNFEFVC SWLHSDLLTI HSAHEQEFIH 840 SKIKALSKYG ASWWIGLQEE RANDEFRWRD GTPVIYQNWD TGRERTVNNQ SQRCGFISSI 900 TGLWGSEECS VSMPSICKRK KVWLIEKKKD TPKQHGTCPK GWLYFNYKCL LLNIPKDPSS 960 WKNWTHAQHF CAEEGGTLVA IESEVEQAFI TMNLFGQTTS VWIGLQNDDY ETWLNGKPVV 1020 YSNWSPFDII NIPSHNTTEV QKHIPLCALL SSNPNFHFTG KWYFEDCGKE GYGFVCEKMQ 1080 DTSGHGVNTS DMYPMPNTLE YGNRTYKIIN ANMTWYAAIK TCLMHKAQLV SITDQYHQSF 1140 LTVVLNRLGY AHWIGLFTTD NGLNFDWSDG TKSSFTFWKD EESSLLGDCV FADSNGRWHS 1200 TACESFLQGA ICHVPPETRQ SEHPELCSET SIPWIKFKSN CYSFSTVLDS MSFEAAHEFC 1260 KKEGSNLLTI KDEAENAFLL EELFAFGSSV QMVWLNAQFD GNNETIKWFD GTPTDQSNWG 1320 IRKPDTDYFK PHHCVALRIP EGLWQLSPCQ EKKGFICKME ADIHTAEALP EKGPSHSGGS 1380

241 30124-WO-PCT GGSGLNDIFE AQKIEWHEHH HHHHHHHH 1408 Sequence Number (ID): 59 Length: 364 Molecule Type: AA Features Location/Qualifiers: - source, 1..364 > mol_type, protein > organism, synthetic construct - MOD_RES, 364 > note, GN3 conjugated to the C-terminal cysteine residue via maleimide conjugation Residues: EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60 LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GNTHGMPCMF PFQYNHQWHH ECTREGREDD 180 LLWCATTSRY ERDEKWGFCP DPTSAEVGCD TIWEKDLNSH ICYQFNLLSS LSWSEAHSSC 240 QMQGGTLLSI TDETEENFIR EHMSSKTVEV WMGLNQLDEH AGWQWSDGTP LNYLNWSPEV 300 NFEPFVEDHC GTFSSFMPSA WRSRDCESTL PYICKKYLNH IDHEIVEGGG GSHHHHHHGG 360 GGSC 364 Sequence Number (ID): 60 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: AEQSEGHWKV KNCEE 15 Sequence Number (ID): 61 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens

242 30124-WO-PCT Residues: AESGCQEGWE RHGGF 15 Sequence Number (ID): 62 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: AHEFCKKEGS NLLTI 15 Sequence Number (ID): 63 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: AHSSCQMQGG TLLSI 15 Sequence Number (ID): 64 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: ARNCAVYKAN KTLLP 15 Sequence Number (ID): 65 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15

243 30124-WO-PCT > mol_type, protein > organism, Homo sapiens Residues: CAEEGGTLVA IESEV 15 Sequence Number (ID): 66 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: CEKMQDTSGH GVNTS 15 Sequence Number (ID): 67 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: CESTLPYICK KYLNH 15 Sequence Number (ID): 68 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: CIQAGKSVLT LENCK 15 Sequence Number (ID): 69 Length: 15 Molecule Type: AA

244 30124-WO-PCT Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: CKKAGHVLSD AESGC 15 Sequence Number (ID): 70 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: CQADNSALID ITSLA 15 Sequence Number (ID): 71 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: CYKIDTVLRS FDQAS 15 Sequence Number (ID): 72 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: CYSFSTVLDS MSFEA 15 Sequence Number (ID): 73

245 30124-WO-PCT Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: DCGKEGYGFV CEKMQ 15 Sequence Number (ID): 74 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: EALRSCQADN SALID 15 Sequence Number (ID): 75 Length: 20 Molecule Type: AA Features Location/Qualifiers: - source, 1..20 > mol_type, protein > organism, Homo sapiens Residues: EALRSCQADN SALIDITSLA 20 Sequence Number (ID): 76 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: EESSLLGDCV FADSN 15

246 30124-WO-PCT Sequence Number (ID): 77 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: EGLWQLSPCQ EKKGF 15 Sequence Number (ID): 78 Length: 25 Molecule Type: AA Features Location/Qualifiers: - source, 1..25 > mol_type, protein > organism, Homo sapiens Residues: EGLWQLSPCQ EKKGFICKME ADIHT 25 Sequence Number (ID): 79 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: EKKGFICKME ADIHT 15 Sequence Number (ID): 80 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens

247 30124-WO-PCT Residues: EKTWHEALRS CQADN 15 Sequence Number (ID): 81 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: ESLKKCIQAG KSVLT 15 Sequence Number (ID): 82 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: EVGCDTIWEK DLNSH 15 Sequence Number (ID): 83 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: FADSNGRWHS TACES 15 Sequence Number (ID): 84 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15

248 30124-WO-PCT > mol_type, protein > organism, Homo sapiens Residues: FLQGAICHVP PETRQ 15 Sequence Number (ID): 85 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: FPNRSQLCVS AEQSE 15 Sequence Number (ID): 86 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: GCVAMRGRHP LGRWE 15 Sequence Number (ID): 87 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: GDICEYLHKD LHTIK 15 Sequence Number (ID): 88 Length: 13 Molecule Type: AA

249 30124-WO-PCT Features Location/Qualifiers: - source, 1..13 > mol_type, protein > organism, Homo sapiens Residues: GIFVIQSESL KKC 13 Sequence Number (ID): 89 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: GLNFSAPEQP LSLYE 15 Sequence Number (ID): 90 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: GNTHGMPCMF PFQYN 15 Sequence Number (ID): 91 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: GRWHSTACES FLQGA 15 Sequence Number (ID): 92

250 30124-WO-PCT Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: GSGCLGLNFS APEQP 15 Sequence Number (ID): 93 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: GYGFVCEKMQ DTSGH 15 Sequence Number (ID): 94 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: HAQHFCAEEG GTLVA 15 Sequence Number (ID): 95 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: HFKAMSLCKQ PVENQ 15

251 30124-WO-PCT Sequence Number (ID): 96 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: HQWHHECTRE GREDD 15 Sequence Number (ID): 97 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: HVLSDAESGC QEGWE 15 Sequence Number (ID): 98 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: ICHVPPETRQ SEHPE 15 Sequence Number (ID): 99 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens

252 30124-WO-PCT Residues: ICKMEADIHT AEALP 15 Sequence Number (ID): 100 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: KKEGSNLLTI KDEAE 15 Sequence Number (ID): 101 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: KLQKEEKTWH EALRS 15 Sequence Number (ID): 102 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: KTLLPLHCGS KREWI 15 Sequence Number (ID): 103 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15

253 30124-WO-PCT > mol_type, protein > organism, Homo sapiens Residues: KYLNHIDHEI VEKDA 15 Sequence Number (ID): 104 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: LEPHIFPNRS QLCVS 15 Sequence Number (ID): 105 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: LFNIGGSGCL GLNFS 15 Sequence Number (ID): 106 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: LGDCVFADSN GRWHS 15 Sequence Number (ID): 107 Length: 15 Molecule Type: AA

254 30124-WO-PCT Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: LHTIKGNTHG MPCMF 15 Sequence Number (ID): 108 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: LLLGAPRGCA EGVAA 15 Sequence Number (ID): 109 Length: 20 Molecule Type: AA Features Location/Qualifiers: - source, 1..20 > mol_type, protein > organism, Homo sapiens Residues: LLLGAPRGCA EGVAAALTPE 20 Sequence Number (ID): 110 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: LLWCATTSRY ERDEK 15 Sequence Number (ID): 111

255 30124-WO-PCT Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: LSPCQEKKGF ICKME 15 Sequence Number (ID): 112 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: LSWSEAHSSC QMQGG 15 Sequence Number (ID): 113 Length: 20 Molecule Type: AA Features Location/Qualifiers: - source, 1..20 > mol_type, protein > organism, Homo sapiens Residues: LSWSEAHSSC QMQGGTLLSI 20 Sequence Number (ID): 114 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: MPCMFPFQYN HQWHH 15

256 30124-WO-PCT Sequence Number (ID): 115 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: MSFEAAHEFC KKEGS 15 Sequence Number (ID): 116 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: NFEPFVEDHC GTFSS 15 Sequence Number (ID): 117 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: NGLNFDWSDG TKSSF 15 Sequence Number (ID): 118 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens

257 30124-WO-PCT Residues: NRNCYKLQKE EKTWH 15 Sequence Number (ID): 119 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: NTTEVQKHIP LCALL 15 Sequence Number (ID): 120 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: PFDIINIPSH NTTEV 15 Sequence Number (ID): 121 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: PRGCAEGVAA ALTPE 15 Sequence Number (ID): 122 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15

258 30124-WO-PCT > mol_type, protein > organism, Homo sapiens Residues: PRYSGGCVAM RGRHP 15 Sequence Number (ID): 123 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: PYICKKYLNH IDHEI 15 Sequence Number (ID): 124 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: QKHIPLCALL SSNPN 15 Sequence Number (ID): 125 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: QLCVSAEQSE GHWKV 15 Sequence Number (ID): 126 Length: 15 Molecule Type: AA

259 30124-WO-PCT Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: RCNRKMITGP LQYSV 15 Sequence Number (ID): 127 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: SEECSVSMPS ICKRK 15 Sequence Number (ID): 128 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: SLCKQPVENQ EKAEY 15 Sequence Number (ID): 129 Length: 9 Molecule Type: AA Features Location/Qualifiers: - source, 1..9 > mol_type, protein > organism, Homo sapiens Residues: SVLTLENCK 9 Sequence Number (ID): 130

260 30124-WO-PCT Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: TCLMHKAQLV SITDQ 15 Sequence Number (ID): 131 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: TGLWGSEECS VSMPS 15 Sequence Number (ID): 132 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: TKSSFTFWKD EESSL 15 Sequence Number (ID): 133 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: TLLSITDETE ENFIR 15

261 30124-WO-PCT Sequence Number (ID): 134 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: TTSRYERDEK WGFCP 15 Sequence Number (ID): 135 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: TVNNQSQRCG FISSI 15 Sequence Number (ID): 136 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: VEDHCGTFSS FMPSA 15 Sequence Number (ID): 137 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens

262 30124-WO-PCT Residues: VKHCRHFKAM SLCKQ 15 Sequence Number (ID): 138 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: VSLRWRCNRK MITGP 15 Sequence Number (ID): 139 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: VSNHGLFNIG GSGCL 15 Sequence Number (ID): 140 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: WKNWTHAQHF CAEEG 15 Sequence Number (ID): 141 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15

263 30124-WO-PCT > mol_type, protein > organism, Homo sapiens Residues: WNTHQPRYSG GCVAM 15 Sequence Number (ID): 142 Length: 31 Molecule Type: AA Features Location/Qualifiers: - source, 1..31 > mol_type, protein > organism, Homo sapiens Residues: WQDKGIFVIQ SESLKKCIQA GKSVLTLENC K 31 Sequence Number (ID): 143 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: YAAIKTCLMH KAQLV 15 Sequence Number (ID): 144 Length: 15 Molecule Type: AA Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: YFGEDARNCA VYKAN 15 Sequence Number (ID): 145 Length: 15 Molecule Type: AA

264 30124-WO-PCT Features Location/Qualifiers: - source, 1..15 > mol_type, protein > organism, Homo sapiens Residues: YLHKDLHTIK GNTHG 15 Sequence Number (ID): 146 Length: 364 Molecule Type: AA Features Location/Qualifiers: - source, 1..364 > mol_type, protein > organism, synthetic construct Residues: EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60 LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GNTHGMPCMF PFQYNHQWHH ECTREGREDD 180 LLWCATTSRY ERDEKWGFCP DPTSAEVGCD TIWEKDLNSH ICYQFNLLSS LSWSEAHSSC 240 QMQGGTLLSI TDETEENFIR EHMSSKTVEV WMGLNQLDEH AGWQWSDGTP LNYLNWSPEV 300 NFEPFVEDHC GTFSSFMPSA WRSRDCESTL PYICKKYLNH IDHEIVEGGG GSHHHHHHGG 360 GGSC 364 Sequence Number (ID): 147 Length: 359 Molecule Type: AA Features Location/Qualifiers: - source, 1..359 > mol_type, protein > organism, synthetic construct - SITE, 359 > note, Terminal Cys - REGION, 353..358 > note, His6 - REGION, 348..352 > note, GGGGS-linker Residues: EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60

265 30124-WO-PCT LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GNTHGMPCMF PFQYNHQWHH ECTREGREDD 180 LLWCATTSRY ERDEKWGFCP DPTSAEVGCD TIWEKDLNSH ICYQFNLLSS LSWSEAHSSC 240 QMQGGTLLSI TDETEENFIR EHMSSKTVEV WMGLNQLDEH AGWQWSDGTP LNYLNWSPEV 300 NFEPFVEDHC GTFSSFMPSA WRSRDCESTL PYICKKYLNH IDHEIVEGGG GSHHHHHHC 359 Sequence Number (ID): 148 Length: 364 Molecule Type: AA Features Location/Qualifiers: - source, 1..364 > mol_type, protein > organism, synthetic construct - SITE, 363 > note, Next to terminal Cys - REGION, 359..362 > note, GGGE-linker - REGION, 353..358 > note, His6 - REGION, 348..352 > note, GGGGS-linker Residues: EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60 LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GNTHGMPCMF PFQYNHQWHH ECTREGREDD 180 LLWCATTSRY ERDEKWGFCP DPTSAEVGCD TIWEKDLNSH ICYQFNLLSS LSWSEAHSSC 240 QMQGGTLLSI TDETEENFIR EHMSSKTVEV WMGLNQLDEH AGWQWSDGTP LNYLNWSPEV 300 NFEPFVEDHC GTFSSFMPSA WRSRDCESTL PYICKKYLNH IDHEIVEGGG GSHHHHHHGG 360 GECS 364 Sequence Number (ID): 149 Length: 1408 Molecule Type: AA Features Location/Qualifiers: - source, 1..1408 > mol_type, protein > organism, synthetic construct - REGION, 1398..1408

266 30124-WO-PCT > note, His10 - REGION, 1383..1397 > note, Avi tag GLNDIFEAQKIEWHE - REGION, 1377..1382 > note, GGSGGS linker - REGION, 1..141 > note, CysR - REGION, 153..201 > note, FnII region Residues: EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60 LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GNTHGMPCMF PFQYNHQWHH ECTREGREDD 180 LLWCATTSRY ERDEKWGFCP DPTSAEVGCD TIWEKDLNSH ICYQFNLLSS LSWSEAHSSC 240 QMQGGTLLSI TDETEENFIR EHMSSKTVEV WMGLNQLDEH AGWQWSDGTP LNYLNWSPEV 300 NFEPFVEDHC GTFSSFMPSA WRSRDCESTL PYICKKYLNH IDHEIVEKDA WKYYATHCEP 360 GWNPYNRNCY KLQKEEKTWH EALRSCQADN SALIDITSLA EVEFLVTLLG DENASETWIG 420 LSSNKIPVSF EWSNDSSVIF TNWHTLEPHI FPNRSQLCVS AEQSEGHWKV KNCEERLFYI 480 CKKAGHVLSD AESGCQEGWE RHGGFCYKID TVLRSFDQAS SGYYCPPALV TITNRFEQAF 540 ITSLISSVVK MKDSYFWIAL QDQNDTGEYT WKPVGQKPEP VQYTHWNTHQ PRYSGGCVAM 600 RGRHPLGRWE VKHCRHFKAM SLCKQPVENQ EKAEYEERWP FHPCYLDWES EPGLASCFKV 660 FHSEKVLMKR TWREAEAFCE EFGAHLASFA HIEEENFVNE LLHSKFNWTE ERQFWIGFNK 720 RNPLNAGSWE WSDRTPVVSS FLDNTYFGED ARNCAVYKAN KTLLPLHCGS KREWICKIPR 780 DVKPKIPFWY QYDVPWLFYQ DAEYLFHTFA SEWLNFEFVC SWLHSDLLTI HSAHEQEFIH 840 SKIKALSKYG ASWWIGLQEE RANDEFRWRD GTPVIYQNWD TGRERTVNNQ SQRCGFISSI 900 TGLWGSEECS VSMPSICKRK KVWLIEKKKD TPKQHGTCPK GWLYFNYKCL LLNIPKDPSS 960 WKNWTHAQHF CAEEGGTLVA IESEVEQAFI TMNLFGQTTS VWIGLQNDDY ETWLNGKPVV 1020 YSNWSPFDII NIPSHNTTEV QKHIPLCALL SSNPNFHFTG KWYFEDCGKE GYGFVCEKMQ 1080 DTSGHGVNTS DMYPMPNTLE YGNRTYKIIN ANMTWYAAIK TCLMHKAQLV SITDQYHQSF 1140 LTVVLNRLGY AHWIGLFTTD NGLNFDWSDG TKSSFTFWKD EESSLLGDCV FADSNGRWHS 1200 TACESFLQGA ICHVPPETRQ SEHPELCSET SIPWIKFKSN CYSFSTVLDS MSFEAAHEFC 1260 KKEGSNLLTI KDEAENAFLL EELFAFGSSV QMVWLNAQFD GNNETIKWFD GTPTDQSNWG 1320 IRKPDTDYFK PHHCVALRIP EGLWQLSPCQ EKKGFICKME ADIHTAEALP EKGPSHSGGS 1380 GGSGLNDIFE AQKIEWHEHH HHHHHHHH 1408 Sequence Number (ID): 150 Length: 1408 Molecule Type: AA

267 30124-WO-PCT Features Location/Qualifiers: - source, 1..1408 > mol_type, protein > organism, synthetic construct - REGION, 1398..1408 > note, His10 - REGION, 1383..1397 > note, Avi tag GLNDIFEAQKIEWHE - REGION, 1377..1382 > note, GGSGGS linker - REGION, 1..140 > note, Full length ectodomain - REGION, 141..146 > note, Thrombin cleavage site engineered to cleave off Cys R domain (thrombin sequence replacing Y161-L166) Residues: EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60 LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE LVPRGSHTIK GNTHGMPCMF PFQYNHQWHH ECTREGREDD 180 LLWCATTSRY ERDEKWGFCP DPTSAEVGCD TIWEKDLNSH ICYQFNLLSS LSWSEAHSSC 240 QMQGGTLLSI TDETEENFIR EHMSSKTVEV WMGLNQLDEH AGWQWSDGTP LNYLNWSPEV 300 NFEPFVEDHC GTFSSFMPSA WRSRDCESTL PYICKKYLNH IDHEIVEKDA WKYYATHCEP 360 GWNPYNRNCY KLQKEEKTWH EALRSCQADN SALIDITSLA EVEFLVTLLG DENASETWIG 420 LSSNKIPVSF EWSNDSSVIF TNWHTLEPHI FPNRSQLCVS AEQSEGHWKV KNCEERLFYI 480 CKKAGHVLSD AESGCQEGWE RHGGFCYKID TVLRSFDQAS SGYYCPPALV TITNRFEQAF 540 ITSLISSVVK MKDSYFWIAL QDQNDTGEYT WKPVGQKPEP VQYTHWNTHQ PRYSGGCVAM 600 RGRHPLGRWE VKHCRHFKAM SLCKQPVENQ EKAEYEERWP FHPCYLDWES EPGLASCFKV 660 FHSEKVLMKR TWREAEAFCE EFGAHLASFA HIEEENFVNE LLHSKFNWTE ERQFWIGFNK 720 RNPLNAGSWE WSDRTPVVSS FLDNTYFGED ARNCAVYKAN KTLLPLHCGS KREWICKIPR 780 DVKPKIPFWY QYDVPWLFYQ DAEYLFHTFA SEWLNFEFVC SWLHSDLLTI HSAHEQEFIH 840 SKIKALSKYG ASWWIGLQEE RANDEFRWRD GTPVIYQNWD TGRERTVNNQ SQRCGFISSI 900 TGLWGSEECS VSMPSICKRK KVWLIEKKKD TPKQHGTCPK GWLYFNYKCL LLNIPKDPSS 960 WKNWTHAQHF CAEEGGTLVA IESEVEQAFI TMNLFGQTTS VWIGLQNDDY ETWLNGKPVV 1020 YSNWSPFDII NIPSHNTTEV QKHIPLCALL SSNPNFHFTG KWYFEDCGKE GYGFVCEKMQ 1080 DTSGHGVNTS DMYPMPNTLE YGNRTYKIIN ANMTWYAAIK TCLMHKAQLV SITDQYHQSF 1140 LTVVLNRLGY AHWIGLFTTD NGLNFDWSDG TKSSFTFWKD EESSLLGDCV FADSNGRWHS 1200 TACESFLQGA ICHVPPETRQ SEHPELCSET SIPWIKFKSN CYSFSTVLDS MSFEAAHEFC 1260 KKEGSNLLTI KDEAENAFLL EELFAFGSSV QMVWLNAQFD GNNETIKWFD GTPTDQSNWG 1320

268 30124-WO-PCT IRKPDTDYFK PHHCVALRIP EGLWQLSPCQ EKKGFICKME ADIHTAEALP EKGPSHSGGS 1380 GGSGLNDIFE AQKIEWHEHH HHHHHHHH 1408 Sequence Number (ID): 151 Length: 1408 Molecule Type: AA Features Location/Qualifiers: - source, 1..1408 > mol_type, protein > organism, synthetic construct Residues: EGVAAALTPE RLLEWQDKGI FVIQSESLKK CIQAGKSVLT LENCKQANKH MLWKWVSNHG 60 LFNIGGSGCL GLNFSAPEQP LSLYECDSTL VSLRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GNTHGMPCMF PFLVPRGSHH ECTREGREDD 180 LLWCATTSRY ERDEKWGFCP DPTSAEVGCD TIWEKDLNSH ICYQFNLLSS LSWSEAHSSC 240 QMQGGTLLSI TDETEENFIR EHMSSKTVEV WMGLNQLDEH AGWQWSDGTP LNYLNWSPEV 300 NFEPFVEDHC GTFSSFMPSA WRSRDCESTL PYICKKYLNH IDHEIVEKDA WKYYATHCEP 360 GWNPYNRNCY KLQKEEKTWH EALRSCQADN SALIDITSLA EVEFLVTLLG DENASETWIG 420 LSSNKIPVSF EWSNDSSVIF TNWHTLEPHI FPNRSQLCVS AEQSEGHWKV KNCEERLFYI 480 CKKAGHVLSD AESGCQEGWE RHGGFCYKID TVLRSFDQAS SGYYCPPALV TITNRFEQAF 540 ITSLISSVVK MKDSYFWIAL QDQNDTGEYT WKPVGQKPEP VQYTHWNTHQ PRYSGGCVAM 600 RGRHPLGRWE VKHCRHFKAM SLCKQPVENQ EKAEYEERWP FHPCYLDWES EPGLASCFKV 660 FHSEKVLMKR TWREAEAFCE EFGAHLASFA HIEEENFVNE LLHSKFNWTE ERQFWIGFNK 720 RNPLNAGSWE WSDRTPVVSS FLDNTYFGED ARNCAVYKAN KTLLPLHCGS KREWICKIPR 780 DVKPKIPFWY QYDVPWLFYQ DAEYLFHTFA SEWLNFEFVC SWLHSDLLTI HSAHEQEFIH 840 SKIKALSKYG ASWWIGLQEE RANDEFRWRD GTPVIYQNWD TGRERTVNNQ SQRCGFISSI 900 TGLWGSEECS VSMPSICKRK KVWLIEKKKD TPKQHGTCPK GWLYFNYKCL LLNIPKDPSS 960 WKNWTHAQHF CAEEGGTLVA IESEVEQAFI TMNLFGQTTS VWIGLQNDDY ETWLNGKPVV 1020 YSNWSPFDII NIPSHNTTEV QKHIPLCALL SSNPNFHFTG KWYFEDCGKE GYGFVCEKMQ 1080 DTSGHGVNTS DMYPMPNTLE YGNRTYKIIN ANMTWYAAIK TCLMHKAQLV SITDQYHQSF 1140 LTVVLNRLGY AHWIGLFTTD NGLNFDWSDG TKSSFTFWKD EESSLLGDCV FADSNGRWHS 1200 TACESFLQGA ICHVPPETRQ SEHPELCSET SIPWIKFKSN CYSFSTVLDS MSFEAAHEFC 1260 KKEGSNLLTI KDEAENAFLL EELFAFGSSV QMVWLNAQFD GNNETIKWFD GTPTDQSNWG 1320 IRKPDTDYFK PHHCVALRIP EGLWQLSPCQ EKKGFICKME ADIHTAEALP EKGPSHSGGS 1380 GGSGLNDIFE AQKIEWHEHH HHHHHHHH 1408 Sequence Number (ID): 152 Length: 362

269 30124-WO-PCT Molecule Type: AA Features Location/Qualifiers: - source, 1..362 > mol_type, protein > organism, synthetic construct - MOD_RES, 102..123 > note, ITGPLQYSVQVAHDNTVVASRK (S10+GalNae)(T18+GalNAc.6GGn.3G)(S22+GalNAc- 6GGn-3G)(5+) - MOD_RES, 339..362 > note, NHIDHEIVEGGGGSLPETGGGGG (C26-sortase_2GnlNnc)(4+) - MOD_RES, 196..205 > note, WGFCPDPTSAEVGCDTIWEK (T8+GalNAc-6S-3SG)(3+) Residues: EGVAAALTPE RLLEWQDKGI FVIQSESIKK CIQAGKSVLT LENCKQANKH MIWKWVSNHG 60 LENIGGSGCL GLNFSAPEQP LSLYECDSTL VSIRWRCNRK MITGPLQYSV QVAHDNTVVA 120 SRKYIHKWIS YGSGGGDICE YLHKDLHTIK GNTHGMPCMF PFQYNHOWHH ECTREGREDD 180 LLWCATTSRY ERDEKWGFCP DPTSAEVGCD TIWEKDINSH ICYQFNLLSS LSWSEAHSSC 240 QMQGGTLLSI TDETEENFIR EHMSSKTVEV WMGLNOLDEH AGWOWSDGIP LNYLNWSPEV 300 NFEPFVEDHC GIFSSEMPSA WRSRDCESTL PYICKKYLNH IDHETIVEGG GGSLPETGGG 360 GG 362

270 30124-WO-PCT

Claims

CLAIMS 1. A composition of matter comprising: an anti-PLA2R antibody-binding moiety, and a cellular receptor-binding moiety capable of binding to hepatocytes or other degrading cells through asialoglycoprotein receptors (ASGPR) of hepatocytes or other cell receptors on surface degrading cells, wherein the anti-PLA2R antibody-binding moiety and the cellular receptor-binding moiety are covalently connected, optionally through a linker moiety connecting the anti-PLA2R antibody-binding moiety and the cellular receptor-binding moiety.

2. The composition of matter of Claim 1, having a structure of: R^CN−(Xaa)y−R^CC, or a salt thereof.

271 30124-WO-PCT

3. The composition of matter of claim 1, wherein the composition of matter is selected from the group consisting of AGN302, AGN303, AGN304, AGN306, AGN307, AGN308, AGN309, AGN310, AGN362, AGN363, AGN364, AGN365, AGN579, AGN580, and AGN167.

4. The composition of matter of claim 1, wherein the anti-PLA2R antibody-binding moiety is selected from the group of compounds listed in TABLE 72.

5 The composition of matter of claim 1, wherein the anti-PLA2R antibody-binding moiety is a peptide selected from the groups of secretory phospholipase A2 receptor peptides in SEQ ID NO: 60- 145.

6 The composition of matter of claim 1, wherein the anti-PLA2R-autoantibody-binding moiety is selected from the group consisting of ABT301, ABT305, ABT309, ABT310, ABT311, ABT312, ABT407, ABT408, ABT409, ABT427, ABT530, ABT603, ABT606, ABT816, ABT817, ABT818, ABT819, ABT976, ABT983, and ABT985.

7. The composition of matter of claim 1, wherein the cellular receptor-binding moiety has the structure: ; groups, preferably R^A is a methyl or ethyl group optionally substituted with from 1-3 fluoro groups; Z_A is -(CH₂)_IM, -O-(CH₂)_IM, S-(CH₂)_IM, NR_M-(CH₂)_IM, C(O)-(CH₂)_IM-, a PEG group containing from 1 to 8 preferably 1-4 ethylene glycol residues or a -C(O)(CH₂)_IMNR_M group (preferably a PEG containing group comprising from 1 to 8 ethylene glycol, preferably 2-4 ethylene glycol residues); and Z_B is absent, (CH₂)_IM, C(O)-(CH₂)_IM- or C(O)-(CH₂)_IM-NR_M.

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8. The composition of matter of claim 1, wherein the cellular receptor-binding moiety is selected from the group consisting of TBT103, TBT104, TBT105, TBT307, TBT506, and TBT544.

9. The composition of matter of claim 1, for use as a medicament.

10. The composition of matter of claim 1, for use in removing anti-PLA2R-autoantibody from a subject.

11. The composition of matter of claim 1, for use in treating a disease state or condition associated with the upregulation of anti-PLA2R-autoantibody in a subject or patient.

12. The composition of matter of claim 1, for use in treating membranous nephropathy.

13. A method of making the composition of matter of claims 1-8, wherein the method comprises a conjugation step to link an anti-PLA2R-autoantibody-binding moiety to a cellular receptor-binding moiety through a linker moiety, wherein the conjugation step is selected from the group consisting of a MATE conjugation step, a maleimide conjugation step, and a sortase conjugation step.

14. A pharmaceutical composition comprising the composition of matter of claims 1-8 and a pharmaceutically acceptable excipient.

15. A method of removing anti-PLA2R-autoantibody from a subject or patient comprising administering to the subject or patient the composition of matter of any of claims 1-8.

16. A method of treating a disease state or condition associated with the upregulation of anti- PLA2R-autoantibody in a subject or patient comprising administering to the subject or patient an effective amount of the composition of matter of any of claims 1-8.

17. A method of treating membranous nephropathy in a subject or patient comprising administering to the subject or patient an effective amount of the composition of matter of any of claims 1-8.

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18. A composition comprising: a first composition of matter comprising: an anti-PLA2R-autoantibody-binding moiety, a cellular receptor-binding moiety capable of binding to hepatocytes or other degrading cells through asialoglycoprotein receptors (ASGPR) of hepatocytes or other cell receptors which are on surface degrading cells, and a linker moiety connecting the anti-PLA2R-autoantibody-binding moiety and the cellular receptor-binding moiety, and at least one additional composition of matter comprising a moiety comprising: a cellular receptor-binding moiety capable of binding to hepatocytes or other degrading cells through asialoglycoprotein receptors (ASGPR) of hepatocytes or other cell receptors which are on surface degrading cells, and a linker moiety connecting the anti-PLA2R-autoantibody-binding moiety and the cellular receptor-binding moiety.

19. The composition of claim 18, wherein the additional agent has a structure selected from the ^{group consisting of formula LG−RG−LRM} _{(−TBT)b,, LG−RG−H, and a combination thereof.}

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