WO1990014358A1

WO1990014358A1 - T-lymphotropic retrovirus monoclonal antibodies

Info

Publication number: WO1990014358A1
Application number: PCT/US1990/002874
Authority: WO
Inventors: Bryan T. Butman; Thomas M. Venetta
Original assignee: Akzo N.V.
Priority date: 1989-05-15
Filing date: 1990-05-14
Publication date: 1990-11-29
Also published as: KR0168447B1; ZA903492B; FI915333A7; EP0472659A1; AU642886B2; CA2032509A1; EP0472659A4; JPH04505621A; FI915333A0; KR920701243A; AU5835590A

Abstract

The instant invention relates to monoclonal antibodies, the cell lines producing those antibodies, the peptides that comprise the epitopes of those antibodies and assays using those antibodies and peptides for the detection of HIV-1 and HIV-2 gene products. In particular, the antibodies react with the p24/p26 capsid protein, the nonapeptide that comprises an HIV-1/HIV-2 conserved epitope is disclosed and a capture ELISA using a combination of three monoclonal antibodies that can detect simultaneously HIV-1 and HIV-2 is disclosed.

Description

-I

TITLE OF THE INVENTION

T-LYMPHOTROPIC RETROVIRUS MONOCLONAL ANTIBODIES

FIELD OF THE INVENTION

The invention relates to monoclonal antibodies, peptides that comprise the epitopes of said monoclonal antibodies and assays utilizing said monoclonal antibodies and said peptides for the detection of T- lymphotropic retroviruses, particularly HIV-1, HIV-2 and SIV.

BACKGROUND OF THE INVENTION

The T-lymphotropic retrovirus family includes among other lentiviruses the simian retrovirus SIV and the human retroviruses HIV-1 (the likely etiologic agent of AIDS) and HIV-2. Although HIV-1 and HIV-2 are related evolutionally, nucleic acid sequence analysis reveals that HIV-2 is more closely related to SIV than it is to HIV-1. Guyader et al. (1987) noted only 42% overall genomiσ sequence identity between the HIV-1 and HIV-2 isolates they compared. Patients infected with HIV-2 can manifest disorders that typify AIDS, purely neurologic disease or asymptomatic infections (Kuhnel et al., 1988) despite HIV-1-related ultrastructural and biological properties such as in vitro cytopathogenicity and CD4 tropism (Clavel et al., 1986). The HIV-1 and HIV-2 genomes have a typical retroviral configuration comprising LTR's, αaα and env regions that encode viral structural proteins, sequences encoding one or more enzyme, including a reverse transcriptase and other ORF's and regulatory elements. The aσ region of HIV-1 encodes a precursor peptide known as p55. p55 is processed to produce among other proteins the major core or capsid protein known as p24. In HIV-2, the analogous crag precursor is larger, known as p57, and the major core protein is known as p26. Although a high degree of conservation of the σaσ proteins of HIV-1 and HIV-2 was expected, Guyader et al. (1987) found only 58% identity of amino acids between HIV-1 and HIV-2 crag proteins. -_ Even among distant isolates of HIV-1 there is a greater than 90% identity of gag proteins. That and other data support the hypothesis that although HIV-1 and HIV-2 are somewhat related, they are nevertheless distinct retroviral species.

Because HIV-1 and possibly HIV-2 have such an impact on the human immune system, it is desirable, in fact imperative that sensitive, rapid diagnostic assays for detecting presence of HIV be available for population screening, quality control in blood banks, diagnosis, furtherance of our understanding of those viruses to assure the goal of obtaining a vaccine and cure, and the like. Because of ease and convenience, it is preferable that the assays be immunology-based, such as ELISA's, and for reproducibility, specificity and consistency that the reagents be monoclonal antibodies and defined antigenic peptides. Because p24 antigenemia has been shown to be an early sign of HIV infection (Kessler et al., 1987; Wall et al., 1987) and the observation that clinical progression of AIDS sequelae is associated with reduction in anti-p24 while patients with AIDS can die with high levels of anti-env titers (Coates et al., 1987), it would be advantageous for the assay to be directed to detecting gag products such as p24/p26.

Weiss et al. (1988) identified human serum samples that contained antibodies specific to HIV-2 gpl30 in radioimmunoprecipitation assays and in ELISA*s. Those antibodies showed low level HIV-1 crossreactivity in a VSV pseudotype neutralization assay and in a neutralization of C8166 syncytia formation assay.

Minassian et al. described a monoclonal antibody identified as R1C7 that was raised against HIV-2. R1C7, an anti-capsid antibody (p26) , reacted not only with the three HIV-2 isolates tested, but with the five HIV-l^' isolates and seven SIV isolates that were tested. In immunoblots, R1C7 bound to 55KD and 26KD HIV-2 proteins, to 24KD and 55KD HIV-l proteins and to a 28KD SIV protein.

Niedrig et al. developed a panel of 29 monoclonal antibodies to HIV-l. One antibody was directed to pl7 and its precursor p32 whereas the remainder reacted with p24 and some of those also reacted with p55. The pl7 antibody was found to be HIV-l specific. Of the 28 anti-p24 antibodies, 20 reacted in immunoblots with the corresponding capsid protein (p 6) of HIV-2 and five of those also recognized the corresponding SIV protein, p28. Niedrig et al. make no mention of antibody titer, the efficacy of the antibodies in a antigen capture assay or which of the antibodies bind to p26, p55 or both. Furthermore, several of antibodies reacted with a 22KD protein of unknown function in HIV-2 preparations.

Many diagnostic kits and assays have been developed for the detection of HIV-l in samples of sera, blood, blood products or other body tissues. The assays use a variety of techniques such as Western blot, enzyme- linked immunosorbent assay (ELISA) or indirect immuno- fluorescent assay and employ either antibodies to whole virus or purified viral antigens, see for example, Gallo et al., U.S. Patent No. 4,520,113; Sarngadharan, et al., (1984); and Robert-Guroff et al. (1982). SUMMARY OF THE INVENTION

The instant invention relates to monoclonal antibodies, the cell lines producing those antibodies, the peptides that comprise the epitopes of those antibodies and assays using those antibodies and peptides for the detection of HIV-l and HIV-2 gene products as well as SIV gene products. In particular, the antibodies react with the p24/p26 capsid protein. The nonapeptide that comprises an HIV-l/HIV-2 conserved epitope is disclosed and a capture ELISA using a combination of three monoclonal antibodies that can detect simultaneously HIV-l and HIV-2 is disclosed.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1. Graph depicting reactivity of culture supernatants in capture ELISA. A detailed legend appears in Table 1. Figure 2. Photograph of immunoblot nitrocellulose strips determining the specificity of anti-HIV antibodies.

Figure 3. Protein A-purified antibodies were used as probe to separated HIV-2 proteins in immunoblots. Lanes 1 and 2 are positive controls and Lane 3 is a negative control.

Figure 4. Diagram of some of the recombinant p24 peptides used to map epitopes.

Figure 5. Diagram of four regions of p24 to which various monoclonal antibodies bind.

Figure 6. Photographs of Westerns reacting various monoclonals with blotted gag and gag fragments. Lane 1 in each photo contains whole virus lysate. Lane 5 in each photo is a negative control p24^" plasmid and Lane 6 in each photo is another negative control containing non-HIV-infected MOLT lysate. Figure 7. Graph representing results of ELISA's using sequential overlapping nonapeptides as antigen to determine epitope of 7-D4.

Figure 8. Diagram depicting epitope mapping using sequential overlapping nonapeptides as antigen in ELISA.

Figure 9. Composition of the regions that comprise the 7-D4 epitope.

Figure 10. Graph of sensitivity of a capture ELISA using two anti-p24 antibodies, 6-C10 and 5-B4, on the solid phase and HIV-l infected MOLT 3 lysate as the antigen. An HRP conjugated human anti-HIV was the reporter.

Figure 11. Graph of sensitivity of a capture ELISA using 6-C10 and 5-B4 with and without 7-D4 on the solid phase to detect p26 of HIV-2.

Figure 12. Dose response curve for HIV-l and HIV- 2 in a capture ELISA using 6-C10, 5-B4 and 7-D4.

Figure 13. Comparison of HIV-l dose response curves between the three antibody capture ELISA and a reverse transcriptase assay.

DETAILED DESCRIPTION OF THE INVENTION

The instant invention relates to monoclonal antibodies and their production, im unoassays and oligopeptides. The methods that were used are known in the art and are discussed only briefly throughout the specification. Suitable methods to practice the invention may be found in Meth Enzymology 121_r (1986) and other available reference materials.

Preparation of Monoclonal Antibodies

Monoclonal antibodies were produced according to established procedures (Kohler & Milstein, 1975) .

Briefly, female BALB/c mice were immunized intraperitoneally repeatedly with lysates of HIV-l infected MOLT 3 cells emulsified in complete Freund's adjuvant (50%) . Sensitized spleen cells were fused with P3X63-Ag8.653 myeloma cells using PEG 1500. Heterokaryons were selected in HAT medium, cloned and screened for reactivity to HIV antigens in a capture ELISA. The IgG fraction of polyclonal human anti-HIV was coated onto wells of icrotiter dishes. HIV-l (produced in MOLT 3 cells) and culture supernatants were added simultaneously to the wells. Bound murine antibodies were detected with an enzyme-labelled anti- mouse Ig antibody. Data representative of the screening is depicted in Figure 1. Designation of the sample numbers is set forth in Table 1.

Table 1

ELISA Screening of Fusion F86

Sample No. Designation

1 5-B4

2 5-D9

3 5-E2

4 5-F12 5 6-B9

6 4-E6

7 6-C10

8 6-E11

9 6-F6 10 10-B2

11 10-C12

12 10-D1

13 2-C8

14 7-D4 15 7-E1

16 7-E10 Table 1

ELISA Screening of Fusion 786 - (cont'd)

Sample No. Designation

17 7-F3 18 8-E7 19 9-B7 20 9-D5 21 F86 Bleedout* 22 NMS** 23 Negative Control

* Serum obtained at sacrifice ** Normal Mouse Serum

Western Blots

Candidate anti-HIV clones were tested further in Western blots (Towbin et al., 1979). Lysates of HIV- infected MOLT 3 cells were separated through a 12% acrylamide gel under denaturing conditions. The proteins were transferred to nitrocellulose and individual strips were blocked and reacted with the culture supernatants. Bound antibody was detected using an enzyme-labelled goat anti-mouse Ig antibody. Antibodies reacting specifically with p24 were selected (Figure 2) . Designation of the strips is set forth in Table 2. Table 2

Western Blot Analysis of Anti-p2 aAbs

Str p #

Designation

1

Positive Control

2 5-B4

3 5-D9

4 5-E2

5 5-F12

6 Positive Control

7 6-B9

8 6-C9

9 6-C10

10 6-E11

11 Positive Control

12 6-F6

13 10-B2

14 10-C12

15 Positive Control

16 10-D1

17 10-H1

18 7-D4

19 Positive Control

20 7-E1

21 7-E10

22 7-F3

23 8-E7

24 Positive Control

25 9-B7

26 9-D5 The anti-p24 antibodies were then tested for cross- reactivity to p26 of HIV-2 in immunoblots. HIV-2 lysates were separated, blotted and reacted with the anti-p24 antibodies. Two antibodies, 7-D4 and 5-D9 reacted strongly with p26 (Figure 3). Designation of the strips is set forth in Table 3.

Table 3

Cross-Reactivity of An i-p24 mAbs with p26 of HIV-2

Strip mAb

I Hu-anti-HIV-1 IgG 2 OSS 39-B-3

3 MOPC 21 (IgGl)

4 F86/ 5-B4

5 5-D9

6 6-C10 7 7-E10

8 5-E2

9 9-B7

10 7-F3

II 6-F6 12 9-D5

13 7-D4

14 6-E11

15 7-E1

In a related experiment, 7-D4 recognized a protein of approximately 27,000 molecular weight in lysates of SIV^c, Epitooe Mapping

The amino acids that comprise the p24 epitope of 7- D4 were mapped in the following manner. The gag region and portions of gag were subcloned in an expression vector. Briefly, viral DNA of a

bacteriophage (cDNA library HIV-l^., clone HAT 3 (Starcich et al., (1986)) was digested with EcoRI and by ligation into the pBR322- derived plasmid pMLB1113 to produce a plasmid identified as clone 29 which contained the EcoRI/SstI gag/pol ORF. Clone 29 was digested with SstI to remove extraneous vector sequences and religated to produce plasmid gag/pol 1.2. This latter plasmid was sonicated, blunt- ended and ligated with EcoRI linkers. The mixture was then digested with EcoRI. ligated into AORF8 (Meissner et al. 1987) and packaged. A AORF8 expression library was generated in E. coli and screened with a human anti- HIV polyclonal antibody and a mouse anti-p24 (HIV-l) monoclonal antibody. The positives were selected, expanded and the expressed peptides were characterized by Western blotting, immunoassay and nucleotide sequencing. The recombinant p24 peptides gag 8, gag 126, gag 107 and gag 141 were expressed in E. coli. Separately, clone 29 was used as a template and oligonucleotides corresponding to the 5" and 3' ends of the published sequence were used in a polymerase chain reaction to generate a complete sequence of the gag protein p24. The 5' end contained an EcoRI site and the 3• end contained a IJamHI site. The reaction product was digested with EcoRI and B_amHI and then ligated into PMLB1113. A recombinant p24 protein, gag 24.5, was expressed in IL. coli. The characterization of the recombinant p24 peptides is presented in Figure 4.

The various recombinant p24 peptides were used as antigen in ELISA's and in Western blots to determine whether or not a given monoclonal antibody bound a given peptide. The reactivity pattern of any one monoclonal antibody with the panel of p24 peptides allowed a localization of the recognized epitope to one of four regions as shown in Table 4 and Figures 5 and 6.

Table 4

Immunochemical Analysis of Anti-24 nAbs using Recombinant Peptides

gag gag gag gag gag mAb mAb 24.5 8 126 107 l≤JL ppup

5-B4 + - + - - B

5-D9 + + + - - C

5-E2 + + - - - D

5-F12 + - + - - B

6-C10 + + + - - C

6-E11 + - - - - A

6-F6 + - - - - A

7-D4 + - + - - B

7-E1 + - + - - B

7-E10 + + - - - D

7-F3 + - + - - B

8-E7 + - - - - A

9-B7 + + - - - D

9-D5 + - - - - A

10-B2 + - + - - B

10-C12 + A

Because 7-D4 bound only to gag 24.5 and gag 126, it was possible to deduce that the 7-D4 epitope mapped to region B delimited by amino acid residues 142-209. To further localize the epitope of 7-D4, synthetic sequential overlapping nonapeptides were made for the B region of p24. Each nonapeptide served as the solid phase antigen in a series of ELISA's to determine maximal binding affinity of the monoclonal. A single peak of reactivity was found (Figure 7) for a linear domain comprising the region containing amino acids 142- 158 (Figure 8) .

A comparison of the amino acid sequences of p24 of an HIV-l isolate, p26 of an HIV-2 isolate and p27 of SIV_KAC revealed conservation of a decapeptide (Figure 9) within the epitope of p24 consisting of Ser-Pro-Arg-Thr- Leu-Asn-Ala-Trp-Val-Lys. It can be inferred that the region encompassing the decapeptide is the 7-D4 epitope of p26 in HIV-2 and p27 in SIV^.

The values of a defined epitope are known to those skilled in the art. One of the benefits is the ability of generating new antibodies capable of reacting with said epitope and similar epitopes. Synthetic peptides are configured after the epitope sequence and either unmodified or conjugated to carriers are used as antigen. For example, peptides can be conjugated to PPD, tetanus toxoid, KLH or BSA using glutaraldehyde, carbodiimide or N-maleimidobenzoyl hydroxuccinimide ester. For a review of using synthetic peptides as antigen, see Ciba Foundation Symposium 119 (1986) John Wiley and Sons, NY. Antibodies may be raised n vivo as in mice, goats or other lab animals or in vitro using a system of materials and methods similar to the IVIS of Hana Biologies (Alameda, CA) . Another benefit is that large quantities of the epitope sequence can be produced synthetically or using standard recombinant DNA techniques as described above and the peptides can serve as antigen in immunology-based assays and kits for the detection of circulating antibody or for the detection of circulating antigen in an inhibition type assay. Another benefit relates to improving the assays disclosed herein. Without extending the survey, it is unclear whether the epitope identified in the HIV-l isolate described herein is specific to that isolate and furthermore to the HIV-2 and SIV isolates described herein. Using that sequence as a reference point, the epitope can be engineered, that is substituting one or more amino acids or alternatively derivitizing the epitope, etc., with a view to identifying a related sequence with a greater degree of conservation among a larger variety of HIV isolates or to obtaining a related sequence with a greater degree of reactivity in assays. Although the nonapeptide analysis apparently identified a discrete linear epitope comprised of amino acids 142- 158 of the HIV-l gag that is conserved in HIV-2 and SIV, it is to be understood that the instant invention relates to monoclonal antibodies, epitopes of said monoclonal antibodies and assays using said antibodies and said peptides that are capable of detecting gag encoded proteins of HIV-l, HIV-2 and SIV.

Capture ELISA Assay

To determine which of the monoclonals would find utility in an ELISA, each was used as a capture or HRP- conjugate antibody in a sandwich assay. Briefly, the monoclonal antibody was coated on wells and 10 μl of disruption buffer added. The antigen samples suspended in detergent buffer or controls in a volume of 100 μl were added next and incubated at 37^βC for 90 minutes.

After washing, bound antigen was detected by adding to the wells an enzyme conjugated anti-HIV reagent

(horseradish peroxidase-conjugated human anti-HIV IgG, affinity purified, 100 μl) and incubated at 37^βC for 30 minutes. After washing several times, 100 μl of substrate solution were added to the wells and incubated at room temperature for 30 minutes. 100 μl of stop reagent were added and absorbance read at 450 nm using an air blank. Representative data are presented in Table 5.

Table 5

Checkerboard Analysis of mλbs

Capture Antibody 5B4 5D9 5E2 §£10. 6£U 7B10 9B7 HαHIV

5B4 0.12 0.26 0.29 0.82 0.13 1.03 0.17 2.67

5D9 0.73 0.13 0.43 0.62 0.37 0.38 0.12 >3.0

5E2 0.58 0.47 0.14 0.61 0.23 0.80 0.11 2.51

6C10 0.81 0.38 0.44 0.20 0.17 0.70 0.13 >3.0

6E11 0.09 0.21 0.21 0.14 0.16 0.27 0.09 0.41

7E10 0.84 0.43 0.49 0.84 0.18 0.18 0.13 >3.0

9B7 0.14 0.11 0.10 0.17 0.13 0.17 0.13 0.28

34A 0.49 0.12 0.08 0.96 0.28 1.81 0.22 >3.0

Purified mAb were coated overnight at 10 μg/ml. HRP-mAb used at 10 μg/ml added at beginning of incubation (90' at 37°C) .

HRP-human-anti-HIV was added after 60 min.

Absorbances given for 10.0 ng/ml HIV-l MOLT 3 in NHS.

Absorbance for NHS was 0.12 ± 0.03

Antibodies 5-B4, 6-C10 and 7-E10 worked best as both capture and conjugated antibodies. Maximal signals were obtained with the HRP-human anti-HIV as the conjugate.

Various combinations of the monoclonals were used as capture antibodies in ELISA's. The combination of 5- -15-

B4 and 6-C10 showed the greatest sensitivity in detecting p24 (Figure 10). To detect p26 of HIV-2, 7- D4 was used as a capture antibody (Figure 11) . It was found that maximal sensitivity and robustness occurred 5 when the three antibodies, 5-B4, 6-C10 and 7-D4 were combined as capture antibodies. Under those conditions, p26 was detectable as well as p24 from certain borderline clinical samples that were difficult to interpret when only 5-B4 and 6-C10 were used as capture

10 antibodies. The sensitivity of the capture ELISA using these three antibodies is less than 10 pg/ml (less than 1 pg/well) of HIV-l p24 antigen and less than 0.5 ng/ml of HIV-2 p26 antigen (Figure 12) . The sensitivity is found despite the presence of HIV antibodies in the

15 clinical samples. A capture ELISA using the three antibodies 5-B4, 6-C10 and 7-D4 was also compared to a reverse transcriptase assay for the detection of whole virus. The ELISA was 25,000 times more sensitive than the reverse transcriptase assay (Figure 13) .

20

While the invention has been disclosed in this patent application by reference to the details of preferred embodiments of the invention, it is to be understood that this disclosure is intended in an

25 illustrative rather than in a limiting sense, as it is contemplated that modifications will readily occur to those skilled in the art, within the spirit of the invention and the scope of the appended claims. References

1. Clavel, F., et al., Science 233. 343 (1986)

2. Coates, A., et al., Nature 326. 549 (1987)

3. Guyader, M., et al.. Nature 326. 662 (1987)

4. Kessler, H. , et al., J Am Med Assoc 258. 1196 (1987)

5. Kohler, G, & Milstein, C., Nature 2≤£, 495 (1975)

6. Kuhnel, H. , et al., Proc Natl-Acad Sci USA 86. 2383 (1989)

7. Marlink, R. , et al., AIDS Res Hum Retroviruses 4., 137 (1988)

8. Minassian, A., et al., Proc Natl Acad Sci USA 85. 6939 (1988)

9. Meissner, P.S. et al., Proc Natl Acad Sci USA 84. 4171 (1987)

10. Niedrig, M. , et al., J Gen Virol 69, 2109 (1988)

11. Robert-Guroff, R.C. et al., Science 215. 975 (1982)

12. Sarngadharan, M.G., et al., Science 224. 506 (1984)

13. Starcich, B.R., et al.. Cell 45. 637 (1986)

14. Towbin, H. et al., Proc Natl Acad Sci USA TjS, 4350 (1979)

15. Wall, R., et al.. Lancet i. 566 (1987)

16. Weiss, R., et al., AIDS 2. 95 (1988)

Claims

WHAT IS CLAIMED IS:

1. A monoclonal antibody which reacts with an epitope of p24 of HIV-l and p26 of HIV-2, said epitope located within amino acid residues 140-160 of p24.

2. The monoclonal antibody of claim 1 wherein said epitope is located within amino acid residues 142- 158 of p24.

3. The monoclonal antibody of claim 1 wherein said epitope is located within amino acid residues 144- 158 of p24.

4. The monoclonal antibody of claim 1 wherein said epitope comprises the amino acid sequence Ser-Pro- Arg-Thr-Leu-Asn-Ala-Trp-Val-Lys.

5. The monoclonal antibody of claim 1 wherein said epitope comprises the amino acid sequence His-X-X- X-Ser-Pro-Arg-Thr-Leu-Asn-Ala-Trp-Val-Lys-X wherein X is any amino acid compatible with biologic function.

6. A monoclonal antibody which reacts with an antigen comprising the amino acid sequence His-X-X-X-Ser- Pro-Arg-Thr-Leu-Asn-Ala-Trp-Val-Lys-X wherein X is any amino acid compatible with biologic function.

7. A monoclonal antibody which reacts with an antigen comprising the amino acid sequence Ser-Pro-Arg- Thr-Leu-Asn-Ala-Trp-Val-Lys.

8. An epitope comprising the amino acid sequence His- X-X-X-Ser-Pro-Arg-Thr-Leu-Asn-Ala-Trp-Val-Lys-X wherein X is any amino acid compatible with biologic function and with which the monoclonal antibody of claim 1 reacts.

9. An epitope comprising the amino acid sequence Ser- Pro-Arg-Thr-Leu-Asn-Ala-Trp-Val-Lys with which the monoclonal antibody of claim 1 reacts.

10. The amino acid sequence His-X-X-X-Ser-Pro-Arg-Thr- Leu-Asn-Ala-Trp-Val-Lys-X wherein X is any amino acid compatible with biologic function.

11. The amino acid sequence Ser-Pro-Arg-Thr-Leu-Asn- Ala-Trp-Val-Lys.

12. A diagnostic kit for detection of HIV-l and HIV-2 comprising at least one antibody which reacts with an antigen of HIV-l and a monoclonal antibody of claim 1.

13. The diagnostic kit of claim 12 wherein said antibody is a monoclonal antibody.

14. The diagnostic kit of claim 13 wherein the epitope of said antibody comprises the amino acid sequence Ser-Pro-Arg-Thr-Leu-Asn-Ala-Trp-Val-Lys.

15. The diagnostic kit of claim 14 which contains two monoclonal antibodies which react with an antigen of HIV-l.

16. The diagnostic kit of claim 15 wherein one of said monoclonal antibodies which react with an antigen of HIV-l binds with an epitope located within amino acid residues 142-209 of p24 and the second of said monoclonal antibodies which react with an antigen of HIV-l binds with an epitope located within amino acid residues 263-344 of p24.

17. A diagnostic kit for detection of HIV-l and HIV-2 comprising at least one antibody which react with an antigen of HIV-l and the monoclonal antibody of claim 6.

18. A diagnostic kit for detection of HIV-l and HIV-2 comprising at least one antibody which react with an antigen of HIV-l and the monoclonal antibody of claim 7.

19. A method for detection of HIV-l and HIV-2 antigens in a sample which comprises contacting said sample with at least one antibody which reacts with an antigen of HIV-l and the monoclonal antibody of claim 1, and measuring the formation of antigen- antibody complexes.

20. The method of claim 19 wherein said antibody is a monoclonal antibody.

21. The method of claim 20 wherein said epitope comprises the amino acid sequence Ser-Pro-Arg-Thr- Leu-Asn-Ala-Trp-Val-Lys.

22. The method of claim 21 which contains two monoclonal antibodies which react with an antigen of HIV-l.

23. The method of claim 22 wherein one of said monoclonal antibodies which react with an antigen of HIV-l binds with an epitope located within amino acid residues 142-209 of p24 and the second of said monoclonal antibodies which react with an antigen of HIV-l binds with an epitope located within amino acid residues 263-344 of p24.

24. A method for detection of HIV-l and HIV-2 antigens in a sample which comprises contacting said sample with at least one antibody which reacts with an antigen of HIV-l and the monoclonal antibody of claim 6, and measuring the formation of antigen- antibody complexes.

25. A method for detection of HIV-l and HIV-2 antigens in a sample which comprises contacting said sample with at least one antibody which reacts with an antigen of HIV-l and the monoclonal antibody of claim 7, and measuring the formation of antigen- antibody complexes.

26. A method for detection of HIV-l and HIV-2 antibodies in a sample which comprises contacting said sample with the epitope of claim 8 and measuring the formation of antigen-antibody complexes.

27. A method for detection of HIV-l and HIV-2 antibodies in a sample which comprises contacting said sample with the epitope of claim 9 and measuring the formation of antigen-antibody complexes.

28. A method for detection of HIV-l and HIV-2 antibodies in a sample which comprises contacting said sample with the amino acid sequence of claim 10 and measuring the formation of antigen-antibody complexes.

29. A method for detection of HIV-l and HIV-2 antibodies in a sample which comprises contacting said sample with the amino acid sequence of claim 11 and measuring the formation of antigen-antibody complexes.

30. A diagnostic kit for detection of HIV-l and HIV-2 antibodies in a sample comprising the epitope of claim 8.

31. A diagnostic kit for detection of HIV-l and HIV-2 antibodies in a sample comprising the epitope of claim 9.

32. A diagnostic kit for detection of HIV-l and HIV-2 antibodies in a sample comprising the amino acid sequence of claim 10.

33. A diagnostic kit for detection of HIV-l and HIV-2 antibodies in a sample comprising the amino acid sequence of claim 11.