EP0523056A1

EP0523056A1 - Neutralizing and/or adcc mediating monoclonal hiv antibody

Info

Publication number: EP0523056A1
Application number: EP91903427A
Authority: EP
Inventors: Britta Wahren; Per Anders Broliden; Bror Morein; Lennart Akerblom
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-01-31
Filing date: 1991-01-31
Publication date: 1993-01-20
Also published as: WO1991011198A1; SE9000333D0; AU7219891A; JPH05503851A; CA2073963A1

Abstract

L'invention concerne des anticorps monoclonaux (MAbs) contre le virus d'immunodéficience humaine (VIH) permettant la neutralisation du VIH et/ou une cytotoxicité dépendant de l'anticorps vis-à-vis des cellules infectées par le virus, ainsi qu'un procédé de préparation de ces MAbs et d'hybridomes produisant ces MAbs. Ces MAbs servent, entre autres, de vaccin passif ou actif, ainsi qu'à la prévention de la propagation des infections à VIH, à l'analyse d'antigènes VIH et à l'identification d'un épitope de neutralisation dans les préparations destinées à l'immunisation.The invention relates to monoclonal antibodies (MAbs) against the human immunodeficiency virus (HIV) allowing the neutralization of HIV and / or an antibody-dependent cytotoxicity with respect to cells infected with the virus, as well as a process for the preparation of these MAbs and of hybridomas producing these MAbs. These MAbs serve, among other things, as a passive or active vaccine, as well as for the prevention of the spread of HIV infections, for the analysis of HIV antigens and for the identification of a neutralization epitope in preparations intended for immunization.

Description

Neutralizing and/or ADCC mediating monoclonal HIV antibody.

This invention is concerned with monoclonal antibodies (MAbs) to human immunodeficiency virus (HIV), said MAbs mediating neutralization of HIV and/or antibody-dependent cellular cytotoxity to HIV.

Human immunodeficiency virus type 1 (HIV-1) induces a slowly progressive degeneration of the immune system. The most severe consequence of the immunological affection, the acquired immunodeficiency syndrome (AIDS), was first described in 1981 (Gottlieb et al., New Engl. J. Med. 305:1425, 1981).

During the search for the cause of AIDS, a novel retrovirus was isolated from a patient with lymphadenopathy in 1983, followed by large series of virus isolates from patients with, or at risk for AIDS (Barre-Sinoussi et al., Science 220:868, 1983; Gallo et al., Science 224:500, 1984). The virus was identified as a non-transforming cytolytic retrovirus.

The number of patients with the syndrome of immunodeficiency rapidly increases (Centers for Disease Control, MMWR 1983-89). AIDS cases were reported in increasing numbers mainly among homosexual (HS) men, among intravenous drug abusers and recipients of blood products. However, sexual transmission in the heterosexual population also increases. In 1983 it became apparent that AIDS was spreading among the heterosexual population in parts of Africa. AIDS is now recognized in all parts of the world and the number of AIDS cases reported to the World Health Organization (WHO) at the end of 1989 reached above 203.000 cases. More than 50% of these have already died from the disease and the number of reported cases is continuously increasing. The infection is now spreading worldwide, also affecting previously spared countries e.g. in Asia. The number of people already HlV-in- fected and expected to present themselves with AIDS in the future has been estimated at more than 3-10 millions.

HIV-1 seropositive individuals are often asymptomatic for several years whereas some patients rapidly progress to AIDS. Persistent generalized lymphadenopathy (PGL) is a common finding in HIV-1 infected individuals. The mortality among patients with opportunistic infections and immunodeficiency is high. All patients have immunological defects indicative of a depressed cell-mediated immunity. The most striking immunological abnormality is a nearly total absence of the CD4+ subset of T-lymphocytes (see Haseltine, J. AIDS 1:217, 1988). AIDS is the final stage of HIV-1 infection. An increasing proportion of HIV-1 infected individuals progress to AIDS over time and it has been estimated that approximately 30% of HIV-1 infected individuals will develop AIDS by seven years. AIDS can be preceded by a number of unspecific symptoms such as fatigue, diarrhoea, weight loss and fever. Viral or fungal infections of the skin or mucous membranes can also be seen in later stages of HIV-1 infection. In addition, HIV-1 can also infect the central nervous system causing neurological symptoms

(Navia et al., Ann. Neurol. 19:517, 1986). The long course of HIV-1 infection makes it important to intervene with the infection at an early stage. Development of antibodies with functional capacity to inhibit viral spread is one potent way of intervention.

Research within the field of HIV, and especially its final infection stage AIDS, has been intensive for the last decade. Nevertheless there is still a great need for improvements e g as regards HIV diagnosis and therapy. Protection against HIV infection, e g a vaccine, is of course highly desirable.

HIV virus belongs to the retroviruses which means that its genetic material is RNA. Different types and strains of HIV viruses, have been discovered. Thus, in addition to HIV type 1 (HIV-1), which is responsible for the main AIDS epidemic, an AIDS virus designated HIV-2, which is clearly related to HIV-1, has also been found. So although the present invention has been disclosed mainly with regard to HIV-1 and some strains thereof it is not limited to those particularly mentioned herein but relates to HIV virus in general.

It is known that HIV infection begins when HIV binds to a receptor molecule called CD4 on the target cell, usually a lymphocyte or a macrophage. Such binding takes place when CD4 interacts with a glycosylated protein of the HIV envelope called gp120. Thereafter, the virus particle enters the cell through endocytosis (including initially that the target cell membrane encloses the bound virus particle) or fusion, in which processes a second glycoprotein of the envelope, called gp 41, is involved.

These envelope proteins, gp120 and gp41 are f ormed through cleavage of a precursor glycoprotein, gp160

(Haseltine, J. AIDS 1:217, 1988). At the end of the replicative cycle of HIV, the processed viral proteins and genomic viral RNAs assemble at the cell membrane followed by a release of virus particles from the infected cell through budding. At that time the virus envelope protein gp120 is accessible to antibody neutralization whereby the binding of virus to CD4 on host cells is prevented. Besides, the infected cells are susceptible to antibody-dependent cellular cytotoxicity

(ADCC).

The outer envelope protein gp120 shows the most extensive variability among the HIV-1 proteins (Wong-Staal et al., Science 229:759, 1985). Nevertheless, alternate conserved and hypervariable regions have been shown to exist within the gp120. Within the gp120 encoding region, there are four hypervariable regions and five highly conserved regions. All cysteine residues have been shown to be conserved amongst all strains of HIV-1 suquenced to date which suggests a common threedimensional structure.

HIV-1 envelope proteins play a major role in the interaction with the receptor, induction of cytopathic effect and development of humoral and cellular immune responses. Some of the functional and immunogenic envelope sites have been mapped.

Obviously, it can be expected that monoclonal antibodies to these envelope proteins could be very useful in HIV infection treatment and diagnosis.

HIV type 1 (HIV-1)-specific neutralizing antibodies that are able to inhibit viral infection in vitro have been reported (Robert-Guroff, M., M. Brown, and R.C. Gallo, 1985. Naure (London) 316:72-74; Weiss, R.A., P. Clapham, J. Weber, R. Cheinsong-Popov, A. Dalgleish, A. Carne, I. Weller, and R. S. Tedder, 1985, Nature (London) 316:69-72), although the protective role of these antibodies against HIV infection in humans is controversial.

Several authors have reported that HIV-1-neut ral izing antibodies can be produced against various regions of gp120 (HO, D. D., J. C. Kaplan, I.E. Rackauskas, and M. E. Gurney, 1988, Science 239:1021-1023, Matsushita, S., M. Robert-Guroff, J. Rusche, A. Koito, T. Hattori, H. Hoshino, J. Javaherian, K. Takatsuki, and S. Putney, 1988, J. Virol, 62:2107-2114,

Palker, T. J., M. E. Clark, A. Langlois, T. J. Matthews, K. J.

Weinhold, R. R. Randall, D.I. Bolognesi, and B. F. Haynes, 1988, Proc. Natl. Acad. Sci. USA 85:1932-1936, Putney, S. D., T. J. Matthews, W.G. Robey, D. L. Lynn, M. Robert-Guroff, W. T.

Mueller, A. Langlois, J. Ghrayeb, S. R. Petteway, K.J.

Weinhold, P. J. Fischinger, F. Wong-Staal, R. C. Gallo, and D. P. Bolognesi, 1986, Science 234:1392-1395), gp41 (Kennedy, R. C, G. Dreesman, T. C. Chanh, R. Bowell, J.S. Allan, T. H. Lee, M. Essex, J. T. Sparrow, D. D. Ho, and P. Kanda, 1986, J. Biol.

Chem. 262:5769-5774), and p17 (Papsidero, L.D., M. Sheu, and F. W. Ruscetti, 1989, J. Virol. 63:267-272).

One major site inducing neutralizing antibodies has been described as a hypervariable loop of gp120 (Goudsmit, J., C. Debouck, R. Meloen, L. Smit, M. Bakker, D.M. Asher, A.V. Wolff, C. J. Gibbs, and D. C. Gajdusek, 1988, Proc. Natl. Acad. Sci USA 85:4478-4482, Rusche, J.A., K. Javaherian, C. McDanal, J. Petro, D. L. Lynn, R. Grimaila, A. Langlois, R.C. Gallo, L. O. Arthur, P. J. Fischinger, D. P. Bolognesi, S. Putney, and T. J. Matthews, 1988, Proc. Natl. Acad. Sci. USA 85:3198-3202).

Even though several neutralizing monoclonal antibodies

(MAbs) (Matsushita, S., M. Robert-Guroff, J. Rusche, A. Koito, T. Hattori, H. Hoshino, K. Javaherian, K. Takatsuki, and S. Putney, 1988, J. Virol. 62:2107-2114; Skinner, M. A., R. Ting, A. Langlois, K. J. Weinhold, K. Lyerly, K. Javaherian, and T. J. Matthews, 1988, AIDS Res. Hum. Retroviruses 4:187-197) have been produced, no MAb mediating ADCC was previously described.

Most of these reports are concerned with polyvalent rather than monoclonal antibodies, which have only virus-neut- ralizing capacity. Monoclonal antibodies that mediate both antibody-dependent cellular toxicity (ADCC) and neutralization have not been disclosed before.

The present invention is related to an intact or substantially intact monoclonal antibody or an idiotype-containing polypeptide portion thereof characterized in that it is reactive with human immunodeficiency virus (HIV) mediating neutralization of HIV and/or antibody-dependent cellular cytotoxicity to HIV.

According to a preferred embodiment the monoclonal antibody of the present invention mediates both neutralization and ADCC .

The HIV reactive monoclonal ant ibodies of the present invention are further characterized in that the antigenic determinants that are recognized by the monoclonal antibodies are epitope regions of the envelope proteins gp120, gp41 or P17.

According to a suitable embodiment the monoclonal antibodies are specific to HIV-1 being reactive with gp120 of HIV-1 and specifically with the epitopic X₁X₂QRGPGRX₃X₄ sequence of gp120, where X₁-X₄ are arbitrary amino acids, and preferably with the epitopic sequence GPGR of gp120.

The monoclonal antibodies of the present invention are of mammal origin. Preferably they are murine, specially mouse, monoclonal antibodies. The variable domains with the effective reactivity can also be introduced in a human Ig frame work (Riechman et al, Nature 332:323, 1988) or making chimeric antibodies with major human isotypes (Morrison et al, Proc. Natl. Acad. Sci. 81:6853, 1984, Boulianne et al, Nature

312:643, 1984, Neuberger et al, Nature 312:604, 1984).

A process of preparing the monoclonal antibodies of this invention includes in general immunizing a mammal, preferably a mouse, using HIV or a portion thereof, such as an envelope protein, e g gp120, as immunogen, producing hybrid-ic cells by fusion of lymphocytes, such as splenic cells from the immunized mouse with myeloma cells and selecting fused cells in a suitable medium (Köhler and Milstein, Nature 256:495, 1975), screening antibody producing cells in a solid phase enzyme -linked immunoassay (ELISA), cloning antibody producing cells i e hybridoma, and producing monoclonal antibodies in ascitic fluid of mice or in a culture medium by propagating the hybridoma therein.

The monoclonal antibodies of the present invention can be used as an active ingredient in a pharmaceutical composition for treating HIV infection and preventing spread of the infection, and is suitably used together with a physiologically tolerable diluent.

According to another aspect of this invention the present monoclonal antibodies can be used in a diagnostic system for assaying presence of HIV antigen, such as gp120 or a sequence therein, in a biological sample, e g blood or serum. In such systems an indication means may be included, which binds selectively with the antibodies, when introduced in the sample.

A further aspect of the invention is the use of monoclonal antibodies of the invention or portions thereof as an active or passive vaccine against HIV infection or as an immunogen to produce anti-idiotype antibodies.

Yet another aspect of the invention is the use of the present monoclonal antibody or a fraction thereof in a system to identify a neutralizing epitope e g as a quality check, in preparations used for immunization, such as vaccines.

The MAbs of the present invention are characterized by antibody-dependent cellular cytotoxity activity (ADCC) and/or neutralization capacity.

ADCC killing of virus-infected cells depends on effector cells with Fc receptors for immunoglobulin (Ig) which bind and kill Ig-coated target cells. Most ADCC killing in normal blood is mediated by natural killer (NK) cells which express a particular Fc receptor for IgG (Ljunggren et al., J. Immunol. Meth. 104:7, 1987). ADCC killing thus represents a combination of humoral adaptive and cellular nonadaptive immunity and is an important means of limiting the spread of virus infection.

Neither any monoclonal antibody with ADCC activity nor any active site for efficient ADCC reactivity has been previously described. Neutralizing antibodies against viral antigens have shown protective effects in patients infected with most viruses and in prevention of viral infection by prophylaxis and thus might have a similar beneficial effect on the clinical course of HIV infections. Antibodies adhere to the virions which thereafter are inactivated and do not show infectious properties to cells.

A number of neutralizing epitopes on HIV-1 gp120, gp41 and p17 have been defined. Of particular interest is an immunodominant loop in gp120, which has been shown to elicit type-specific neutralizing antibodies (Rusche et al., Proc. Natl. Acad. Sci. 85:3198, 1988; Goudsmit et al., AIDS 2:157, 1988).

There are several studies of polyclonal antisera raised in animals against different HIV-specific antigens. In

contrast to immunizations with synthetic peptides, which can raise neutralizing antibodies to several regions of gp120 and gp41, neutralizing antisera raised to disrupted virions, purified gp120 or recombinant products usually recognize one single region within the V3 domain. Three Mabs directed to the envelope gp120 of HIV-1 were shown to have neutralizing activity: One Mab is directed to a hypervariable site of the region Asn³⁰¹-L-Gly³¹² and hence it is easy to understand its type-specific neutralization pattern (Skinner et al., AIDS Res. Hum. Retroviruses 4:187, 1988). A second Mab also shows only type-specific reactivities. The epitope contains hypervariable sites (Matsushita et al., J. Virol. 62:2107, 1988). Thomas et al. (AIDS 2:25, 1988) describe several Mabs with neutralizing activities directed to gp120 without further specification.

In contrast, to these Mabs of prior art the cross-reactive Mabs of the invention are directed to conserved amino acids only, with a minimum of exchangeable amino acids.

In the illustrative examples the invent ion is disclosed with reference to suitable embodiments thereof but is not intended to be limited to those embodiments.

In these examples it is referred to the drawings where Figure 1 illustrates ADCC of two Mabs of the present inven tion, Figure 2 shows peptide blocking ELISA for two Mabs of the present invention and Figure 3 illustrates mapping of epitopes for different Mabs of the present invention.

Example 1. Antibody-dependent cellular cytotoxicitv (ADCC)

The ADCC assay was performed as described (Ljunggren et al., J. Immunol. Meth. 104:7, 1987). The monocytoid cell line U937, clone 2, continuously infected with HTLV-IIIB was used as target cell s . Peripheral blood mononuc lear cells ( PBMC ) obtained f rom HIV antibody negative blood donors were used as effector cells. The PBMC were collected by density centrifugation on Lymphoprep (Nykomed, Lidingö, Sweden) and adherent cells were removed by nylon wool. ⁵¹Cr-labelled target cells (1 x 10⁴) and lymphocytes as effector cells (2 x 10⁵) were mixed with dilutions of monoclonal antibodies prepared in Example 3. Supernatants were harvested after 3 hours and released radioactivity was calculated. The spontaneous release never exceeded 10%. HIV-antibody positive sera with known ADCC titers were included in the test. HIV specific ADCC was determined as follows: specific ⁵¹Cr-release with HIV-positive sera minus specific ⁵¹Cr-release with HIV-negative sera. The reciprocal of the last dilution step with an SAI-value (specific ADCC index) >0.5 was taken as the ADCC titer. This value represents more than 3 SD above the specific ^{5 1}Cr-re lease obtained by HIV-antibody negative sera. Figure 1 shows that of the Mabs prepared in Example 3 Mab P4/D10 has a clear ADCC reactivity, while Mab F58/H3 has no such reactivity.

Exemple 2. Neutralization (NT)

100 μl of virus supernatant (reverse transcriptase activity 80.000 CPM/ml) was preincubated for 60 min. at 37°C with serial dilutions of Mabs prepared in Example 3. The antibody-virus mixture was added to 1 x 10⁵ activated PBMC for 60 min. at 37°C. After washing three times, the cells were cultured for 6-8 days in RPMI-1640 medium supplemented by 10% fetal calf serum, 1% glutamine, 2.5 μg/ml polybren-e and antibiotics. Supernatants were collected after 4 and 8 days of incubation and analysed by HIV antigen determination. This is a measure of the capacity of Mab to inactivate HIV. Plates (Nunc, Roskilde, Denmark) were coated over night in room temperature with 20 μg/ml of anti-HIV immunoglobulin. 100 μl of supernatants were added to each well and incubated over night in room temperature. Two horse-radish peroxidase- -conjugated HIV antibodies reacting with different epitopes of HIV-p24 were used for antigen detection. The substrate ortho-phenylene amine was added and the absorbance was measured at 490 nm. Neutralization was defined as >90% reduction in the amount of p24 antigen in the supernatant as compared to 5 HIV seronegative controls. HIV antibody positive sera with known neutralization titers were included in each test. The values obtained are indicated in Table 1.

Example 3. Preparation of HIV-1 monoclonal antibodies:

The HIV envelope gp120 used as an immunogen was prepared from culture fluid of HIV-1 (HTLV-IIIB) infected H9 cells (Popovic, Science 224:497, 1984). NMRI mice (National Veterinary Institute, Uppsala, Sweden) were immunized on day zero with 10 μg gp120 in Freund complete adjuvant, and with four monthly immunizations of 5 μg gp120 in Freund incomplete adjuvant. Four days after the final immunization, splenic cells were fused with cells of the sp2/OxAg14 mouse myeloma cell line and selected in hypoxanthine-aminopterin-thymidin DMEM medium as described by Kdhler and Milstein (Nature

256:495, 1975). Individual wells were assayed for reactivity with viral antigen in a solid phase enzyme-linked immunosorbent assay (ELISA). Cells in positive wells were cloned by limiting dilution. Mabs were produced in ascitic fluid in pristane pretreated mice and lgG purified by DEAE Affigel Blue (BioRad, Richmond, CA.) chromatography. Many Mabs were produced by these fusions. Samples of two of the produced new hybridoma cell lines were deposited on January 16, 1990 in the PHLS Centre for Applied Microbiology & Research, European Collection of Animal cell culture, Salisbury, Great Britain with the accession numbers ECACC 90011607 and 90011608 for the Mabs of the present invention designated F58/H3 and P4/D10, respectively. Example 4. Characterization OF Mabs directed to the HIV-1 envelope antigens.

Six HIV-1 anti-gp120 Mabs from Example 3 having neutralizing activity and one the additional unexpected property of ADCC activity as well were assayed for reactivity to HIV-1 proteins (Table 1). The titers were similar against recombinant gp160 and pB1 with six Mabs. In Western blot analysis the Mabs showed reactivity to gp160 and gp120. In immunofluorescence, positive reactions to HIV-1 infected cells and negative reactions with uninfected cells were seen with seven of all six Mabs directed to HIV-1 gp120.

The six Mabs had neutralizing properties to HIV strain- HTLV-IIIB varying between titers 100 to 1000 (Table 1). The neutralizing titers were similar in different target cells. Neutralization to another HIV strain called B23 is shown in Table 2.

By competitive inhibition, unlabelled Mabs displaced labelled ones, in distinct groups. All six Mabs with neutralizing activity belonged to one group.

Example 5. Analysis of epitopes with peptides.

For more specific epitope mapping of the gp120 region, 15aa peptides covering the gp120 region were used. All eight gp120-directed Mabs from Example 3 reacted with peptides in solid phase (Table 3).

The direct peptide ELISA reactions shown in Table 3 were performed with 1 μg/ml of antigen for coating, incubation with 1-100 ng/100 μl of antisera for 60 min. at 37°C and horseradish peroxidase (HRP)-rabbit antimouse-Ig conjugate

(Dakopatts, Copenhagen, Denmark). The substrates were ortho- phenylenediamine (OPD) or tetramethylbenzidine (TMB). The absorbances were read at 490 nm (OPD) or 450 nm (TMB). An absorbance value (A) of 0.2 was used as the cut-off value (means of negative sample absorbance plus two standard deviations). Six Mabs reacted with high absorbance. in the direct assay with peptide aa 304-318 and more weakly with peptide aa 309-323. The common overlapping amino acid sequence of those two peptides was IQRGPGRAFV. These six Mabs did not display reactivity with any other envelope-representing peptide. Peptide blocking ELISA shown in Table 3 and Figure 2 was performed with Mabs at a dilution giving an absorbance at A490 nm of 1.0-1.5. A final concentration of 0.5 μg/ml of peptide was incubated with an equal volume of diluted Mab for 60 min. at 37°C. 100 μl of this mixture was transferred to a coated plate (recombinant pB1 or gp160) and incubated for 60 min. at 37°C. The detection systems mentioned above were applied.

Mabs (D59/A2, F58/H3, P1/D12 and P4/D10) were all inhibited with peptides aa 304-318 and 309-323. Mab A47/B1 and G44/H7 were inhibited by peptide 304-318 only (Table 3 and Fig. 2).

Fine mapping of the region that appeared to be dominant for the neutralizing Mabs was performed. 8aa peptide sequences with a 7aa overlap were synthesized for eight HIV-1 s t rains reported in the Database (Myers, Database on Human Retroviruses and AIDS, Los Alamos Natl. Lab., Los Alamos). This was done in order to establish the sequence important for ADCC and neutralization. Figure 3 shows that the sequence QRGPGR is necessary for antibody reactivity. In addition P4/D10 and F58/H3 were reactive with peptide sequences representing several HIV strains (Fig. 3). This implies that these monoclonal antibodies will be effective in treating patients (passive immunoprofylaxis) with HIV infection. The sequence of HIV strain HTLV-IIIB to which the Mabs were produced is shown in Figure 3. All six neutralizing Mabs were strongly dependent on the motif GPG and the two Mabs with the highest NT titers depended on QRGPGR.

The NT Mabs reacted with the central sequences o f othe r H IV-1 isolates in a varying manner (Fig. 3). Sequences of HIV strains MN, RF, NY5, CDC4 and BRVA mediated strong reactivities. The epitopic reactivities of Mabs with neutralizing capacity could be narrowed down to a sequence of QRGPGR for HIV strain HTLV-IIIB.

In addition the described HIV-1 region induces ADCC activity. Although the entire region is variable, the sequence to which our neutralizing and ADCC-active Mab P4/D10 was directed is highly conserved between isolates. It is of interest to note, that the broad serological reactivity of our Mabs, especially the high-titered P4/D10 and F58/H3, indicates a group-specific reactivity. This differs from the type-specific neutralization of Mabs to other HIV peptides.

The unexpected property of both neutralizing capacity and ADCC effect in one Mab is shown in Table 1. The detailed ADCC reactivities of two monoclonals is shown in Figure 1. Thus Mab P4/D10 has both NT and ADCC activity while five other Mabs have only neutralizing activity.

In the descript ion of the present invention the conventional one letter code for amino acids has been used. This code as well as the common 3 letters abbreviations are explained below.

Amino acids Abbreviation

Alanine Ala A

Cysteine Cys C

Aspartic acid Asp D

Glutamic acid Glu E

Phenylalanine Phe F

Glycine Gly G

Histidine His H

Isoleucine Ile I

Lysine Lys K

Leucine Leu L

Methionine Met M

Asparagine Asn N

Proline Pro P

Glutamine Gin Q

Arginine Arg R

Serine Ser S

Threonine Thr T

Valine Val V

Tryptophane Trp W

Tyrosine Tyr Y

Table 2. Neutralization of HIV strain B23.

Values above 1.0 indicate no neutralization, values below 1.0 indicate neutralization.

Claims

CLA I MS 1. An intact or substantially intact monoclonal antibody or an idiotype-containing polypeptide portion thereof characterized in that it is reactive with human immunodeficiency virus (HIV) mediating neutralization of HIV and/or antibody- -dependent cellular cytotoxicity to HIV.

2. A monoclonal antibody or portion thereof according to claim 1, characterized in that it mediates neutralization of HIV in combination with antibody-dependent cellular cytotoxicity to HIV.

3. A monoclonal antibody or portion thereof according to claim 1 or 2 characterized in that it is of mammal origin and preferably it is a murine, such as mouse, monoclonal antibody or portion thereof or combined with human frame work.

4. A monoclonal antibody or portion thereof according to claim 1, 2 or 3, characterized in that it is reactive with HIV type 1 including the HIV strains MN, RF, NY5 , CDC4, BRVA and/or HTLV-IIIB.

5 . A monoc lonal ant ibody or portion thereo f according to any of claims 1-4, characterized in that it is reactive with a glycosylated protein, gp120, in the HIV envelope, and suitably with a peptide sequence X₁X₂QRGPGRX₃X₄ of gp120, where X₁, X₂, X₃ and X₄ each is an arbitrary amino acid, or with a peptide sequence GPGR of gp120.

6. A monoclonal antibody or portion thereof according to any of claims 1-5, characterized in that said antibody is produced by a hybridoma formed by fusion of a myeloma line and lymphocytes, such as splenocytes, that produce antibodies that react with HIV, eg HIV gp120, from a mammal, such as mouse immunized with an HIV immunogen such as an HIV gp120-containing immunogen, wherein said hybridoma is hybridoma ECACC accession number 90011607 or ECACC accession number 90011608.

7. Hybridoma that can produce a monoclonal antibody according to claim 1, characterized in that said hybridoma is hybridoma ECACC accession number 90011607 or hybridoma ECACC accession number 90011608.

8. A method of preparing a monoclonal antibody or portion thereof according to any of claims 1-6, characterized by propagating the hybridoms ECACC accession number 90011607 and 90011608, respectively, in mice or culture medium and recovering the monoclonal antibody or portion thereof from ascitic fluid of the mice, or from the culture medium.

9. A composition for preventing spread of HIV infection characterized in that it comprises an effective amount of a monoclonal antibody or portion thereof according to any of claims 1-6 and a physiologically tolerable diluent.

10. A diagnostic system for assaying presence of HIV antigen, such as gp120, in a biological sample, characterized in that it comprises as an active component a monoclonal antibody or portion thereof according to any of claims 1-6, and optionally an indicating means, that when introduced into a sample, binds selectively with said antibody or portion thereof.

11. Use of a monoclonal antibody or portion thereof according to any of claims 1-6 as an active or passive vaccine against HIV infection or as immunogen to produce ant i- idiotype antibodies.

12. Use of a monoclonal antibody or portion thereof according to any of claims 1-6 in a system to identify a neutralizing epitope, e g as a quality check, in preparations used for immunization, such as vaccines.