WO1990004978A1 - Methode pour diriger une reponse immunitaire vers un site de liaison viral - Google Patents

Methode pour diriger une reponse immunitaire vers un site de liaison viral Download PDF

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Publication number
WO1990004978A1
WO1990004978A1 PCT/US1988/003886 US8803886W WO9004978A1 WO 1990004978 A1 WO1990004978 A1 WO 1990004978A1 US 8803886 W US8803886 W US 8803886W WO 9004978 A1 WO9004978 A1 WO 9004978A1
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antibodies
binding
hiv
virus
cells
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PCT/US1988/003886
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English (en)
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Tran C. Chanh
Ronald C. Kennedy
Vernon C. Maino
Noel Warner
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Becton Dickinson And Company
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Priority to PCT/US1988/003886 priority Critical patent/WO1990004978A1/fr
Publication of WO1990004978A1 publication Critical patent/WO1990004978A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K16/00—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies
    • C07K16/18—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans
    • C07K16/28—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants
    • C07K16/2803—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants against the immunoglobulin superfamily
    • C07K16/2812—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants against the immunoglobulin superfamily against CD4
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K39/00—Medicinal preparations containing antigens or antibodies

Definitions

  • This invention is related to the use of antibodies as immunogens and is particularly directed to the use of anti-CD4 antibodies as immunogens to direct an immune response against the HIV virus.
  • AIDS Acquired Immune Deficiency Syndrome
  • LAV human T lymphotrophic retrovirus
  • HTLV- III human immunodeficiency virus
  • HIV-1 human immunodeficiency virus
  • This and other HIV isolates (such as HIV-2), infect, replicate in, and are) cytopathic for T cells with the helper/inducer phenotype that is defined by the presence of the CD4 antigen.
  • Infection with the AIDS virus can result in a progressive depletion of CD4 + T cells that eventually leaves the patient susceptible to opportunistic infections and/or malignancies that are the clinical manifestations of AIDS.
  • CD4 the CD4 molecule on the surface of -the T helper/inducer cells functions as a receptor for HIV. It has recently been shown that the HIV interaction with CDM occurs via an envelope glycoprotein having a molecular weight of 110,000-120,000 known as gp120 (also referred to in some publications as gp110 because of its variable molecular weight).
  • gp120 envelope glycoprotein having a molecular weight of 110,000-120,000 known as gp120 (also referred to in some publications as gp110 because of its variable molecular weight).
  • the gp120 molecule is the larger subunit of the gpl ⁇ O envelope protein of HIV which, upon maturation of the virus, is processed into an exterior 120 kd subunit (gp120) and a smaller transmembrane 41 kd subunit (gp41).
  • the CD4 antigen on T lymphocytes has been characterized as being a 60,000 Dalton protein expressed on approximately 65% of human peripheral blood T lymphocytes.
  • the antigen is often defined by its ability to react with monoclonal antibodies, specifically the Leu3a monoclonal antibody manufactured by Becton- Dickinson.
  • Antibodies reactive with the same protein molecule are 0KT4 and 0KT4a, manufactured by Ortho, and anti-T4, manufactured by Coulter, Inc.
  • anti-CD4 antibodies production from anti-CD4 antibodies of an effective neutralizing anti-idiotypic antibody against HIV has proven difficult.
  • a study of four candidate anti-CD4 monoclonal antibodies that were potent inhibitors of virus binding (0KT4a, 0KT4d, 0KT4f, and Leu3a) attempted to use these individual monoclonal antibodies to produce anti-idiotypic sera in rabbits that would bind to HIV-1.
  • the anti-idiotypic sera raised against each of the four candidate CD4 monoclonal antibodies did not react with virus nor in- hibit virus binding to CD4 + T cells.
  • McDougal et al., J. Immunol. (1986) 137:2937-2944 describes the binding of HIV to the CD4 molecule and the production of rabbit-anti-idiotypic sera raised against anti-CD4 monoclonal antibodies. Chanh et al., Proc. Natl. Acad. Sci. USA (1987) 84: 3891-3895 describes a monoclonal anti-idiotypic antibody capable of mimicking the CD4 receptor and binding HIV. Fingeroth et al., Proc. Natl. Acad. Sci. USA (1984) 81: 4510 describes the receptor for Epstein-Barr virus (EBV).
  • EBV Epstein-Barr virus
  • the present invention provides a method of directing an immune response to a specific viral binding site.
  • the method provides a collection of antibodies that can be used as an immunogen, for example to produce a diagnostic antiserum or as a vaccine.
  • binding of HIV particles to human cells can be prevented by inducing an immune response in human cells to a plurality of gp120-internal-image anti-CD4 antibodies of different specificities.
  • antibodies against the gp120-internal- image anti-CD4 antibodies will be produced that are capable of binding the gp120 antigen and neutralizing HIV infection.
  • gp120-internal-image anti-CD4 antibodies By providing a plurality of different specificities in the gp120-internal-image anti-CD4 antibodies presented to the human B cells, a broad immune response occurs which is better able to neutralize polymorphic HIV viruses.
  • the plurality of gp120- internal-image anti-CD4 antibodies could alternately be used to produce a diagnostic antiserum capable of detecting the presence of HIV. Similar antibody collections can be prepared to other viruses if the binding site on the virus and the receptor on the host cell are known.
  • the present invention provides a method of preparing a collection of antibodies that can be used as a vaccine against a viral infection, such as acquired immune deficiency syndrome (AIDS), or can be used to prepare an antiserum used to diagnose the presence of infective viral particles.
  • a viral infection such as acquired immune deficiency syndrome (AIDS)
  • AIDS acquired immune deficiency syndrome
  • the immunogenic preparation described in this disclosure is not based on the virus itself or on virus- derived materials. Nor need any viral substance be manufactured or administered to human subjects. Instead the composition is generated by a selection procedure applied to antibodies prepared using the viral receptor as an immunogen.
  • the composition contains a collection .of monoclonal antibodies of different specificities that are reactive with the viral receptor, such as HIV-reactive epitope(s) on the CD4 antigen molecule found on the cell surface of T helper lymphocytes.
  • a collection of antibodies is obtained that is capable of eliciting an immune re- sponse to provide an antiserum or cell mediated response that reacts with the viral binding site; i.e., the immune response produces receptor-like anti-idio- typic antibodies.
  • the collection of antibodies is therefore useful either as a vaccine or as an agent for inducing an antiserum used in diagnosis or for other purposes.
  • the three selection procedures are carried out on monoclonal antibodies (referred to as the source collection of antibodies) produced using the receptor for the virus as an immunogen.
  • monoclonal antibodies can be prepared by any suitable technique, such as innoculating an animal with a cell having a virus- specific receptor on its surface, carrying out an in vitro or in vivo immunization using a purified viral receptor, or any other technique for inducing antibody formation to the receptor molecule.
  • the source collection is prepared using a crude receptor preparation (such as a whole-cell or a cell-membrane preparation) as the immunogen, an initial screening is usually necessary to identify antibodies reactive with the receptor, as opposed to antibodies induced by other immunogens.
  • antibodies that are known to bind specifically to the receptor are known, such as the Leu 3a antibody discussed above. If the receptor is not known, it should be identified (characterization by binding to specific antibodies is sufficient for this purpose) in order to identify the source collection of antibodies.
  • known receptors for viruses are the CD4 receptor for HIV discussed above and the 03d receptor (also known as CR2 or CD21) for Epstein-Barr virus (EBV). The method can be applied to these or other known receptors or can be applied to currently unknown virus receptors as they are discovered.
  • the first key step of the present invention is to select monoclonal antibodies from the source collection that react with the binding site on the receptor that interacts with the virus particle. Such antibodies can be detected by their ability to interfere with the binding of viral particles (or the viral coat protein or other protein known to interact with the receptor) with the receptor. The resulting antibodies are referred to as virus-blocking antibodies and represent a first collection on which later selection techniques can be carried out.
  • the second selection is to obtain from the virus-blocking antibodies those antibodies that are capable of inducing an immune response that cross- reacts with the virus.
  • the first anti- body (Ab1) induces production of a second antibody
  • Ab2 also known as the anti-idiotypic antibody (anti- id), which reacts with the virus. Since Ab2 reacts both with Ab1 and the virus, Ab1 and the virus have similar binding sites, and Ab1 is referred to as having a viral internal image.
  • Ab1 If an Ab1 collection is eventually to be used as a vaccine, it is preferred to use the host organism or a closely related species to raise Ab2, since different organisms can respond differently to the same immunogen (here Ab1). Thus, if Ab1 is being tested for possible use in a human vaccine, Ab1 should either be innoculated into a human (or a non-human primate, for ethical reasons) or an in vitro human immune response should be elicited in order to provide the best possible guidance in selecting immunogenically active antibodies.
  • any active immune system can be used to generate Ab2, and even when Ab1 will be used In a vaccine, the system used to generate Ab2 is not required to be the host system.
  • the binding of Ab2 to the viral particles (or the purified surface protein or other component known to react with the receptor) can be carried using any technique that determines the binding of an antibody to an antigen. Examples include competitive reactions in which Ab2 interferes with the binding between a purified receptor and a purified viral protein, a host cell and a whole virus, or a combination of purified components and cells or viruses.
  • the final product composition of the present invention is a mixture of antibodies selected by the two procedures set forth above which have different specificities. Such antibodies, bind to slightly different locations on the receptor and induce formation of antibodies that interact with slightly different locations at or near the binding site on the virus particle.
  • the preparation of antibodies and selection procedure is described in connection with HIV and its receptor CD4.
  • the detailed description which follows can be applied to the preparation of an antibody collection for use as a vaccine or diagnostic antigen when the receptor that interacts with the virus is known.
  • Ab1 antibodies are prepared against the CD4 antigen.
  • Either purified CD4 antigen, a crude preparation of the antigen, or cells known to present CD4 antigen on their surface can be used as the immunizing agent since the selection process will eliminate antibodies of other specificities.
  • the amount of screening that must be done can be minimized by using a purified CD4 preparation as the immunogen.
  • Anti-CD4 monoclonal antibodies are obtained using standard techniques.
  • an anti-CD4 monoclonal antibody of the invention must be capable of blocking HIV binding to CD4.
  • blocking of HIV binding to CD4 is itself insufficient to define an antibody of the invention, since, as indicated in the background section, monoclonal antibodies capable of blocking HIV binding have previously been known which were incapable of inducing an immune response to provide the desired protective effect.
  • HIV-blocking anti-CD4 monoclonal antibodies must then be subjected to a selection procedure in which the HIV-blocking anti-CD4 monoclonal antibodies (Ab1) are used to induce anti- idiotype antibodies (Ab2).
  • the ability of the resulting-anti-id antibodies to bind with the gp120 envelope protein from HIV is then determined. If the HIV- blocking anti-CD4 monoclonal antibody induces an anti- idiotypic antibody reactive with the gp120 envelope protein, it is considered to have an internal image of the gp120 envelope protein and is a candidate for use in preparing the antibody collection of the invention. Such antibodies are referred to as gp120-internal-image anti-CD4 antibodies. However, a further selection remains to be made before a collection of antibodies suitable for practice of the present invention is designated. The collection must contain a plurality of gp120-internal- image anti-CD4 antibodies with different specificities.
  • an immune response is generated in the challenged host that is better able to neutralize an HIV infection than would be possible by challenge with a single gp120-internal- image anti-CD4 monoclonal antibody.
  • an antiserum is being prepared for a diagnostic test, a broad response range will be obtained.
  • the Ab1 collection of Gp120-internal-image anti-CD4 monoclonal antibodies will also be useful as an HIV mimic for a control sample that will not require use of active virus particles.
  • the present invention arises as a result of extension of the original characterization of CD4 epitopes using a new and large panel of monoclonal anti-CD4 antibodies . generated in the laboratories of the inventors. Initial characterization of these antibodies is shown in a table in the examples which
  • a superior collection of Ab1 monoclonal anti- bodies to be used for active immunization protocols, to generate antisera, or to mimic viral particles can be selected on the basis of the following criteria: (1) antibodies that demonstrate the most effective blocking of HIV infection as determined by syncytia formation, fluorescence binding assays, and blocking of reverse transcriptase activity during HIV infection of susceptible human cell lines and (2) antibodies within group (1) antibodies capable of eliciting strong HIV-reactive, neutralizing anti-idiotypic responses, particular in human systems if the Ab1 collection is to be used as a vaccine.
  • Neutralizing can be measured in vitro by measuring reduction of either viral reverse transcriptase activity or syncytia formation; analyses for both conditions are well known in the art.
  • a gp120-internal- image anti-CD4 preparation which induces a neutralizing anti-idiotypic response should inactivate divergent HIV isolates.
  • SIV simian immunodeficiency virus
  • the individual assays used in selection steps in preparing the indicated collection of antibodies are not limited to particular types of assay but can be any assay which demonstrates the required property (such as blocking of virus binding). Many such assays are now known and numerous others will doubtless be rapidly developed because of the continuous research and development being carried out in the HIV field and other areas of virus research. Several procedures are generally described below and references are given in order to provide guidance in achieving the proper selection of antibodies.
  • Anti-CD4 monoclonal antibodies can be produced by standard techniques.
  • the anti-CD4 monoclonal antibodies can be obtained from any species or can be a chimeric antibody of the type described in Morrison et al., Proc. Natl. Acad. Sci. USA (1984) 81 :6851-6855.
  • mice can be immunized intraperitoneally or intravenously with CD4 + cells.
  • CD4 + cells include the myelomonocytic cell line U937, the acute lymphocytic leukemia (ALL) cell line HPB-ALL, and the CD4-transfected (EL4) mouse cell line 119-16S2.
  • a typical immunization consists of a series of inoculations over several days prior to isolation and fusion of splenocytes.
  • Numerous fusion partners can be used, such as the mouse fusion partner SP2/o/Agl4.
  • Viable fused cells prepared by polyethylene glycol-mediated fusion or other fusion techniques, are initially screened for reactivity with CD4 + cells or purified preparations of CD4 antigen.
  • Monoclonal hybridomas are prepared from anti-CD4 producers, and their antibodies purified by standard techniques, such as affinity chromatography.
  • anti-CD4 antibodies are then subjected to a procedure which selects for blocking of HIV binding to the CD4 receptor.
  • One such method involves the inhibition of binding of labeled HIV particle to CD4 + cells as measured by flow cytometry.
  • antibodies which block the binding of purified or recombinant gp120 to CD4 + cells can be selected as virus-blocking antibodies.
  • HIV-blocking anti-CD4 monoclonal antibodies Once HIV-blocking anti-CD4 monoclonal antibodies have been selected, the resulting collection is again treated to select for gp120-internal-images-.
  • This selection will typically be carried out by generating anti-idiotypic antibodies in vivo or in vitro followed by determining the ability of the thus-produced anti-id antibodies to react with HIV or gp120.
  • a typical immunization would be carried out as described above.
  • Anti-id antibodies would then be incubated in vitro with HIV to determine if the anti-id antibody is capable of binding to and/or neutralizing the virus.
  • Procedures can also be carried out to determine if the resulting anti-id recognizes the gp120 envelope protein, such as the well known Western blot analysis.
  • the treated HIV is added to CD4 + cells.
  • aliquots of culture fluids are removed and reverse transcriptase activity determined by standard methods. Comparison of reverse transcriptase activity to controls will allow determination of whether infection of cells in in- hibited.
  • gp120-internal-image anti-CD4 antibodies Once gp120-internal-image anti-CD4 antibodies have been selected, they are combined to produce an effective immunogenic preparation of the invention.
  • one technique for selecting different specificities is to select antibodies having a different variable region amino acid sequence.
  • any characteristic that indicates a difference in specificity can be used to select the collection of antibodies.
  • epitope mapping and/or differences in reactivity with CD4 antigens can also be used to select a plurality of the desired antibodies.
  • chimeric human/mouse CD4 molecules can be generated and used to detect difference in binding of the anti-CD4 antibodies.
  • CD4 and L3T4 cDNA gene segments can be cloned and transformed simultaneously into a bacterial host where homologous recombination events can occur.
  • a series of CD4/L3T4 and L3T4/CD4 recombinants have been generated. Each of these recombinants have a short human segment in a mouse receptor molecule, the human segment appearing at different locations in the different molecules.
  • recombinant molecules can be used to measure both anti-CD4 reactivity and HIV-I binding.
  • the recombinant molecules themselves can be used as immunogens to produce dupl i cat e Ab 1 ant i bodi es of ident i cal s peci f i c i ti es when injected into mice, since only the human segment of the recombinant molecule will be immunogenic.
  • An additional embodiment of this invention is the therapeutic use of the proposed collection of anti- bodies in the treatment of AIDS. Since the response to this preparation would be an active immune response against the HIV binding site, the Ab1 collection can be used for therapy in AIDS as an active immunization to induce the anti-id response. However, patients who already have the disease and would therefore be the group considered for therapy have by definition a compromised immune system and therefore may not be able to mount an effective anti-id response against an Ab1 panel. This patient group is characteristically unable to make good immune responses against neo-antigens. However, their ability to mount a good response against previously sensitized antigens as carriers is not severely impaired.
  • the Ab1 panel will be conjugated by standard chemical means to immunogens (preferably protein in nature) to which the patient has been previously sensitized.
  • immunogens are generally known as carrieradjuvants.
  • carrier adjuvants include diptheria, pertussis and tetanus toxoid (DPT).
  • DPT diptheria, pertussis and tetanus toxoid
  • Techniques for attaching immunogens to carrier proteins are well known and are described in detail in the scientific literature. See, for example, Burdon and Knippenberg, eds., Laboratory Techniques in Biochemistry and Molecular Biology, Elsevier, pp. 221-241, for a review of macromolecular conjugation.
  • This mixture will be administered in an acceptable adjuvant form, preferably as an alum precipitate.
  • mice Female Balb/a mice were immunized intraperitoneally (I/P) or intravenously (I/V) with CD4 + cells. These CD4 + cells included PHA or ConA activated (CD8 depleted) peripheral blood lymphocytes, the myelomono- cytic cell line U937, the acute lymphocytic leukemia (ALL) cell line HPB-ALL, and the CD4 transfected (EL4) mouse cell line, 119-16S2. Generally, the immunization scheme consisted of 2-5 I/P inoculations of 10' cells, followed by an I/V dose of 5x10° cells three days prior to fusion.
  • I/P intraperitoneally
  • I/V intravenously
  • Immune splenocytes were fused to the non- secreting mouse fusion partner SP2/o/Ag14 using a modified polyethylene glycol mediated-fusion protocol.
  • the primary screen usually at 7-10 days post fusion, was performed on a Pandex Screen Machine, using a method Particle Concentration Fluorescence Immunoassay (PCFIA) adapted for viable cells.
  • PCFIA Particle Concentration Fluorescence Immunoassay
  • Hybrid supernates were assayed against CD4 + and CD4 " cell lines (HPB-ALL and LB respectively).
  • Antibody-containing supernates from the primary screens which reacted in an appropriate fashion were then subjected to single-color FACS analysis on peripheral blood mononuclear cells.
  • CD4 specific antibodies could be recognized by their characteristic staining pattern and the percentage of cells stained.
  • CD4 specific antibodies were purified as outlined above, and FITC conjugates of each prepared.
  • L83 and L88 Two apparently unique CD4 epitopes are represented by the antibodies L83 and L88.
  • L83 is unusual in that it does not block the binding of any other CD4 antibody conjugate, and blocking of L83 FITC conjugate can only be achieved by incubating cells with cold unlabeled L83.
  • L88 The reverse is true of L88, in that only L83 fails to block L88 FITC, and unlabeled L88 blocks all anti-CD4 FITC conjugates except L83.
  • al changes in the CD4 molecule can be induced by binding of antibody to a specific epitope on the CD4 molecule.
  • Cynomologus monkey cells do not stain positively with FITC conjugates of L34. L80, L69, or L88, i.e., the epitopes recognized by these antibodies are not expressed. However, monkey cells will stain positively with these FITC conjugates after pretreatment with cold L83, indicating that L83 binding results in a refolding of the protein molecule with subsequent expression of previously hidden epitopes.
  • the CD4 and L3T4 cDNA (Maddon et al., Cell (1986) 42:93; Littman et al., Proc. Natl. Acad. Sci. USA (1983) 80:3968) gene segments are cloned into a separate trpB defective plasraid.
  • these plasmids are transformed simultaneously into a trpB negative bacterial host, two homologous recombination events canoccur.
  • the first detectable event is in the trpB region, generating a functional trpB gene and allowing growth on selection media.
  • the second event is in the only other homologous region of the two plasmids, in the CD4 and L3T4 gene segments.
  • the second event is detected by altered size mobility of plasmid DNA in agarose gels and by antibiotic resistance patterns of plasmid containing bacterial colonies.
  • a series of nested CD4/L3T4 and L3T4/CD4 recombinants can be generated. The exact site of recombination can be mapped easily using restriction enzyme analyses followed by dideoxy sequencing of the appropriate DNA fragment.
  • Transfection of the recombinant cDNA into L3T4 negative murine cells will provide cells expressing the chimeric protein which can be tested for the presence of both anti-CD4 reactivity and HIV-1 binding.
  • One of the parameters to evaluate anti-CD4 antibodies, to determine which idiotypes (V region sequence) should be used in an immunogenic Ab1 vaccine preparation, is to measure the capacity of anti-CD4 antibodies to block HIV binding to its receptor.
  • a method used to define those antibodies that block HIV binding is to measure the inhibition of fluorochrome-conjugated (FITC or phycoerythrin) HIV binding to CD4 + cells by flow cytometry. This analysis has been conducted using flow cytometry with fluorescent conjugates of isolated heat inactivated HIV as described by Achour et al., Ann. Inst. Pasteur (1986)
  • This assay has been shown to be specific and enables the identification of HIV susceptible cells. It can also be used to characterize further the viral receptors from these cells.
  • the panel of anti-CD4 monoclonal antibodies described can be evaluated for their ability to block binding of HIV.
  • the antibodies which demonstrate the most effective HIV blocking activity will be further evaluated for their ability to block other parameters of HIV infection, including syncytia formation and reverse transcriptase activity.
  • anti-CD4 antibodies can be assessed by their ability to block binding of purified or recombinant gp120 to CD4 + cells. Binding of gp120 to CD4 + cells can be measured with either 1 25 I labeled gp120 in a direct binding assay or bound gp120 will be detected using a 125 I labeled anti-gp120 antibody and binding quantitated using a gamma counter. 125 l-BSA or irrelevant immunoglobulin can be employed as a non-specific control and specific binding will be assessed. For these studies, CD4 + cell lines, including CEM, HPB-ALL, and HUT-78 will be evaluated for gp120 binding. Anti- CD4 antibodies can be titrated against a concentration of gp120 which produces 50% maximal binding.
  • Titration curves generated from the resulting data will be used to compare relative efficacy of the anti-CD4 antibodies to block specific gp120 binding. These studies will employ similar cell and virus concentrations described by McDougal et al., J. Immunol. (1986) 137:2937-2944.
  • Incubation of gp120 with CD4 + cells will be performed at 37°C for 30 minutes.
  • immunoprecipitation will be performed following cross- linking of the labeled gp120/CD4 complex with dithiobis(succinimidyl)propionate, a chemical cross-linker that can be cleaved under reducing conditions.
  • the complexes are evaluated by polyacrylamide gel electro- phoresis (PAGE).
  • This analysis will allow direct assessment of the capacity of various anti-CD4 monoclonal antibodies to block gp120 binding. Specific blocking of the binding site by anti-CD4 monoclonal antibodies should result in a reduction in the amount of identified gp120.
  • the anti-CD4 monoclonal antibodies also will be evaluated for their ability to precipitate the cross-linked complexes. Those antibodies capable of precipitating the cross-linked complexes can be mapped outside the gp120 binding region of CD4 since the binding of gp120 would have no effect on the accessibility of their epitopes.
  • Binding studies with gp120 also can be performed with fluorescent-conjugated preparations of this protein using either fluorescein (FITC) or phycoerythrin (PE) derivatives. Binding of gp120 to CD4 + cells and inhibition of binding by anti-CD4 antibodies will be evaluated using flow cytometry (FACS). Preparation of fluorescent conjugates will be performed by standard methods. Blocking studies can also be performed in the reverse direction; preparations of purified gp120 can be evaluated for inhibition of fluorescent-conjugated anti-CD4 antibodies. These studies will be conducted only with those antibodies that demonstrate inhibition of gp120 binding since the amount of available gp120 is likely to be limiting.
  • FITC fluorescein
  • PE phycoerythrin
  • the HTLV-III ELISA (Electro-Nucleonics, Inc., Silver Spring, MD) and the LAV EIA (Genetic Systems, Seattle, WA) are carried out according to the manufacturers' specifications.
  • Horse radish peroxidase-goat anti-mouse IgG antibodies (Vector Laboratories, Burlingame, CA) can be substituted for the goat anti-human IgG enzyme conjugate.
  • the ELISA using psoralen and UV- inactivated HIV-1 can be done as described previously (16).
  • culture supernate from 7 day HIV (HTLV- IIIB) infected A3.01 cells are concentrated 10-fold and inactivated by exposure (three times) to psoralen (Calbiochem, San Diego, CA) at a final concentration of 10 ⁇ g/ml and UV light (360 nm) for 15 minutes.
  • the inactivated HIV is passed over a column of Sepharose 4B.
  • the void volume is collected and concentrated for use.
  • the ELISA is performed using microtiter plates coated with 50 ⁇ l/well containing 50 ⁇ g/ml of antigens whose concentration is estimated by using an extinction coefficient of 14 for a 1 % solution at 280 nm .
  • This assay is performed as previously described (16). Briefly, 1000 or 100 TCID 50 of HIV in100 ⁇ l is incubated with 100 ⁇ l of antibody or control protein for one hour at 37°C. The concentrations of monoclonal antibodies is adjusted to yield a final concentration of 0.5 mg/ml. After incubation, the treated HIV is added to 10° A3.01 cells and is incu- bated at 37°C for 2 hours in the presence of Polybrene at 10 ⁇ g/ml. The cells are then washed and resuspended in RPMI 1640 10% FCS at a density of 10 6 /ml.
  • RNA-free HIV is harvested from chronically infected A3.01 cell culture and titrated on uninfected A3- 01 cells. The titer is expressed as 50% tissue culture infective dose (TCID 51 ). Purification of Antl-CD4 Monoclonal Antibodies
  • the collection of selected anti-CD4 antibodies which will be used as an immunogen is purifed from mouse ascites using High Performance Liquid Chromatography on a Waters 600 system.
  • Monoclonal antibodies in either serum or ascites are diluted 1:10 with buffer A (25 mM MES, pH 5.4), filtered through a 1.45 ⁇ m filter and loaded on a Bakerbond ABx mixed-mode column (10 mm x 250 mm) at 2.5 ml/min. The column is then washed with buffer A until the A 280 is less than 0.010.
  • a linear gradient is developed from 100% buffer A to 75% buffer A, 25% buffer B (500 mM Ammonium Sulfate, 20 mM Sodium Acetate, pH 7.0) over 40 minutes.
  • the column is then taken to 100% buffer B over 10 minutes, washed with 10 column volumes water, and re-equilibriated with buffer A. Due to slight variations among different monoclonal antibodies, specific elution conditions are developed for each monoclonal antibody prior to scale- up for preparative purification. Typical yields are approximately 100 mg purified IgG per run. This system also will purify monoclonal antibodies under pyrogenfree conditions following GMP procedures.
  • the containers of ascites or serum are removed from the freezer and thawed in the refrigerator.
  • the thawed material is centrifuged at 10,000 rpm at 2-10°C for 30-60 minutes to remove additional fibrin clots that have formed.
  • the material can be ultracentrifuged, if necessary, at 30,000 rpm at 2-10°C for 30-90 minutes to aid in removing lipid.
  • the clarified material is aseptically withdrawn from the centrifuge tubes, leaving behind any additional fibrin clots, and refrigerated at 2-10°C.
  • An ammonium sulfate solution that is saturated at 4°C is prepared by mixing ammonium sulfate and sterile water for injection.
  • the pH of the ammonium sulfate is adjusted to 7.2 with ammonium hydroxide.
  • a calculated volume of the solution is added drop-wise to the ascites or serum to give a final solution that is 45% (v/v) ammonium sulfate solution, stirred and incubated overnight at 2-10°C.
  • the suspension of precipitated monoclonal antibody is then centrifuged at 9,000- 20,000 rpm for 30 minutes at 2-10°C. The supernatant is carefully poured off and discarded.
  • the precipitate is dissolved in TRIS Buffer and precipitated once again by the addition of saturated ammonium sulfate as described above. The precipitate is again dissolved in TRIS Buffer.
  • the monoclonal antibody is desalted chromatographically by passage over a column of Cellufine GH25, equilibrated with TRIS Buffer.
  • the monoclonal antibody elutes in the excluded volume of the column, free of ammonium sulfate. In some cases, the product is frozen and stored at this point in the processing.
  • the desalted monoclonal antibody is further purified by ion-exchange chromatography on DEAE-Fractogel. Selective elution of monoclonal-antibody enriched fractions is achieved by adjusting the relative % of sodium chloride in the running buffer. Further purification, if necessary, is achieved by a second ion-exchange chromatography step on a Mono-Q chromatography column. Again, selective elution of monoclonal-anti- body enriched fractions is achieved by adjusting the relative % of Buffers A & E. In some cases, the product may be frozen and stored either following ionexchange chromatography and/or Mono-Q chromatography. Re-precipitation by Ammonium Sulfate
  • the antibody is reprecipitated wiih a 50% (v/v) ammonium sulfate solution. This solution is added drop-wise to the antibody, stirred and incubated over night at 2-10°C. The suspension of precipitated monoclonal antibody is then centrifuged at 9,000-10,000 rpm for 30 minutes at 2-10°C. The supernatant is carefully poured off and discarded. The precipitate is dissolved in monoclonal antibody diluent.
  • the product is initially filtered after bufferexchange and before the adjustment of concentration.
  • the antibody solution is filtered into a non-pyrogenic glass bottle.
  • a sterile, non-pyrogenic, low protein binding, non-fiber releasing, 0-2 micron membrane filter is used to filter the solution.
  • Samples are taken at the bulk stage before bottling to determine immunoglobulin concentration, pyrogenicity , identify, purity and activity.
  • the product may be frozen in bulk after initial filtration. If frozen at this point, the product is thawed at temperatures between 2-10°C All steps are performed under aseptic conditions inside the clean room after the inital filtration step.
  • the concentration of monoclonal antibody is determined by analytical High Pressure Liquid Chromatography (HPLC). A calculated amount of monoclonal antibody diluent is added to adjust the concentration to the product specifications as required. The adjusted solution is then ready for final filtration.
  • HPLC High Pressure Liquid Chromatography
  • a sterile, pyrogen-free, low protein binding, non-fiber releasing, 0.2-micron membrane filter is used to finally filter the antibody solution into a sterile, non-pyrogenic glass bottle, under aseptic conditions.
  • the bulk container of investigational monoclonal antibody product is labeled "In-Process" and lists the product name, lot number, quantity, date produced, and storage conditions.
  • the bulk container is used for the aseptic filling of vials.

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  • Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Biophysics (AREA)
  • Biochemistry (AREA)
  • Genetics & Genomics (AREA)
  • Medicinal Chemistry (AREA)
  • Molecular Biology (AREA)
  • Proteomics, Peptides & Aminoacids (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Peptides Or Proteins (AREA)
  • Medicines Containing Antibodies Or Antigens For Use As Internal Diagnostic Agents (AREA)
  • Preparation Of Compounds By Using Micro-Organisms (AREA)

Abstract

Composés immunogènes comprenant une pluralité d'anticorps monoclonaux capables: (1) de bloquer la liaison d'un virus à son récepteur, et (2) de provoquer la formation d'un anticorps anti-idiotypique capable de se lier avec le virus. L'invention porte en outre sur des techniques pour produire ces composés.
PCT/US1988/003886 1988-11-01 1988-11-01 Methode pour diriger une reponse immunitaire vers un site de liaison viral WO1990004978A1 (fr)

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Application Number Priority Date Filing Date Title
PCT/US1988/003886 WO1990004978A1 (fr) 1988-11-01 1988-11-01 Methode pour diriger une reponse immunitaire vers un site de liaison viral

Applications Claiming Priority (1)

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PCT/US1988/003886 WO1990004978A1 (fr) 1988-11-01 1988-11-01 Methode pour diriger une reponse immunitaire vers un site de liaison viral

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WO1990004978A1 true WO1990004978A1 (fr) 1990-05-17

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992009305A1 (fr) * 1990-11-27 1992-06-11 Biogen, Inc. Anticorps anti-cd4 bloquant les syncytia provoques par le vih

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
J.W. KIMBALL, INTRODUCTION TO IMMUNOLOGY, 2nd Edition, published 1986, by Macmillan Publishing Company (New York), see pages 451-453. *
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES USA, Volume 84, issued June 1987, T.C. CHANH et al.: "Monoclonal anti-idiotypic antibody mimics the CD4 receptor and binds Human Immunodeficiency Virus", see pages 3891-3895, especially p. 3895. *
VACCINE, Volume 6, issued June 1988, A.G. DALGLEISH et al.: "Anti-idiotypic antibodies as immunogens: idiotype-based vaccines", see pages 215-220. *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992009305A1 (fr) * 1990-11-27 1992-06-11 Biogen, Inc. Anticorps anti-cd4 bloquant les syncytia provoques par le vih

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