Production of Human Monoclonal Antibodies Specific for Conformational and Linear Non-V3 Epitopes of gp120

Abstract

Three IgG1 human monoclonal antibodies (MAbs) directed against conformational epitopes of the gp120 envelope protein of HIV-1 were produced, as was a single human MAb to a linear epitope spanning amino acids 487-509 in the C-terminal portion of gp120. All three conformation-dependent MAbs reacted optimally with recombinant gp120 (rgp120) captured on plastic via its carbohydrate moieties with Concanavalin A. These MAbs were able to block the interaction between recombinant CD4 (rCD4) and rgp120; they were also able to achieve 50% neutralization of HTLV-IIIB and MN strains of HIV-1 in a concentration range of 0.5-12.8 micrograms/mL. The MAb to the linear determinant is the first reported human MAb specific for the immunodominant portion of gp120; this MAb was most reactive with rgp120 when it was coated directly on plastic. It could neither inhibit rCD4-rgp120 binding nor neutralize either HTLV-IIIB or MN. The binding affinities of the four human MAbs for rgp120 in solution, reflected by their dissociation constants (Kd), ranged from 0.5 x 10(-8) to 7.5 x 10(-8) M.

Vertical Transmission of HIV-1. Correlation with maternal viral load and plasma levels of CD4 binding site anti-gp120 antibodies.

“…The CD4 binding site on gpl20 does not represent a single epitope but instead appears to represent an "'epitope cluster" (8,(31)(32)(33). Both polyclonal antibodies purified from HIV-1-infected patient sera and human monoclonal antibodies derived from HIV-1-infected patient directed against this region neutralize many (but not all) laboratory and primary strains of HIV-1 (16)(17)(18)(36)(37)(38)(39).…”

Llama Antibody Fragments with Cross-Subtype Human Immunodeficiency Virus Type 1 (HIV-1)-Neutralizing Properties and High Affinity for HIV-1 gp120

“…MAb b12 (10) was kindly provided by D. Burton, Scripps Institute, La Jolla, CA. MAb GP68 (74) (29,37,40) and 447-52D (30,31) were obtained through the CFAR, NIBSC (original source, S. Zolla-Pazner). MAb 17b (79) was obtained from the NIH AIDS Research and Reference Reagent Program, Division of AIDS, NIAID, NIH (original source, J. E. Robinson).…”

“…Antibody b12 has been shown to bind to an epitope that overlaps a subset of the CD4bs (94). Human monoclonal antibodies 654-D and GP68 have been shown to compete with sCD4 for binding to recombinant gp120 but can only neutralize some T-cell-line-adapted isolates and not primary isolates (29,37,40,74).…”

Human Immunodeficiency Virus Type 1 Evades T-Helper Responses by Exploiting Antibodies That Suppress Antigen Processing

“…U08453) (11) and subtype B primary isolate TH14-12 (GenBank no. U08801) (11) were produced in Chinese hamster ovary cells and purified as described previously (4,29 (21,27), MAb 694/98-D recognizes an epitope in the V3 loop (14,16), and MAb 697-D recognizes the V2 loop (15). MAb 860-55D, which recognizes the parvovirus B19 VP2 antigen (12), was used as a negative control.…”