Anti-V3 and anti-IgG antibodies of healthy individuals share complementarity structures.
It was recently shown that antibodies reactive with a peptide from the tip of the HIV-1NY5 gp120 V3 loop (V3 peptide) are present not only in sera of HIV-positive patients but also in sera of healthy HIV-negative individuals. In the present study, we show that V3 peptide reactive antibodies are predominantly IgM in sera of HIV negative individuals and that a fraction of the IgG anti-V3 antibodies exhibit features of autoantibodies. These antibodies were purified by chromatography on IgG-sepharose columns from sera as well as from purified IgG anti-V3 antibodies. A higher IgG anti-V3 reactivity was detected in autoantibody preparations from HIV-positive sera as compared with the reactivity of sera and purified antibodies from HIV-negative individuals. This was confirmed by solid phase binding of IgG anti-V3 antibodies both to V3 and to human IgG F(ab')2 antigens. The autoantibodies did not bind to peptides that share sequence similarity with V3 peptide indicating a high epitope specificity. The detection of antibodies against HIV epitopes in HIV-negative individuals may suggest that anti-V3 antibodies after HIV infection represent at least in part a secondary immune response.
Metlas
R
R
R&D Division, Diapharm, Belgrade, Yugoslavia, and Diapharm Ltd., St. Peterport, Guernsey, Channel Islands, UK. os2@ets.it
Trajkovic
D
D
Srdic
T
T
Veljkovic
V
V
Colombatti
A
A
D000888:Antibodies, Anti-Idiotypic / Q000097:blood / Q000737:chemistry*; D000915:Antibody Affinity; D001323:Autoantibodies / Q000097:blood / Q000737:chemistry; D003429:Cross Reactions; D015483:HIV Antibodies / Q000097:blood / Q000737:chemistry*; D015699:HIV Envelope Protein gp120 / Q000276:immunology*; D018023:HIV Seronegativity / Q000276:immunology; D006679:HIV Seropositivity / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000737:chemistry / Q000276:immunology*; D007075:Immunoglobulin M / Q000097:blood / Q000737:chemistry; D007135:Immunoglobulin Variable Region / Q000097:blood / Q000737:chemistry*; D010446:Peptide Fragments / Q000276:immunology*
D000888:Antibodies, Anti-Idiotypic; D001323:Autoantibodies; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120; C059762:HIV envelope protein gp120 (305-321); D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007135:Immunoglobulin Variable Region; D010446:Peptide Fragments