ANTI-V3 ANTIBODY REACTIVITY CORRELATES WITH CLINICAL STAGE OF HIV-1 INFECTION AND WITH SERUM NEUTRALIZING ACTIVITY

During HIV-1 infection, the current tenet is that only anti-gag antibo dies decline, while those directed at env remain stable. Among the lat ter antibodies, those directed to the V3 domain of gp120 are assumed t o play a role in the immune surveillance against HIV-1. We investigate d the correlation between anti-V3 antibody levels and the clinical sta ge of infection and the ability to neutralize syncytium formation. Usi ng a V3-specific antigen-limited ELISA, we analysed the antibody level s of a panel of 93 HIV-1(+) sera to V3 peptides derived from different HIV-1 strains and from the North American/European consensus sequence V3(Cs). Sera preferentially recognized V3 peptides from the represent ative V3(MN) strain and V3(Cs). Antibody reactivity to V3(MN) or V3(Cs ) actually declined in relation with progression to AIDS, while antibo dies against whole recombinant gp160 or gp41 immunodominant epitope re mained stable. There was a strong correlation (P < 0.0001) between ant i-V3 (Cs)/V3(MN) antibody levels and serum titres that neutralized HIV -1(MN)-mediated syncytia. Serology based on V3-specific antigen-limite d ELISA indicates that anti-V3 antibody reactivity may decline during the course of HIV infection.