Stimulation of antiviral antibody response in SHIV-IIIB-infected macaques

Three macaques infected with SHIV-IIIB and expressing the shared 1F7-idioty pic marker on antibodies against HIV-1 gp120, were injected intravenously w ith 1F7 monoclonal antibodies (MoAb). As controls, a SHIV-IIIB-infected mac aque was injected with a HIV-unrelated mouse monoclonal isotype antibody (T EPC-183) and two healthy, noninfected macaques were injected with MoAb 1F7. 1F7-id-expressing antibodies against gp120-IIIB decreased in two of the th ree MoAb 1F7-treated macaques and then rebounded. Importantly, antibodies b inding to envelope proteins of heterologous HIV-1 strains MN, CM, and SF2, which were low or not detectable before the MoAb 1F7 treatment, increased r apidly following MoAb inoculations in all three 1F7 MoAb treated macaques, but not in the macaque injected with control MoAb TEPC-183. Newly arising a ntibodies reacting with heterologous virus, i.e. HIV-1 gp120-MN, SF2, and C M did not express 1F7-id. Surprisingly, significant increases of antibodies were also observed in the 1F7-inoculated macaques' antibodies directed to non-HIV antigens (DNP, peptides and BSA). The noninfected control animals d id not produce antibodies to these antigens despite MoAb 1F7 treatment. The se data show that the MoAb 1F7 injections of chronically SHIV-IIIB-infected macaques resulted in idiotype-specific clonal suppression with broadening the antibody response to HIV envelope proteins.