Antibody and cellular immune responses in breakthrough infection subjects after HIV type 1 glycoprotein 120 vaccination

HIV-specific antibodies and CD8(+) T cell antiviral responses were evaluate d in three human immunodeficiency virus 1 (HIV-1) gp120 vaccine recipients who later became infected with HIV-1. Titers of neutralizing antibody to th e HIV-1(SF2) vaccine isolate were boosted, but titers of antibody to the au tologous infecting viruses were never high and required at least 6 months a fter HIV infection to develop. Similarly, a marginal noncytotoxic CD8+ T ce ll antiviral response was observed only in one of the three vaccinees 3 mon ths after HIV-1 infection. The infecting virus isolates had several amino a cid substitutions in the HIV-1 envelope V3 region but were similar to other regional HIV-1 clade B isolates, Viral loads were similar to those of othe r HIV-1-infected individuals who had not been vaccinated and transient CD4( +) T cell declines were observed in each person, suggesting that the vaccin e was not effective at controlling these prognostic markers early in infect ion.