Short Communication 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 evaluated in three human immunodeficiency virus 1 (HIV-1) gp120 vaccine recipients who later became infected with HIV-1. Titers of neutralizing antibody to the HIV-1_{SF 2} vaccine isolate were boosted, but titers of antibody to the autologous infecting viruses were never high and required at least 6 months after HIV infection to develop. Similarly, a marginal noncytotoxic CD8 + T cell antiviral response was observed only in one of the three vaccinees 3 months after HIV-1 infection. The infecting virus isolates had several amino acid 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 other HIV-1-infected individuals who had not been vaccinated and transient CD4 + T cell declines were observed in each person, suggesting that the vaccine was not effective at controlling these prognostic markers early in infection.