查看文章

Naturally acquired cellular immunity in individuals who have been exposed to HIV-1 but have remained uninfected may hold clues for the design of an effective HIV vaccine. To determine the presence and nature of such an HIV-1-specific immune response, we evaluated the quantity and fine specificity of HIV-1-reactive IFN-γ-secreting T cells in a group of highly exposed seronegative men having sex with men. All 46 ES reported frequent unprotected anal sex with known HIV-1-infected partners at enrollment, and high risk activities continued in at least one-half of the volunteers for up to> 6 years of observation. Despite the high frequency of unprotected anal intercourse and potential HIV-1 exposure, the vast majority of individuals demonstrated no or very low numbers of HIV-1-specific, IFN-γ-secreting T cells. Even when HIV-1 epitopes were presented by peptide-pulsed autologous dendritic cells in 15 of the highest …