HIV-specific T cell immunity across the entire HIV genome in Chinese men who have sex with men

Abstract

Man who has sex with man (MSM) is one of the high risk groups for spreading HIV/AIDS. It was reported that the most prevalent human immunodeficiency virus type 1 (HIV-1) strain among MSM is subtype B; however, T cell immunity remains unknown across the HIV-1 B genome in this population. Using Elispot assay with synthetic peptides spanning the sequence of HIV-1 consensus B, HIV-1-specific cytotoxic T-cell lymphocyte responses were quantified among 3 treated and 19 untreated HIV-1 infected MSM from Beijing, China. Cross-sectional association between viral loads and cellular immune responses were analyzed. Peptide pools corresponding to each HIV-1 protein were used for Env, Gag, Pol, Nef, Tat/Rev, Vpr/Vpu and Vif. The results showed that the magnitude of T cell responses in the 3 treated HIV(+) MSM group [median, 770 spot forming cells (SFCs) per 10(6) peripheral blood mononuclear cells (PBMCs)] might be significantly lower than that in the 19 untreated HIV(+) MSM group (median, 6175 SFCs per 10(6) PBMCs). Nef, Gag and Pol are the most frequently targeted HIV-1 antigens; and 16 subjects (73%) were identified with vigorous T cell immunity against each of these three proteins. The overall magnitude of T cell immunity closely related to its breadth (r = 0.72, P < 0.05) and was inversely but weakly associated with viral loads (r = -0.15). Further analysis showed that both Gag (r = -0.24) and Pol specific T cells (r = -0.12) contributed to this inverse association whereas Nef specific T cells showed no association with viral loads. The magnitude of HIV-1 specific T cells is inversely but weakly associated with viral loads among MSM; HIV-specific T cell responses against conservative sequences (Gag and Pol) are the main contributors to this association among Chinese HIV(+) MSM. These findings have important implications for vaccine design.