Association between HIV Type 1-Specific T Cell Responses and CD4 + T Cell Counts or CD4 + :CD8 + T Cell Ratios in HIV Type 1 Subtype B Infection in China

CD4⁺ T cell counts and CD4⁺:CD8⁺ T cell ratios represent key determinants of HIV disease progression and infectivity. However, the relationship between the HIV-1-specific cytotoxic T lymphocyte (CTL) response and these determinants has not been elucidated for all HIV-1B and HIV-1C proteins. In the present study, virusspecific T cell responses to HIV-1B and HIV-1C proteins were analyzed with interferon gamma (IFN-γ) enzyme- linked immunospot (ELISpot) assays using synthetic overlapping peptides corresponding to naturally occurring HIV-1B and HIV-1C consensus sequences. For Gag/Gag p24/Gag p17, a correlation between T cell responses and CD4⁺ T cell count in HIV-1 clade B and clade C was seen: elevated T cell response resulted in higher CD4⁺ T cell production. A statistically significant correlation between the Pol-specific T cell response and CD4⁺ T cell counts was also found in HIV-1 subtype C. For all HIV-1B and HIV-1C proteins, a correlation between the HIV-1-specific T cell response and CD4⁺:CD8⁺ T cell ratios was found for Tat and Pol proteins. CD4⁺ T cell counts in patients with Tat and/or Rev T cell response were higher than in patients without Tat and/or Rev T cell response. We suggest that this correlation within HIV-1B and HIV-1C Gag p24/Gag p17 responses makes the Gag p24/Gag p17 region a potential vaccine candidate and that HIV-1-specific CTL epitopes toward Pol are important in controlling HIV-1 infection; we emphasize that future vaccination strategies should include these early antigens, Tat and Rev.