Phenotypic and functional characteristics of HIV-specific CD8 T cells and gag sequence variability after autologous dendritic cells based therapeutic vaccine

A decrease in HIV-1 specific CD8 T-cell responses associated with a partial control of viral replication occurred in 12 HIV-1-infected patients during autologous dendritic cells vaccination. HIV CD8 T cells were detected in 6/10 patients during immunizations, increasing after HAART discontinuation in 3 of them. Tet+ CD8 cells mainly had an effector phenotype (CD45RA−/+ CCR7− and CD28− and Perf+/−) and maintained IFN-γ release throughout follow-up. By contrast, patients with CD45RA−/+ CCR7+ Perf+ HIV-specific cells showed a decrease in peptide-specific IFN-γ production during vaccinations while levels were recovered when off HAART. No major mutations in either Gag p24 and p17 immunodominant epitopes were observed that might have explained the impaired CD8+ T-cell responses. Taken together, heterogeneity in the maturation status of HIV-specific CD8 T cells may be partially involved in the drop of peptide-specific IFN-γ production during immunizations.