Percentages of IFN-γ–producing T cells early and late in HIV infection determined after in vitro stimulation with peptide, peptide and costimulation, or PMA and ionomycin.

Data from progressors (n = 11, (●) include early samples versus samples drawn during AIDS diagnosis. Data from asymptomatics (n = 5, ○) are early samples versus latest sample available before HAART. (A) IFN-γ⁺ fraction of tetramer⁺ HIV-specific T cells early versus late in infection, measured by stimulation of PBMCs with 1 μg peptide/mL. Thirteen of all 16 individuals showed a decrease in the fraction of antigen-induced IFN-γ production during disease progression (n = 16; P = .028, Wilcoxon). Progressors and asymptomatics had different dynamics of the IFN-γ⁺ fraction as shown by different Pvalues. (B) IFN-γ⁺ fraction of tetramer⁺HIV-specific T cells after stimulation with 10 μg peptide in the presence of CD28 and CD49d costimulation. (C) PBMCs of HIV-infected individuals were incubated with PMA and ionomycin to investigate the antigen-independent IFN-γ production during the course of HIV infection. Included are percentages IFN-γ–producing CD8⁺T cells (left panel) and tetramer⁺ T cells (right panel).