HIV Gag-specific CD8⁺ T-cell responses in blood and rectal mucosa. (A) Total percentage of CD8⁺ T cells from peripheral blood (left panels) or rectal mucosa (right panels) able to respond in any way (CD107a, IFN-γ, IL-2, MIP-1β, or TNF-α) to Gag stimulation. Percentage of CD8⁺ T cells capable of producing IFN-γ (B), MIP-1β (C), TNF-α (D), and CD107 (E) in response to Gag stimulation. Horizontal bars represent the median for each group. *P < .05, **P < .01, ***P < .001.