IL-15 mediates the expansion of antigen-specific CD8⁺ but not CD4⁺ T cells. (A) Percent Ki-67⁺ SIV-specific (Gag and Nef averaged) and CMV-specific CD4⁺ T-cells and (B) CD8⁺ T cells before and after therapy introduction. N/A indicates data not available because of low number of responding cells. Data are expressed as in Figure 2B. #P < .05 vs ART; Wilcoxon rank-sum test. (C) Percent of Gag-, Env-, or CMV-specific CD4⁺ (top) and CD8⁺ (bottom) T cells producing cytokines (IL-2 or TNF-α or IFN-γ) in the different treatment groups in the peripheral blood at d−7 or at d46 after therapy initiation. Data are expressed as in Figure 1B. (D) As in panel C but in the ILN and the BAL at baseline (“pre”) and at d28. Data from the jejunum are not depicted because very low responses were detected.