Post treatment effects of IL-15 therapy. (A) Fold change in the absolute count of total CD4⁺ T cells in the peripheral blood at d59 (d13 posttherapy interruption) in the ART and ART+IL-15 groups. Each point represents an animal. The median ± SEM is depicted. (B) Representative example of the expression of phosphatidylserine on the cell surface by d59 T_EM CD4⁺ T cells after overnight culture. (C) Summary of the data as in panel B but also from T_N and T_CM CD4⁺ T cells. #P < .05 vs ART; Wilcoxon rank-sum test. (D) Fold change in the absolute count of CD4⁺ T cells with different differentiation phenotypes in the peripheral blood at d59 (d13 posttherapy interruption) in the ART and ART+IL-15 groups. Data are depicted as in Figure 2A. #P < .05 vs ART; Wilcoxon rank-sum test. (E) Bar graph and (F) pie charts representing the quality of the SIV-specific (Gag and Env averaged) CD4⁺ T-cell response at days 46, 59, and 70 in the ART and ART+IL-15 groups. Colors in the pie charts corresponding to different cytokine combinations are indicated at the bottom of panel C. #P < .05 vs d46. (E) Percentage of SIV-specific (Gag and Env averaged) CD4⁺ T cells with T_CM, T_TM, or T_EM phenotype of total memory cells before treatment interruption (d46) and at days 59 and 70. Data were expressed as in Figure 1B. # = P < .05 vs d46.