IL-15 increases anti-CD3–induced and antigen-specific activation of HIV-specific CD8⁺ T cells.

(A) Representative flow cytometry from one HIV-infected individual showing CD69 expression on Gag-specific CD8⁺ T cells after stimulation of PBMCs with anti-CD3 ± IL-15 for 14 hours. FACS plots show CD8⁺ T cells that were gated for lymphocytes by FSC and SSC and then for CD8⁺ T cells by CD8 staining. (B) Pooled data showing CD69 expression on HIV-specific CD8⁺ T cells from HIV-infected individuals after stimulation of PBMCs with anti-CD3 ± IL-15 for 14 hours (n = 8). Bars depict means ± standard errors. (C) Representative flow cytometry from one HIV-infected individual showing CD69 expression on Gag-specific CD8⁺ T cells after stimulation of PBMCs with Gag-specific tetramer ± IL-15 for 3 hours. FACS plots show CD8⁺ T cells first gated for lymphocytes by FSC and SSC and then by CD8 staining. (D) Pooled data showing CD69 expression on HIV-specific CD8⁺ T cells from HIV-infected individuals after stimulation of PBMCs with HIV-specific tetramer ± IL-15 for 3 hours (n = 5). Bars depict means ± standard errors. The P values were calculated by using nonparametric Wilcoxon signed rank test for paired samples for the graph in Panel B and Student t test for paired sample for the graph in Panel D.