IL-15 decreases CD95/Fas-induced apoptosis of effector memory HIV-specific CD8⁺ T cells.

(A) Representative flow cytometry showing Annexin V staining of effector memory HIV-specific CD8⁺ T cells after stimulation of PBMCs with anti-CD95/Fas antibody ± IL-15 for 14 hours. Histograms show effector memory subpopulations of HIV-specific CD8⁺ T cells. Cells were gated for lymphocytes by FSC and SSC, for tetramer-specific CD8⁺ T cells by tetramer staining, and then based on CD45RA and CD62L expression. (B) Pooled data showing Annexin V binding of HIV-specific CD8⁺ T cells after stimulation of PBMCs with anti-CD95/Fas antibody ± IL-15 for 14 hours (n = 10). (C) Percentage of treatment-specific apoptosis shown for CD45RA⁻CD62L⁻ and CD45RA⁺CD62L⁻ effector memory HIV-specific CD8⁺ T cells (n = 10). For treatment-specific apoptosis calculation see “Patients, materials, and methods.” Bars depict means ± standard errors. The P values were calculated by using Student t test for paired samples.