Functional property of IL-7R–expressing effector CD8⁺ T cells. (A) Perforin expression of CXCR1/IL-7Rα subsets in the CD27⁻CD28⁻ effector CD8⁺ T-cell subset is shown as 1 representative result from 3 healthy individuals. (B) FACS-sorted CXCR1⁺ and CXCR1⁻ effector subsets were treated with IL-7 (10 ng/mL) for 15 minutes, and then stained for pSTAT5 expression. Representative pSTAT5 staining with the percentage of pSTAT5⁺ cells in each subset and the percentage of pSTST5⁺ cells in each effector subset from 4 individuals are shown. (C) FACS-sorted CXCR1⁺ and CXCR1⁻ effector subsets were cultured with or without IL-7 (5 ng/mL) for 48 hours, and then dead cells were detected by 7-amino-actinomycin D (7-AAD) staining. Representative results of 7-AAD staining with percentages of 7-AAD⁺ cells in each subset (without IL-7 in gray and with IL-7 in black) and the percentage of 7-AAD⁺ dead cells in each effector subset from 4 individuals shown. (D) FACS-sorted CXCR1/IL-7Rα subsets (far left plots) from healthy subject number U-14 were stimulated with PMA and ionomycin for 6 hours to assess the percentage of cytokine-producing cells. The flow plots are presented as a representative result from 3 healthy individuals showing similar results. (E) The CD8⁺, tetramer-positive cells from a HCMV-seropositive healthy subject (U-14) were analyzed for IL-7R expression. The frequency of tetramer-positive cells in each CXCR1/IL-7R effector CD8⁺ T-cell subset is shown. (F) CXCR1/IL-7Rα subsets were sorted to assess the cytolytic activity toward C1R-A*0201 cells prepulsed or not with the HCMV-1 pp65^495-503 peptide.