Different expression of 3 cytokines in CXCR1⁺ and CXCR1⁻ effector subsets of CD8⁺ T cells. (A) FACS-sorted CXCR1⁺ and CXCR1⁻ CD27⁻CD28⁻ CD8⁺ T cells from healthy subject number U-14 were stimulated for 6 hours with PMA and ionomycin to determine the percentage of each kind of cytokine-producing cell. (B) The mean percentage and SD of each type of PMA and ionomycin-induced cytokine-producing cell in each CD8⁺ T-cell subset from 7 individuals are shown.