CD4⁺CD161⁺drug-effluxing T cells maintain c-kit expression after stimulation. CD4⁺CD161⁺ T cells were sort-purified according to rhodamine effluxing capacity (Rho^lo and Rho^hi) and were stained for c-kit expression after stimulation with anti-CD3/CD28 beads. (A) Representative FACS plots depict c-kit expression on CD4⁺CD161⁺Rho^lo T cells in response to stimulation. (B) Cumulative data from 5 independent experiments show the c-kit expression on CD4⁺CD161⁺Rho^lo, CD4⁺CD161⁺Rho^hi, and CD4⁺CD161⁻. Statistics were calculated using Student t test. *P < .05; **P < .01; ***P < .001; ****P < .0001; ns = not significant. (C) CD4⁺CD161⁺ T cells were stained for ABCB1, followed by intracellular staining for Ki67. Representative dot plots show the expression of Ki67 on ABCB1⁺ vs ABCB1⁻ CD161⁺CD4⁺ T cells. Cumulative data demonstrate the higher expression of Ki67 on ABCB1⁻ noneffluxing CD161⁺CD4⁺ T cells. Mean ± SE of 3 separate experiments were shown.