Fig. 3.

PD-1-expressing tumor-infiltrating T_reg and their activated phenotype in patients with non-small cell lung cancer (NSCLC). a CD25 and Foxp3 expression in CD4⁺ T cells (upper) and proportion of Foxp3⁺ cells among total CD4⁺ T cells (lower) in peripheral blood lymphocytes (PBLs), peritumoral infiltrating lymphocytes (pTILs), and tumor-infiltrating lymphocytes (TILs) derived from patients with NSCLC. b Representative plots of PD-1, TIM-3, TIGIT, CTLA-4, and Foxp3 expression in CD4⁺ T cells (left) and percentage of CD4⁺ T cells co-expressing PD-1, TIM-3, TIGIT, CTLA-4, and Foxp3 (right). c PD-1, TIM-3, TIGIT, and CTLA-4 expression in Foxp3⁺ T_reg, Foxp3⁻ T_conv and CD8⁺ T_conv of these patients. d Enhanced suppression of CD8⁺ T cells by PD-1-expressing tumor-infiltrating T_reg from NSCLC patients. T_reg were isolated from the peripheral blood and tumor tissue from NSCLC patients. Peripheral blood T_reg and tumor-infiltrating T_reg expressed low and high levels of PD-1, respectively. CellTrace Violet (CTV)-labeled CD8⁺ T cells were stimulated in vitro with CD3/CD28 Dynabeads for 96 h in the absence or presence of each T_reg population. CTV dilution in proliferating CD8⁺ T cells is indicated in each histogram. Histograms represent the percentages of proliferating cells. Lines in the bar graph represent the mean and mean ± SEM, respectively. ns, not significant; **P < 0.01, ***P < 0.001 (Mann-Whitney test)