Hes1 is critical for the development of IL-17–producing γδ T cells. (A-B) Hes1 is dispensable for the development of γδ T cells. (A) Absolute numbers of γδ T cells in fetal thymi (E16, left; E18, right) of Hes1^+/− (+/−) and Hes1^−/− (−/−) mice were calculated after analyzing by flow cytometry. Data shown are the means ± SD of 4 fetuses for each group. (B) Representative dot plots for the expression of Vγ4 and Vγ5 in fetal thymi (E16) are shown after gating on γδ TCR⁺ cells. The numbers under each panel indicate the percentages of positive cells in the respective quadrants. (C-D) Hes1 is required for the development of IL-17–producing γδ T cells. IL-17 production by γδ T cells from E16 (top panels) and E18 (bottom panels) of Hes1^+/− (+/−) and Hes1^−/− (−/−) mice were analyzed after stimulation with PMA and ionomycin. (C) Representative dot plots are shown after gating on CD3⁺ cells. The number in the top right quadrant indicates the percentage of IL-17⁺ cells in γδ TCR⁺ cells. (D) Absolute numbers of IL-17⁺ γδ T cells are shown. Data shown are the means ± SD of 4 mice. *P < .05. Data are representative of 3 independent experiments.