Impact of γ_c deletion on CD4⁺ regulatory T cells and iNKT cells. (A) TCR-β^hi CD4SP thymocytes were analyzed for Foxp3⁺ cells from Cre⁻ control mice (black bar) and for γ_c-deleted Foxp3⁺ cells from γ_c-cKO (red bars) and γ_c-cKO-Bcl2 transgenic (purple bar) mice. Total Foxp3⁺ CD4SP thymocytes from γ_c-cKO mice are shown (plain red) or after specifically gating on γ_c-deleted Foxp3⁺ CD4SP thymocytes (red with black). Frequencies of Foxp3⁺ cells among CD4SP cells are shown. Means of at least three mice are shown, and error bars represent SEM. **, P < 0.01; ****, P < 0.0001. (B) γ_c expression on Foxp3⁻ (non–T reg cells) and Foxp3⁺ CD4SP thymocytes. CD4SP thymocytes were gated on Foxp3⁻ and Foxp3⁺ subsets and analyzed for expression of γ_c from γ_c-cKO (red) compared with Cre⁻ control (black) mice. Gray histograms represent negative staining controls. Data are representative of at least three individual mice. (C) CD4SP thymocytes were analyzed for TCR-β⁺ CD1d-tetramer⁺ iNKT cells from Cre⁻ control (black bar), γ_c-cKO (red bar), and γ_c-cKO-Bcl2 transgenic (purple bar) mice. Frequencies of iNKT cells among CD4SP cells are shown. Means of at least three mice are shown, and error bars indicate SEM. *, P < 0.05. (D, Top) The frequency of iNKT cells in various tissues. Total thymocytes, splenocytes, or lymphocytes prepared from the liver of γ_c-cKO (red) or Cre⁻ control (black) mice were analyzed for expression of TCR-β and binding of CD1d-tetramer. Data are representative of at least three individual mice. (D, Bottom) Quantitation of pooled data from Cre⁻ control (black) or γ_c-cKO (red) mice. Means of at least three mice are shown, and error bars indicate SEM. *, P < 0.05; **, P < 0.01.