PLCγ1 deficiency impairs T reg cell development and function. (A) PLCγ1-deficient T cells display activated phenotype. Data are representative of four pairs of mice. (B) Percentages of FoxP3⁺ T reg cells in total and CD4-gated lymphocytes in the thymus, spleen, and lymph node cells. Data represent five pairs of mice. (C) CD4⁺FoxP3⁺ cell numbers were reduced in thymus and spleen of Cre/PLCγ1^fl/− mice. Data represent five pairs of mice. (D) PLCγ1 deficiency impairs the inhibitory functions of T reg cells. Error bars represent the standard deviation of triplicate measurements of each data point. *: P < 0.05, **: P < 0.01. Data are representative of two independent experiments. (E) WT T reg cell reconstitution restores normal weight gain in Cre/PLCγ1^fl/− mice. Each point represents the mean weight of 7 to 14 female Cre/PLCγ1^+/− mice or 6 female Cre/PLCγ1^fl/− mice that received WT T reg cells. (F) WT T reg cell reconstitution restores high CD62L expression on PLCγ1-deficient T cells. Data represent three independent experiments.