IFN-γ blockade prevents impaired differentiation of Ezh2-null naïve CD4+ T cells. (A) Schema of mixed-cell culture conditions. (B) iTreg differentiation in mixed-cell cultures as illustrated in (A) in the presence or absence of IFN-γ–blocking antibody. (C) Expression of T-bet at day 6 in differentiated cells. (D) Cytokine production in Th2 and Th17 cells in the presence or absence of IFN-γ blockade. (E) IFN-γ production by naïve CD4+ T cells activated by phorbol myristate acetate (PMA)+ionomycin for 5 hours, and expression of IFN-γ receptor (Ifngr2), IL-12 receptor (Il12rb2), and T-bet genes in naïve CD4+ T cells. (F) Activation of STAT1 and STAT4 in 4-day differentiated T cells in the presence (+) of absence (–) of IFN-γ blockade when restimulated by PMA+ionomycin for 5 hours. Results shown are mean ± SEM of duplicates, representative of 3 independent experiments.