Fig. 3.

IFNγ/IL-4 inhibits Foxp3 induction via the canonical signaling pathways required for Th1/Th2 lineage differentiation. Naïve CD4⁺ T cells from WT mice, Stat1^−/−, and T-bet^−/− were stimulated by soluble anti-CD3/spleen APC (A) or plate-bound anti-CD3/soluble anti-CD28 (B) in the presence of 1 ng/ml TGF-β1. IFNγ (100 ng/ml) was added to the cultures as indicated. (C) Naïve T cells from WT and Stat6^−/− mice were stimulated by plate-bound anti-CD3/soluble anti-CD28 in the presence of 1 ng/ml TGF-β1. IL-4 (10 ng/ml) was added to the cultures as indicated. Representative FACS plots of Foxp3 staining are shown with the percentage numbers averaged from two independent experiments.