Combined effects of TGF-β1/Fc and rapamycin on the differentiation of Foxp3+ Treg and Th17 cells from naive CD4 T cells. Flow-sorted naïve CD4+GFP- T cells from B6.Foxp3GFP knock-in mice were stimulated with anti-CD3 and anti-CD28 mAbs for 72 h (A), or cultured with LPS-matured allogeneic DC for 7 days (B), alone or in the presence of TGF-β1/Fc (5 μg/ml) and/or rapamycin (5 ng/ml). GFP+(Foxp3+) cells in the responder CD4+ T cell population were analyzed by flow cytometry. (C) IL-6 and IL-17 levels in mature DC-T cell culture supernatants were determined by ELISA. (D) Flow-sorted CD4+CD25- T cells from B6.CD45.1 were transferred to B6D2F1 mice by i.v. injection. The hosts were treated on day 0, 1, 2 with TGF-β1/Fc (0.1 mg) or rapamycin (0.6 mg/kg), alone or together. Data depict flow cytometric analysis of Foxp3+ cells converted from CD45.1+CD4+ T cells harvested from spleens of B6D2F1 mice on day 4. Data are representative of four independent experiments. *p < 0.01 versus untreated control.