Human tgf β1

CD4⁺ T cells from spleens and lymph nodes of 6- to 8-week-old mice were purified by negative selection and magnetic separation (Miltenyi Biotec, Germany) followed by sorting of naive CD4⁺CD62L⁺CD44⁻ population using FACSAria II (BD, NJ). Cells were activated by plate-bound anti-CD3/CD28 (both 10 μg/ml; eBioscience, CA) in media for 3 days either under neutral conditions or IL-12 (10 ng/ml), anti-IL-4 (10 μg/ml, BD pharmingen) for Th1 differentiation, IL-4 (10 ng/ml), anti-IFN-γ (10 μg/ml, BD pharmingen) for Th2 differentiation, IL-6 (20 ng/ml) plus human TGF-β1 (2.5 ng/ml), anti-IFN-γ (10 μg/ml, BD pharmingen), and anti-IL-4 (10 μg/ml, BD pharmingen) for Th17 differentiation, TGF-β1 (20 ng/ml) and hIL-2 (100 U/ml) for iTreg differentiation unless specified.