TSLP enhances FoxP3 induction in FTOC. A: Induction of FoxP3 expression in FTOC with E17 fetal thymus. Total thymocytes were harvested at 2, 4 and 6 days after E17-FTOC and analyzed for relative expression of FoxP3 (FoxP3/18S) by real-time PCR. SD is derived from duplicate samples and shown as error bars. At least 3 independent experiments were performed. B: Enhancement of FoxP3 expression by exogenous TSLP in FTOC. FTOCs treated with TSLP (100 ng/ml) were harvested after 4 days and analyzed as above. Shown are representative data from at least three independent experiments. C: Endogenous TSLPR activity is required for induction of FoxP3 expression. FTOCs were treated with control IgG or anti-TSLPR antibody. FoxP3 expression after 4 days in culture was analyzed by real-time PCR as above. Error bars indicate standard errors from duplicate samples. * indicates p < 0.05. D: FACS analysis of FoxP3 expression in thymocytes from FTOC stimulated with exogenous TSLP. FTOC treated with TSLP was harvested at 4 days post FTOC as above. CD4+CD8- thymocytes were gated for analysis of CD4 vs. CD25 and CD25 vs. FoxP3 or isotype control. Shown are representative data from three independent experiments.