Enhanced induction of Tregs by Torin1-exposed DCs is B7-H1 and IL-1β dependent. (A) WT or B7-H1^−/− DCs propagated in the indicated mTOR inhibitor were washed extensively and used as stimulators of CD4⁺CD25^– normal BALB/c T cells in a 5-day CFSE-dilution MLR. (B) Percent of proliferating T cells (CFSE^lo) was calculated across multiple experiments. (C) Representative contour plots depicting the percentage of induced Tregs (CD25^hiFoxp3⁺) in the MLR from panel A are shown. (D) The data from panel C were calculated across multiple experiments. (E) Representative contour plot of CFSE dilution of Foxp3⁺ and Foxp3^– T cells. (F) Quantification of multiple experiments from panel E. *, #, ^ P < .05 compared with WT DMSO, WT RAPA, and the corresponding WT condition, respectively. IL-1β was neutralized in MLR, and T_reg induction determined as in panel C (G) and quantified across experiments (H). *, ^ P < .05 compared with corresponding isotype control and WT conditions, respectively, unless otherwise indicated. All data are representative of n ≥ 3 independent experiments. In some experiments, transforming growth factor β (TGFβ) (10 ng/mL) was added at the start of culture as a positive control, and T cells without DC stimulators were included as a negative control.