ATP-competitive mTOR inhibition in vivo augments DC B7-H1 expression and their ability to induce Tregs. (A-D) DCs were differentiated in the presence of DMSO or WYE-125132 (WYE; 400 nM) from day 2 to day 8 and stimulated with LPS. Representative histograms (A) and quantification of CD86 (B) and B7-H1 (C) expression. MFI is indicated in the upper right corner of each histogram. (D) Ratio of B7-H1 to CD86 expression. Values were normalized to unstimulated DMSO DCs. (E-H) Mice were treated with WYE (50 mg/kg) and given LPS (100 μg/kg). Data are representative of n = 3 independent experiments. (E) Splenic CD11b⁺CD11c⁺ DCs were analyzed by flow cytometry for CD86 and B7-H1 expression 18 hours later with representative histograms shown. MFI values are shown in the upper right corner of each histogram. CD86 (F), B7-H1 (G), and the ratio of B7-H1 to CD86 (H) were determined across several experiments and normalized to the vehicle control. (I) Splenic DCs isolated in panel E were used to induce Tregs ex vivo from CD4⁺CD25^– BALB/c T cells. (J) T_reg induction was quantified across multiple experiments. Data are representative of n = 4 mice per treatment group. *P < .05 compared with DMSO.