Direct and DC-mediated in vivo induction of Foxp3⁺ CD4⁺ Tr cells by AhR activation. Mice treated with oral VAG539 (n = 3) and VAG-DC– or naive-DC–injected mice were analyzed 100 days after transplantation for the expression of Foxp3 and CD25 by splenic CD4⁺ T cells compared with naive Balb/c mice. (A) The percentage of gated CD4⁺ T cells expressing Foxp3 following oral VAG539 treatment or VAG-DC injection (2-tailed t test: *P < .05). Error bars represent standard error between different mice (n = 3). (B) Top numbers represent percentage of gated CD4⁺ T cells and bottom numbers represent MFI (Foxp3-PE channel). (C) VAF347 improves survival of CD4⁺CD25⁺FOXP3⁺ T cells in vitro. Splenic CD4⁺ T cells were cultured for 5 days in the presence or absence of VAF347 at 20 nM or 100 nM. Gated CD4⁺ T cells were analyzed for the expression of CD25 and FOXP3. Number represents the percentage of CD25⁺FOXP3⁺ T cells. (D) Transfer of splenic CD4⁺CD25⁺ T cells (5 × 10⁵; purity > 90%) from VAG-DC–injected mice and from naive mice into mice that recently underwent transplantation 1 day prior to allotransplantation (2-tailed t test: *P < .05).