Expansion of Tregs by BMDCs <i>in vitro</i>.

<p><b>A, B, </b><i>In vitro</i> antigen-specific expansion of iTregs via the indirect pathway. Naïve CD4⁺ T cells from CBA mice were cultured with BMDCs (CBA) in the presence of the K^b peptide for 7 days at the indicated conditions. The Treg fraction was determined as CD3⁺CD4⁺ CD25⁺Foxp3⁺ (***<i>P</i><0.001, Bonferroni test) <b>C, D,</b> The-time course of Treg fraction (C) and number (D) in the <i>in vitro</i> culture with BMDCs in the presence of 10 µg/ml K^b peptide, 10 ng/ml IL-2, 2 ng/ml TGF-β, 5 µg/ml anti- IFN-γ and anti-IL-4 antibodies, and 20 nM ATRA. <b>E,</b> The cell surface marker and purity of the Tregs before and after cell sorting, on day 8 after culture via the indirect and direct pathway. Tregs induced via the direct pathway were cultured with C57BL/6 BMDCs and 10 ng/ml IL-2, 2 ng/ml TGF-β, 10 µg/ml anti- IFN-γ and 5 µg/ml anti-IL-4 antibodies, and 20 nM ATRA. The cells were stained with the indicated antibodies and analyzed with FACS.