Fig. 2.

Tregs induce amino acid-consuming enzymes in DCs as do CTLA4, IL-10, and TGF-β. (A–C) Immature bmDCs from female CBA/Ca mice were cultured either alone (white bars) or together (1:1 ratio) with male-specific TCR transgenic Tregs (A), similar, but conventionally activated, T cells (Tconv) (B), or Tr1D1 (a Tr1 cell clone) (C), both with (black bars) or without (striped bars) the cognate DBY antigen peptide, for 24 h at 37 °C. Samples were then analyzed for the expression of gene transcripts by low-density TaqMan RT-PCR array. * indicates gene transcripts significantly overexpressed only in the presence of T cells plus cognate peptide. (D) Splenic DCs (10⁶/mL) from CBA/Ca (slashed and black bars) or CBA.IDO^−/− (striped and gray bars) mice, as indicated, were cultured either with (slashed and striped bars) or without (black and gray bars) CTLA4-Ig (100 μg/mL) for 48 h, before analysis for the expression of gene transcripts by low-density TaqMan RT-PCR array. * indicates gene transcripts significantly overexpressed, in the presence of CTLA4-Ig, in either wild-type or IDO^−/− T cells. (E) Gene transcripts were measured in immature DCs (white bars) or LPS-treated DCs that had been exposed to TGF-β (slashed bars), IL-10 (striped bars), or no additional cytokines (black bars) during their generation from bone marrow cultures, and analysis as above. * indicates gene transcripts up-regulated by TGF-β or IL-10 over and above that seen by LPS exposure alone. Data are shown as the mean ± SD log₁₀(RQ) values of at least 3 independent biological replicates.