Fig. 3.

IDO2 ablation attenuates IDO1-dependent Treg generation. Treg suppression assays were performed essentially as described before (25). Briefly, MACS-enriched CD4⁺CD25⁺ cells obtained from WT or Ido2 ^−/− mice treated i.v. with 100 µg CpG 1826 oligonucleotide were mixed with MACS-enriched CD4⁺ T cells from A1 TCR-transgenic mice, MACS-enriched CD11c⁺ APC from female CBA spleen and H-Y-E^k cognate peptide. IDO1 dependence in this assay was discriminated as established previously by adding a mixture of antibodies against PD-1, PD-L1 and PD-L2 (25). The experiment was repeated once with data obtained from samples processed in triplicate (mean ± standard error).