Effector phenotype of donor T cells in target organs is not changed by IDO. B6 or IDO^−/− mice were lethally irradiated and infused with Balb/c TCD BM and 3 × 10⁶ CD4⁺ and CD8⁺ T cells. At 21 days after transplantation, T cells were isolated from colons and livers, stimulated with plate-bound anti-CD3 for 4 hours, and stained for IFN-γ, IL-4, granzyme B, and IL-10; n = 4 mice/group. No significant differences were observed.