Fig. 6

IDO induces a skewed IFN-γ⁺CD4⁺ T-cell response during JE. a, b The frequency and number of CD4⁺Foxp3⁺ Tregs in the spleen of IDO-ablated mice. The frequency (a) and absolute number (b) of CD4⁺Foxp3⁺ Treg cells in the spleen of wild-type and IDO KO mice were determined by flow cytometric analysis 5 dpi. The values in the representative dot plots show the average percentage of CD25⁺Foxp3⁺ cells in CD4⁺ T-cells; the bar charts denote the average number ± SD of CD4⁺Foxp3⁺ Tregs in the spleen derived from at least four mice per group. c, d The frequency and number of IFN-γ⁺CD4⁺ Th1 and IL-17⁺CD4⁺ Th17 cells in the spleen of IDO-ablated mice. The frequency and number of IFN-γ⁺CD4⁺ Th1 and IL-17⁺CD4⁺ Th17 cells were determined by intracellular cytokine staining of the splenocytes prepared from wild-type and IDO KO mice 5 dpi in response to PMA + ionomycin stimulation. The values in the representative dot plots show the average percentage of the indicated cell populations after gating on CD4⁺ T-cells; the bar charts denote the average number ± SD of IFN-γ⁺CD4⁺ Th1 and IL-17⁺CD4⁺ Th17 cells in the spleen derived from at least four mice per group. **p < 0.01 compared with levels in the indicated groups