IL-12– and IL-23–induced IFN-γ production is impaired in Tyk2^−/− DCs. (A) Isolated CD11c⁺ DCs from WT, Tyk2^−/−, or Stat4^−/− splenocytes were cultured with IL-12 (20 ng/mL) or IL-23 (20 ng/mL) for 3 days. The amounts of IFN-γ in the supernatants were measured by ELISA. Data are means (± SD) from 5 independent experiments. ND indicates not detectable. *Significantly different from the corresponding mean values of WT DCs, *P < .01. (B) Isolated CD11c⁺ DCs from WT or Tyk2^−/− splenocytes were cultured with CpG ODN for 3 days. After cells were washed and rested in fresh medium for 12 hours, cells were stimulated with IL-12 (20 ng/mL) for 3 days. The amounts of IFN-γ in the supernatants were measured by ELISA. Data are means (± SD) from 4 independent experiments. *Significantly different from the corresponding mean values of WT DCs, *P < .05. (C) Isolated CD11c⁺ DCs from WT or Tyk2^−/− splenocytes were cultured with IL-12 (20 ng/mL) for 72 hours with monensin added for the final 4 hours. Cells were stained with anti-CD11c FITC and anti-CD8 PE and then the production of IFN-γ was evaluated by intracellular staining by FACS. Representative FACS profiles of CD8 versus IFN-γ gated on CD11c⁺ cells are shown (n = 4, each).