TH17-mediated pathologic conditions are independent of IFN-γ. TH17 cells (5 × 10⁶) from WT (n = 8) or IFN-γ^−/− mice (n = 7; differentiated as in Figure 1) were transferred with T cell–depleted bone marrow cells into lethally irradiated B6D2 recipients. Animals were monitored for survival (A) and signs of GVHD (B). (C) Comparison of pathologic skin lesions in recipients of 5 × 10⁶ IFN-γ^−/− TH17 cells (left animal) versus recipients of WT TH17 cells (right animal) at day 25 after transplantation. IFN-γ^−/− TH17 cells were transferred into irradiated B6D2 recipients. Eight days after transplantation, lymphocytes were extracted from the lung and stimulated as in Figure 1 followed by intracellular cytokine staining for IL-17 (D) and IL-17F (E). Plots derived from CD4⁺ gate.