IFN-γ^−/− donor CD4⁺ T cells induced preferential tissue damage in lung and skin in association with augmented differentiation of Th17 and Th2 cells. (A-C) Percent survival, percentage of mice with diarrhea, and body-weight change after HCT. There were 12 mice in each group, combined from 3 replicate experiments. (D-E) Hematoxylin and eosin (H&E) staining of colon, liver, lung, and skin sections of recipients 20 to 25 days after HCT and mean ± SE of histopathology scores (n = 12). (F) Mean ± SE of T-bet, Gata-3, and RORγt expression in sorted splenic CD4⁺ T cells (purity > 90%) from recipients given IFN-γ^−/− donor cells 5 days after HCT (n = 4). Relative gene expression levels were normalized within each sample to GAPDH and were presented relative to the expression of WT control. Data are representative of 2 replicate experiments. (G) Intracellular cytokine profiles of splenic CD4⁺ T cells 7 days after HCT. Gated CD4⁺ T cells are shown in CD4 versus cytokines. A representative of 4 replicate experiments is shown. (H) Seven days after HCT, sorted H-2b⁺CD4⁺ T cells from the spleen of recipients given WT or IFN-γ^−/− donor cells were restimulated with plate-bound anti-CD3/CD28. Mean ± SE of supernatant cytokines 24 hours after culture. These were 4 samples in each group, combined from 2 replicate experiments.