Neutralizing IFN-γ in recipients given IL-17^−/− donor cells ameliorated acute GVHD. (A,B) BALB/c recipients given spleen cells (2.5 × 10⁶) and TCD-BM cells (2.5 × 10⁶) from IL-17^−/− donors were injected intraperitooneally with anti–IFN-γ mAb or control rat IgG (0.5 mg/mouse) on days 0, 5, 10, and 15 after HCT. Body weight change and survival curves are shown. There were 8 mice in each group; 2 replicated experiments were combined. (C) Means (± SE) of serum levels of IFN-γ and TNF-α of the above recipients 5 days after HCT. (D) Means (± SE) of donor T-cell yield in liver of recipients treated with anti–IFN-γ or rat IgG 5 days after HCT. There were 4 recipients in each group. (E) MLN cells of the recipients treated with anti–IFN-γ or rat IgG were stained for H-2^b (donor marker), CD4, CD8, and CCR5 or isotype control 5 days after HCT. Gated on H-2^b+CD4⁺or CD8⁺ T cells, a histogram of anti-CCR5 (solid line) and isotype control (shaded area) is shown. One representative of 4 recipients in each group is shown. Means (± SE) of the CCR5⁺CD4⁺ T cells in recipients treated with anti–IFN-γ or rat IgG are 15.4% (± 1.5%) or 32.3% (± 1.4%). Means (± SE) of the CCR5⁺CD8⁺ T cells in recipients treated with anti–IFN-γ or rat IgG are 28.4% (± 1.1%) or 65.3% (± 5.2%). (F) Means (± SE) of chemokine expression levels in liver of the recipients treated with anti–IFN-γ or rat IgG 5 days after HCT. Relative gene expression levels were normalized within each sample to the house keeping gene GAPDH and were presented relative to the expression in synergic HCT recipients. There were 4 mice in each group.