IFN-γ-mediated protection prevents IL-17-mediated mortality. (A) Number of CD4+ T cells in the infiltrating population and distribution of Thy1.1 positive cells measured by flow cytometry at day eight p.i. Data represent means (±SD) of twelve mice per group combined from three separate experiments. (B) IL-17 mRNA expression determined by quantitative real-time PCR in infected SCID recipients of WT, WT/GKO or GKO CD4+ T cells. Data represent the mean of two experiments with n = 4 in each group per experiment. (C) Splenocytes of immunized GKO donors cultured in the presence of JHMV with or without recombinant IFN-γ (10 ng/ml) for six days and restimulated four hours with PMA/Ionomycin. Intracellular cytokine expression on CD4+ T cells analyzed by flow cytometry using FITC-IFN-γ, PE-IL-17 and the corresponding isotype controls. Dot plots are representative of duplicates from two separate experiments. (D) Survival of infected SCID recipients of WT/GKO (n = 6), WT/GKO + anti-IFN-γ mAb (n = 8) and GKO (n = 4) CD4+ T cells assessed daily. Data are representative of two separate experiments.