FIG 1.

IL-12p35-deficient mice have increased susceptibility to respiratory MRSA infection. (A) WT and IL-12p35^−/− mice were treated i.n. with either 1 μg of IL-12 or PBS vehicle and then 24 h later were i.n. infected with 1 × 10⁸ CFU of MRSA. Survival was monitored every 12 h for 7 days. Each group contained 10 mice, and the results of two independent experiments were pooled. *, P < 0.05 as determined by log rank test. Bacterial loads (B) and cytokine levels (C) in lung and spleen homogenates and in serum were determined 24 h after MRSA infection. Each bar represents the mean ± standard error of the mean (SEM) of the results from 4 to 19 mice/group. The data were pooled from three independent experiments. Statistical analysis was performed by using the Mann-Whitney U test. *, P < 0.05; **, P < 0.01; ***, P < 0.001.