FIG 2.

IL-12 treatment improves protection against respiratory MRSA infection. WT mice were treated i.n. with either 1 μg of IL-12 or PBS vehicle 24 h before i.n. MRSA infection. (A) Treated mice were challenged i.n. with either 1.5 × 10⁸ (left) or 2.5 × 10⁸ (right) CFU. Survival was monitored every 12 h for 7 days. Each group contained 10 to 15 mice, and the results of three independent experiments were pooled. *, P < 0.05; **, P < 0.01 as determined by a log rank test. (B) Lung and spleen bacterial levels 4 and 24 h after challenge i.n. with 1 × 10⁸ CFU of MRSA. Each symbol represents an individual mouse, and the line indicates the mean. Data were pooled from three independent experiments. Statistical analysis was performed by using the Mann-Whitney U test. ***, P < 0.001.