Figure 1.

Animals with targeted gene deletion in the IL-12, IL-17, and IL-23 signaling pathways demonstrate increased mortality during intrapulmonary K. pneumoniae infection. (A) WT C57BL/6, IL-23 p19^−/−, IL-12 p35^−/−, IL-12 p40^−/−, or IL-17R^−/− mice were challenged with 10⁴ CFU intratracheal K. pneumoniae and survival was recorded every 12 h (n = 16–20 per group). IL-12 p40 knockout mice showed the greatest susceptibility to infection (*P < 0.01 compared with C57BL/6 [log rank test]). Survival differences between IL-23 p19^−/−, IL-17R^−/−, and IL-12 p35^−/− mice were not statistically significant. (B) WT and p19^−/− mice were also challenged with a lower dose (10³ CFU) of bacteria, demonstrating significant mortality in p19^−/− mice to a sublethal dose of K. pnuemoniae (*P < 0.01 compared with WT mice; n = 10 per group).