Type I IFN signaling is indispensable for IFN-γ, IL-12 and CXCL10 induction in K. pneumoniae-infected lungs.

WT and Ifnar1-/- mice were infected intranasally (5 x 104 CFU of K. pneumoniae) for 12 (A, B) or 48 (C) h, or treated with PBS, and gene expression was determined by qPCR normalized to Hprt. (A) Mx1, Ifit1 and Isg15 mRNA levels in lungs. (B, C) Ifng, Il12b, Cxcl10, Tnf and Il10 mRNA levels in lungs. Statistical evaluation: unpaired Student’s t test; error bars, mean ± SEM (n > 3); *, P < 0.05; **, P < 0.01; ***, P < 0.001; ns, not significant.