FIG 3.

S. pneumoniae and IAV stimulate IFN-I signaling at 48 h p.i. WT and Ifnar1^−/− pups were infected i.n. with 10³ CFU the S. pneumoniae T4 or T4Δply mutant, 250 PFU IAV, or T4 plus IAV; mock-infected mice received PBS. RNA was isolated from URT lavages 48 h p.i. and analyzed by qRT-PCR. S. pneumoniae-infected mice showed significantly increased expression of the ISGs Ifit2, Mx1, and Oasl2 compared to that of mock-infected mice. This increased expression was seen only in WT and not Ifnar1^−/− mice. The stimulation of ISGs by S. pneumoniae was ply dependent. Gene expression data are log₁₀ transformed; each symbol represents the value from an individual pup. Comparisons (Mann-Whitney test) are to mock-infected mice of the respective genotype. n ≥ 5 pups/group. ns, not significant; *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001.