FIG 6.

Adaptive immune responses to S. pneumoniae are impaired in mir155KO mice. Over the course of colonization, the frequencies of IFN-γ (A)- and IL-17A (C)-expressing CD3⁺ CD4⁺ splenocytes were enumerated by intracellular cytokine staining (n = 4 to 10 per group per time point) and the secretion of IFN-γ (B) and IL-17A (D) by splenocytes following 6 day of exposure to S. pneumoniae was measured by ELISA (n = 4 or 5 per group per time point). Levels of IL-17A and IFN-γ mRNAs in the nasopharynx (E) over the course of colonization (n = 3 or 4 per group per time point) and serum IgG levels (F) at day 21 postcolonization (n = 4 to 6 per group per time point) were measured. Representative flow cytometry histograms (left) and IgG mean fluorescent intensity (MFI) levels (right) are presented. Statistical significance was determined by Wilcoxon rank sum test. ***, P < 0.001; **, P < 0.01; *, P < 0.05. D0, uninfected; D7, D14, and D21, days 7, 14, and 21 postcolonization, respectively.