Figure 3. Improved resistance of T‐bet‐deficient mice against post‐influenza bacterial superinfection.

• A
  Model of post‐influenza bacterial infection illustrating infection with sub‐lethal dose of influenza virus (25 pfu) followed by sub‐lethal dose of secondary bacterial challenge (Streptococcus pneumoniae serotype 19F, 2 × 10⁵ cfu) 7 days later. Where appropriate, mice lungs were analysed at days 0, 1 and 3 post‐secondary bacterial infection, corresponding to days 7, 8 and 10 post‐influenza virus infection, respectively.
• B–G
  Mice were superinfected as described in (A). (B) Survival of mice following bacterial superinfection. See also Fig EV3B. (C) Pneumococcal cfu in BAL of mice. See also Fig EV3C. (D) Absolute immune cell counts in lungs, assessed by flow cytometry. See also Fig EV3D. (E) Pneumococcal cfu in BAL of mice 12 h after infection with 2 × 10⁵ cfu of S. pneumoniae serotype 19F alone (−Flu) or following influenza virus infection (+Flu). See also Fig EV3C. (F) Pneumococcal cfu in BAL 36 h after infection of naïve mice with 2 × 10⁵ cfu of S. pneumoniae serotype 19F alone. (G) Absolute neutrophil and eosinophil cell count in lungs infected as described in (E), assessed by flow cytometry.

Data information: Data from (B) are combined from two independent experiments, n = 13 mice per experimental group. Data from (C–G) are representative of at least two independent experiments with 3–5 (C, D and G) or 5–7 (E and F) mice per experimental group. All data are represented as mean ± SEM. Statistical significance was determined by log‐rank test in (B), unpaired Student's t‐test in (D) and (G) and Mann–Whitney U‐test in (C) and (E). n.s., not significant.