Fig 5. Effect of mutant S100A8/A9 protein application on antibacterial responses and Zn²⁺ levels in lungs of S. pneumoniae-infected S100A9 KO mice.

S100A9 KO mice were orotracheally infected with S. pneumoniae and therapeutically treated with mutant S100A8/A9 protein or vehicle i.p., as indicated. (A) Zn²⁺ levels in lungs of S. pneumoniae-infected S100A9 KO mice treated with mutant S100A8/A9 protein or vehicle i.p. at 8 hours post-infection. (B) Bacterial loads in lung at 8 hours after pneumococcal challenge. (C) Numbers of recruited neutrophils in BAL fluids of mutant S100A8/A9 or vehicle treated S. pneumoniae-infected S100A9 KO mice at 8 hours post-infection. Values are shown as mean ± SD of n = 7–9 mice per time point and treatment group and are representative of two independent experiments. **p ≤ 0.01; ***p ≤ 0.001 compared to vehicle treated mice (Mann-Whitney U test).