To characterize pneumococcal meningitis, leukocyte recruitment was analyzed in brains of mice with meningitis 48 h post infection with TIGR4 (n = 3–6 mice/group in four independent experiments) (Figures 3A,B) and the source of IFN-γ was investigated by flow cytometric analysis (Figure 4). This evidence concerns the gene IFNG and pneumococcal meningitis.