Figure 4

Brain pathology of mice with pneumococcal meningitis. Nissl staining of the cortex of mice infected with S. pneumoniae, showing extensive leptomeningeal inflammatory infiltrate (A; 100× magnification), perivascular lymphocytic cuffing (B; 100× magnification), perivascular lymphocytic infiltration combined with bacterial overgrowth (C; 200× magnification) and further bacterial overgrowth combined with perivascular necrosis (D; 100× magnification). Iba-1 immunohistochemistry revealed microglial activation (E; 100× magnification). Hematoxylin and eosin staining showed subarachnoidal and cortical hemorrhages (F; 100× magnification).