Figure 3

Histopathological finding in lungs of mice infected with S. pneumoniae (with or without mucin) or instilled with sterile mucin. Lung biopsies stained with hematoxylin-eosin and observed under optic microscopy with magnification of x4 (panels a and c), x10 (panels b and d) and x40 (panels e and f). Panels a and b correspond to mice infected with an inoculum of S. pneumoniae INS-E611 grown in Todd-Hewitt broth (THB) without mucin, panels c and d correspond to animals infected with mucin-supplemented inoculum and panels e and f show the lungs from uninfected mice instilled with sterile mucin. Abbreviations: necrosis (N), atelectasis (T), Gram positive bacteria (B), edema (E) and lymphocytes (L).