Fig. 1.

Staphylococcus aureus pneumonia and alveolar pathology in C57/BL mice. A: hematoxylin and eosin (H&E)-stained sections of inflation-fixed lung in C57/BLWT mice at 0, 1, 2, and 3 days postinoculation with 5 × 10⁸ colony-forming units (CFU) S. aureus (200 ×). The inflammatory response is markedly enhanced at day 1. In that photomicrograph, loss of alveolar membrane integrity is indicated by red blood cell and plasma leakage (short arrow) and alveolar neutrophil infiltration (long arrow). B: bronchoalveolar lavage (BAL) fluid cell number (cells/ml × 10⁵) plotted against days postinfection. BALF cell number increased significantly at day 1 (*P < 0.05) and subsided by day 2. C: total BAL fluid protein concentration plotted against days of infection. Protein increased by day 1 and subsided by day 2. Bars are means ± SE for n = 6/group; *P < 0.05 vs control by one-way ANOVA.