Figure 5

Tissue damage and inflammatory infiltrates in influenza infected Rag2^-/-mice. Lung tissue sections from female wild type or Rag2^-/-mice infected with 2 × 10³ FFU PR8 were prepared at the days indicated and stained with hematoxylin and eosin. (A) Wild type mice day 4 p.i.: severe bronchial epithelial necrosis, mild to moderate peribronchial and interstitial lymphocytic and histiocytic infiltrates with few neutrophils. (B) Rag2^-/-mice day 4 p.i.: severe bronchial epithelial necrosis, moderate peribronchial and interstitial neutrophilic infiltrates with few lymphocytes. (C) Wild type mice day 6 p.i.: severe bronchial epithelial necrosis, marked perivascular lymphocytic infiltrates and mild lympho-histiocytic interstitial pneumonia. (D): Rag2^-/-at day 6 p.i.: moderate bronchial epithelial necrosis, severe peribronchial, interstitial and luminal neutrophilic infiltrates. (E) Wild type mice at day 10 p.i.: minimal bronchial epithelial necrosis, severe peribronchial lymphocytic infiltrates and moderate lympho-histiocytic interstitial pneumonia with moderate hyperplasia of type 2 alveolar epithelial cells. (F): Rag2^-/-mice at day 10 p.i.: severe bronchial epithelial necrosis, severe peribronchial, interstitial and luminal neutrophilic infiltrates, mild hyperplasia of type 2 alveolar epithelial cells. Scale bar is 200 μm.