Fig. 4.

Effect of IFN-γ treatment on lung pathology. WT and TRIF mutant mice were infected with about 10⁴ CFU K. pneumonia; 50 ng recombinant IFN-γ or vehicle was administered intranasally 30 min before infection and 24 h afterwards. Mice were sacrificed after 48 h of infection. Representative lung histology of WT mice treated with vehicle (a), WT mice treated with rIFN-γ (b), TRIF mutantmice treated with vehicle (c) and TRIF mutantmice treated with rIFN-γ (d). HE. a-d Upper panel: arrows indicate signs of bronchitis. ×10. Lower panels: stars indicate pleuritis. ×20. Representative lung histology (Ly-6 staining, indicating neutrophils) of lungs of WT mice treated with vehicle (e), WT mice treated with rIFN-γ (f), TRIF mutantmice treated with vehicle (g) and TRIF mutantmice treated with rIFN-γ (h). ×10.