FIG 5 .
Virulence of A. fumigatus mutants in a murine infection model. (A) Survival of mice infected with mutant strains was plotted using Kaplan-Meier curves and analyzed using a log rank pairwise comparison (P < 0.05). A total inoculum of 4 × 106 conidia was delivered intranasally to mice immunosuppressed with cyclophosphamide and triamcinolone acetonide, and survival was scored daily for 14 days. Mortality caused by all mutant strains with the exception of the T333A strain was not statistically different from that with the WT control strain, while the T333A strain was similar to the ΔpkaC1 strain. (B) Lung histopathologic examination at 3 days postinfection. Gomori’s methenamine silver staining (top row) showed appreciable hyphal growth only in the animals infected with the PkaC1-GFP positive-control strain and the T333E mutant strain. Hematoxylin and eosin staining (bottom row) showed inflammation and tissue damage in these same strains. Tissue infected with the other mutant strains displayed the same lack of hyphal growth and tissue damage as that observed in the ΔpkaC1 strain-infected negative control. Magnification, ×10.