FIG 5.

In vivo replication, bioluminescence, and virulence of rPB2-MA9 and rPB2-MA9/PA-D479N in DBA/2 mice. Groups of 5 DBA/2 mice were intranasally inoculated with 30 μl PBS containing 750 PFU of virus, and experiments were repeated. (A and B) Body weight changes (A) and survival (B) were observed for 14 days in intact mice. (C) Virus tissue titers in nasal turbinates, trachea, and lungs were measured 4 dpi. (D) Noninvasive bioluminescence intensities in the lungs were observed for 4 days in intact mice. The reported values are means and standard deviations. (A and B) The data are cumulative from three independent experiments (n = 15). (C and D) The data are from two experiments (n = 10). *, P < 0.05; **, P < 0.01; ***, P < 0.001.