FIG 6.

Effects of PA mutations at positions 343 and 347 on virus titers in the organs of mice infected with QT1728 or TY31 virus. (A to H) Six mice per group were inoculated intranasally with 10³ PFU of wild-type or mutant QT1728 (A to D) or TY31 (E to H) viruses. Three mice per group were euthanized on day 3 and day 6 postinfection, and lungs, nasal turbinates, brains, spleens, and kidneys were collected for virus titration in MDCK cells. Each symbol represents the value for an individual mouse. Weight change and virus titer data are presented as mean values with standard deviations. The virus titer data shown in panel A are identical to those in Fig. 2E; they are presented again to aid in the comparison of the wild-type and mutant viruses.