Figure 6

Growth, virulence and viral tropism are increased by 103L and 106I NS1 mutations in rWSN-Ck/Bj-NS. A. Groups of 5 BALB/c mice were infected intranasally with 10⁶ pfu with the different rWSN viruses. Survival was monitored for 14 dpi. B. Groups of 5 BALB/c were infected intranasally with 5 × 10³ pfu with the rWSN viruses. Lungs were collected at days 1, 3, 5 and 7 pi, sonicated and the viral titer was assessed by plaque assay. Values are shown as average of 2 replicates +/- standard error for each value. C. BALB/c mice were infected intransally with 10⁵ pfu of rWSN-Ck/Bj-NS-L103F + I106M and lungs were collected 2 dpi. The lungs were inflated and fixed with 3.7% formaldehyde and lung sections were stained with anti-WSN antibody. The bronchiolar regions are indicated by an arrow. D. rWSN-Ck/Bj-NS-103L + 106I infected lungs. Statistical analysis was performed using the parameters of paired and two-tailed student's t-test with probability ≤ 0.01.