Figure 1.

Replication efficiency of viral chimeras. (A) Duplicate wells of BV2 cells were infected with MNV1, CR6, WU23 or the indicated chimeric virus at MOI 0.05. Virus titers were determined by TCID₅₀ assay on culture supernatants. Three independent experiments were performed. P values were determined using ANOVA with Dunnett’s multiple comparisons test by comparing each chimeric virus to its respective parental virus. (B) Groups of P3 BALB/c neonatal mice were inoculated with 10⁷ TCID₅₀ units of MNV1, CR6, WU23 or the indicated chimeric virus. At 2d, viral titers were determined in the distal small intestine by plaque assay. At least five mice from at least two independent litters per condition were analyzed. P values were determined using ANOVA with Sidak’s multiple comparisons test by comparing each chimeric virus to its respective parental virus. *P < 0.05, **P < 0.01, ****P < 0.0001.