FIG 5.

Viral replication and type 1 IFN expression in neonatal ddY mice after intracerebral inoculation of the original (AM) or mouse-passaged (AM-5Cb) SAFV-3 strain. Virus titers (A) and the numbers of viral RNA copies per mouse (B) were measured in the cerebrum/brainstem and cerebellum on days 3, 7, and 21 p.i. with the SAFV-3 strains (10⁴ CCID₅₀s/10 μl; n = 4 per day). The dotted line in panel A represents the viral titer detection limit. The expression levels of mouse type 1 IFN-α4 and -β (C) were determined on days 3, 7, and 21 p.i. (n = 4 per day). The brains of mock-infected mice were used as a negative control. The numbers of viral RNA copies and type 1 IFN mRNA copies are expressed relative to the number of mouse beta-actin RNA copies. **, P < 0.01; ***, P < 0.001; one-way ANOVA.