FIG 5.

Ferret immune responses to mutant CDVs. (A) Relative levels of type I IFN and Mx-1 message in PBMCs isolated at days 3 and 7 after infection of animals. Symbols represent relative fold change in mRNA level normalized to uninfected naive controls (day 0) for each biological replicate. Horizontal lines and error bars show means and SEM, respectively; t tests were used for pairwise comparisons, and one-way ANOVA with Sidak's post hoc test was applied to Mx-1 day 7 fold change analysis. (B) Neutralizing antibody responses. Titers are shown as the reciprocal of the highest dilution in which CPE was observed. Symbols represent individual biological replicates, and lines connect sample means; two-way ANOVA with Sidak's post hoc test (comparison of the recCDV NΔ425–479- and recCDV NΔ441–479-infected groups only) was used. (C) Challenge of surviving animals from Fig. 4 with 2 × 10⁵ TCID₅₀ units of standard recCDV-5804PeH at day 49 postinfection. Survival curves are shown for rechallenged and CDV-naive ferrets (before infection with recCDV NΔ425–479, n = 3; recCDV NΔ441–479, n = 4; naive, n = 4). (D) Cell-associated viremia titers in rechallenged animals. Symbols represent TCID₅₀ for each biological replicate, and lines connect sample means; two-way ANOVA with Tukey's post hoc test was used. (E) Lymphopenia in rechallenged animals. Symbols represent leukocyte counts for each biological replicate, and lines connect sample means; two-way ANOVA with Tukey's post hoc test was used.