Figure 5.
Heterologous virus challenge. Mice were challenged with 2 × LD50 of mouse-adapted Philippines (Phi) viruses 4 weeks postimmunization. (A, B) Morbidity and mortality. (C) Phi virus-specific antibody levels in immune sera. (D, E) HAI titers and neutralizing antibody titers. (F) Antibody levels in nasal washes and BALF. (G) Phi-specific IFN-γ-secreting splenocytes. Data are presented as mean ± SEM (n = 5 for A–E and n = 3–4 for F,G). One-way ANOVA then Tukey’s multiple comparison tests were employed for statistical significance analysis (*p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001; ns, p > 0.05).