FIG 5.

Neutralizing antibody responses generated by DB1-QUAD to a panel of recombinant RSVs. To assess immunogenicity, groups of 5 BALB/c mice were inoculated i.n. with either MEM (mock infection) or 10⁶ FFU of mKate2-labeled A2-line19F, DB1, or DB1-QUAD. Sera were collected and pooled on days 0, 28, 56, and 100 p.i., and neutralizing antibody responses to a panel of recombinant mKate2-labeled RSVs were measured by FFU reduction assays. The data represent mean 50% effective concentrations (EC₅₀) plus SD of two experimental replicates of pooled sera of 5 mice per group. *, P < 0.05; ***, P < 0.0005; ****, P < 0.00005 by two-way ANOVA with Tukey's multiple-comparison test.