Figure 4.

Protective efficacy of aerosolized YF-17D in A129 mice. (A) Survival curve of the immunized mice (n = 5). Briefly, the immunized mice were challenged with 1 × 10³ PFU of YF-17D via the i.c. route at 28 days after immunization and monitored for clinical symptoms and mortality. Kaplan-Meier survival curves were analyzed by a log-rank test (**, p < 0.01). (B) Viral loads in serum were measured at 1, 3, and 5 days after challenge by RT-qPCR assays. Viral load was expressed as RNA copies per milliliter. Dotted lines indicate the limit of detection. (C) Tissue distribution in mice (n = 3) at 5 days after YF-17D challenge. Dotted lines represent limits of detection. The data were shown as mean± SD. Significance was calculated using one way ANOVA (n.s., not significant; *, p < 0.05; ***, p < 0.001; ****, p < 0.0001).