Figure 2.

Protective efficacy of the adjuvanted vaccines in the immunized mice after the lethal influenza virus challenge. Immunized BALB/c mice (n = 10) were challenged with a lethal dose of homologous A/PR8 (1.5 × LD₅₀) after 3 weeks of boost immunization. Body weight (BW) (A) and survival rates (B) of the challenged mice (n = 5) were measured for 14 days after viral infection, and percentages of changes were calculated based on BW at day 0. For statistical analysis, two-way ANOVA and Tukey’s post-multiple comparison tests were performed. *p < 0.0332, and ****p < 0.0001 between iPR8 and iPR8 + MPL + Poly I:C groups. (C) Lung homogenates (n = 5) were harvested at day 7 post infection, and lung viral titers were measured. Statistical analysis was performed using one-way ANOVA and Tukey’s post-multiple comparison tests. **P < 0.0021, ***P < 0.0002, ****P < 0.0001. All results were shown in mean ± standard deviation (SD) with individual dots.