Protection against Multiple Subtypes of Influenza Viruses by Virus-Like Particle Vaccines Based on a Hemagglutinin Conserved Epitope

Figure 4

Protection of mice against lethal challenge with homologous virus after pretreatment with anti-LAH-HBc serum. Serum collected from mice immunized with LAH-HBc together with CTB^* (designated as LAH-HBc plus CTB^* group), from sublethal infection (designated as 0.5 × LD₅₀ of PR8 group) or from mice treated with PBS (designated as PBS group), was passively transferred through caudal vein to naïve BALB/c mice (10 mice in each group), respectively. The LAH-HBc plus CTB^* group, 0.5 × LD₅₀ of PR8 group, PBS group, and blank control group were all challenged with 5 × LD₅₀ of PR8 in 12 hours and monitored for survival rates (a) and weight loss (b). ^*Significant difference compared to the control group ().

(a)

(b)