3.3 Protective efficacy of Cap-3M2e VLPs against IAV

All mice immunized with Cap VLPs died by 4 to 6 dpc with the highest virus titers in lungs and over 25% body weight loss (Fig. 4). The protective efficacy of groups Cap-hsaM2e VLPs and Cap-hasM2e VLPs were the highest among all groups, and protected all mice from lethal infection when challenged with 10 × LD50 A/Puerto Rico/8/1934 (H1N1) (Fig. 4a-4c). Similarly, the Cap-shaM2e VLPs and Cap-sahM2e VLPs groups showed the highest protection efficacy, and conferred complete protection against 10 × LD50 of A/swine/Zhucheng/90/2014 (H1N1) (Fig. 4d-4f). The Cap-ahsM2e VLPs and Cap-ashM2e VLPs groups demonstrated the lowest body weight loss, mortality rate and lung virus titers among all groups, when challenged with 40 µL 109 TCID50/mL of A/chicken/Guangzhou/GZ/2005 (H9N2) (Fig. 4g-4i).