2.3 Immunization and
challenge
Female BALB/c mice (6-8 weeks old) were randomized into groups. Six
groups were subcutaneously immunized with 26.6 µg (100 µL) candidate
vaccines, respectively. The Cap VLPs group (20 µg, Cap molar equivalent)
is serves as positive control. The Carbopol 971P as adjuvant
(Ding et al., 2017). Booster immunization
was performed at the 21 and 42 days post initial immunization (dpi).
Serum samples were collected at 63 dpi and stored at -20 °C until use.
Mice in each group were divided into three groups (n=9). Mice were
lightly anesthetized and intranasally challenged with lethal dose
humans, swine and avian IAV at 64 dpi, respectively. Survival rates and
body weight loss were monitored daily for 14 days post challenge (dpc).
Mice were humanely euthanized if weight loss of ≥ 25%.