Fig. 2.

BALB/c mice immunized with nanoparticle vaccines produced SARS-CoV-2 ECD-S1- and RBD-specific antibodies. (A) The immunization protocols. Mice were immunized with vaccines administered via subcutaneous or oral routes. (B) and (C) Detection of ECD-specific IgG with respect to different routes of serum administration on days 14 and 35. (D) and (E) Detection of S1-specific IgG with respect to different routes of serum administration on days 14 and 35. (F) and (G) Detection of RBD-specific IgG in different routes of administration of sera from Days 14 and 35. The experiment was repeated twice, with six mice per group in each experiment; error bar, SEM; *** p < 0.001.