Fig. 2.
Immunogenicity of rMeVs expressing SARS-CoV-2 antigens in cotton rats. (A) Immunization schedule in cotton rats. Cotton rats (n = 5) were inoculated subcutaneously with phosphate-buffered saline or 4 × 105 PFU of each of the rMeV-based vaccine candidate. Four weeks later, cotton rats were boosted with 106 PFU of each virus. Serum samples were collected at weeks 4, 6, and 8 for antibody detection. (B) Measurement of SARS-CoV-2 S-specific antibody by ELISA. Highly purified preS protein was used as the coating antigen for the ELISA. Dotted line indicates the detectable level at the lowest dilution. (C) Measurement of SARS-CoV-2–specific neutralizing antibody. Antibody titer was determined by a plaque reduction neutralization assay. Dotted line indicates the detectable level at the lowest dilution. Data are expressed as the geometric mean titers (GMT) of five cotton rats ± SD. Data were analyzed using two-way ANOVA (*P < 0.05; ***P < 0.001; ****P < 0.0001).