Figure 7.

N-Bac and S-Bac as potential COVID-19 vaccines. (A) Immunization schedule of N-Bac and S-Bac in mice. Serum samples of each mouse were collected at weeks four and six after primary immunization. (B, C) Indirect ELISA against purified N (B) or S1 (C) to determine the levels of specific anti-N and anti-S1 IgG antibody in mice immunized with DPBS (n=5), EG-Bac (n=5), N-Bac (n=10), or S-Bac (n=10). Mann–Whitney test: *P< 0.05; **P<0.01; ***P<0.001. (D) Neutralizing activities of mouse sera (week six, n=5) against SARS-CoV-2 pseudovirus. Percent inhibition of pseudovirus infection of HEK293T cells was determined relative to the virus without serum addition. Mean values ± SD from three independent experiments are shown.