Recombinant SARS-CoV-2 spike S1-Fc fusion protein induced high levels of neutralizing responses in nonhuman primates

A vaccine candidate against SARS-CoV-2, purified spike protein fused with Fc region of human IgG1 was prepared. The N-terminal half of spike protein S1 that contains receptor-binding domain is expressed as the fusion protein with Fc in CHO-K1 cell line, which produce this protein into culture medium.  Animals including mice, rabbits and macaques were inoculated with purified protein combined with several adjuvants. The production of neutralizing antibodies against SARS-CoV-2 in the sera of these animals was confirmed.