FIG 6.

Neutralizing activity of various human, cat, and rabbit sera against pseudotyped viruses carrying SARS-CoV-2 parental or single mutant S using cells expressing human ACE2. CRFK cells expressing human ACE2 were infected with pseudotyped viruses and tested for neutralizing activity against various human (A, B, and C), cat (D, E, and F), and rabbit (G, H, and I) sera. Following incubation of the cells for 48 h, cells were lysed, and the relative luminescence units were measured. Each bar indicates the mean and the standard error of the means. PA indicates parental pseudotyped virus.