Figure 6.

Quantification of the relative infectivity of Ha-CoV-2 variants and their responses to neutralizing antibodies

(A and B) Ha-CoV-2(Luc) particles bearing the G614 mutation S or the parent D614 S were assembled and analyzed for the incorporation of S and N in virions.

(C) Ha-CoV-2(Luc)(G614) or Ha-CoV-2(D614) was used to infect target cells, and Luc expression was quantified at 5 h. An equal level of viral particles was used for infection. Infection and luciferase assays were performed 3 times, and the mean and SD are shown.

(D) A panel of S protein mutants from SARS-CoV-2 variants were used to assemble Ha-CoV-2(Luc) particles and then to infect target cells. The relative infectivity was quantified and normalized with the genomic RNA copies of individual Ha-CoV-2(Luc) variants. Wild type (WT) refers to Ha-CoV-2 derived from the original SARS-CoV-2 strain. Infection and luciferase assays were performed 3 times, and the mean and SD are shown.

(E and F) Quantification of anti-serum against Ha-CoV-2(Luc) and its variants. Convalescent plasma from an infected blood donor, before and after one-dose vaccination, was quantified for inhibition of Ha-CoV-2(Luc) infection. Neutralization activities were quantified by luciferase assay at 12 h post infection. The IC₅₀ was calculated using the relative percentage of infection versus serum concentration (E). The post-vaccination anti-serum was similarly quantified for the inhibition of Ha-CoV-2(Luc) variants (F).