Figure 2.

S proteins from SARS-CoV-2 variants drive entry into human cell lines

(A) Directed expression of SARS-CoV-2 S proteins (SARS-2-S) in A549-ACE2 cells leads to the formation of syncytia. S protein expression was detected by immunostaining using an antibody directed against a C-terminal HA-epitope tag. Presented are the data from one representative experiment. Similar results were obtained in four biological replicates.

(B) The S proteins of the SARS-CoV-2 variants mediate robust entry into cell lines. The indicated cell lines were inoculated with pseudotyped particles bearing the S proteins of the indicated SARS-CoV-2 variants or wild-type (WT) SARS-CoV-2 S. Transduction efficiency was quantified by measuring virus-encoded luciferase activity in cell lysates at 16–20 h post transduction. Presented are the average (mean) data from six biological replicates (each conducted with technical quadruplicates). Error bars indicate the standard error of the mean (SEM). Statistical significance of differences between WT and variant S proteins was analyzed by one-way analysis of variance (ANOVA) with Dunnett’s posttest (p > 0.05, not significant [not indicated]; p ≤ 0.05, *; p ≤ 0.01, **; p ≤ 0.001, ***). See also Figure S1.