Fig. 3: Virological features of BA.2.86/JN.1 and EG.5.1/HK.3 in vitro.

a SARS-CoV-2 spikes mediated cell-cell fusion in vitro. 293T cells (effector cells), which were co-transfected with the indicated spike and GFP1-10, were co-cultured with 293T cells co-transfected with hACE2 and GFP11 (target cells) (n = 10). The cells were fixed after 24 hours of incubation. GFP signal intensity was measured by ImageJ. The n number represents biological repeats. b Entry efficiency of pseudoviruses in cell lines. Pseudoviruses entry were quantified by measuring the luciferase signal at 24 h post-transduction (n = 6 for B.1 and n = 7 for other variants). Fold change in the luciferase signal was normalized to the mean luciferase readout of BA.2-spike pseudoviruses. The n number represents biological repeats. c Plaque size of Omicron BA.2, BA.2.86, JN.1, XBB.1, EG.5.1, and HK.3 in VeroE6 cells. VeroE6 cells were challenged with 60 PFU of Omicron BA.2, BA.2.86, JN.1, XBB.1, EG.5.1, and HK.3. The infected cells were fixed with 4% paraformaldehyde at 96 and 120 hpi and stained with crystal violet. Plaque size was measured by Adobe Photoshop (n = 10). The n number represents biological repeats. d Protease usage by pseudoviruses in cell lines. VeroE6-TMPRSS2, Calu3, Caco2, and 293T cells were pre-treated with 10 μM Camostat or E64D for 2 h, followed by transduction with B.1-, BA.2-, BA.2.86-, JN.1-, XBB.1-, EG.5.1-, and HK.3-spike pseudoviruses. At 24 h post-transduction, the level of pseudovirus entry was quantified by measuring the luciferase signal. The fold change was normalized to the mean luciferase readout of cells treated with DMSO for each variant (n = 6). The n number represents biological repeats. Data represent mean ± SEM. Statistical significance in (a–d) was determined with one-way ANOVA with post hoc Tukey’s multiple comparisons test. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. NS is not statistically significant. Source data are provided as a Source Data file.