Fig. 2: Replication ability and entry phenotype of SARS-CoV-2 in Calu-3 cells.

a Replication kinetics in cells infected with viruses at an MOI of 0.1. Viral RNA copy numbers in the culture supernatants were quantified at 6, 24, 48 and 72 h p.i. b Cells were infected with viruses at an MOI of 0.1 (left bar graph) or 1.0 (right bar graph) in the absence (NT) or presence of either nafamostat (Naf) or EST or both (Naf & EST). At 24 h p.i., viral RNAs in cells were detected by real-time RT-PCR. The x-axis shows the Cp values as an indicator of the viral RNA level. a, b Error bars indicate the standard deviations of triplicate wells. Mean values ± SD are shown. b Statistical significance was determined with two-way ANOVA. Multiple comparisons among different groups were adjusted with Tukey’s multiple comparison tests, in WK521 ****P < 0.0001 (NT vs Naf), ****P < 0.0001 (NT vs EST) and ****P < 0.0001 (NT vs Naf&EST); in Alpha ****P < 0.0001 (NT vs Naf) and ****P < 0.0001 (NT vs Naf&EST); in Beta ****P < 0.0001 (NT vs Naf) and ****P < 0.0001 (NT vs Naf&EST); in Gamma ****P < 0.0001 (NT vs Naf) and ****P < 0.0001 (NT vs Naf&EST); in Delta ***P = 0.0002 (NT vs Naf) and ****P < 0.0001 (NT vs Naf&EST); in Kappa ****P < 0.0001 (NT vs Naf) and ****P < 0.0001 (NT vs Naf&EST); in Omicron ****P < 0.0001 (NT vs EST) and ****P < 0.0001 (NT vs Naf&EST). Wuhan-type strain (WK521), Alpha (QHN001), Beta (TY8-612), Gamma (TY5-501), Delta (TY11-927), Kappa (TY11-330) and Omicron (TY38-873) variants were used.