The replication of Beta, Delta and Omicron variants in Calu-3 was different from the other two cell lines starting from 3 hpi (Beta: p < 0.0001 vs. Vero E6 and p < 0.001 vs. Vero E6/TMPRSS2; Delta: p < 0.01 vs. Vero E6, p < 0.05 vs. Vero E6/TMPRSS2; Omicron: p < 0.0001 vs. Vero E6 and Vero E6/TMPRSS2), while results obtained from Vero E6 and Vero E6/TMPRSS2 cultures were different 24 hpi for all the three virus variants infections (p < 0.0001). This evidence concerns the gene TMPRSS2 and infection.