(B) ACE2 cell surface expression on Caco-2 and Calu-3 was determined by quantitative real-time PCR. Data information: Data show the mean values and error bars are the SEM. Statistical analysis was performed using ordinary one-way ANOVA with Tukey's multiple-comparison test. *P≤0.05, **P≤0.01 (n=5 Caco-2 donors measured in monoplo), *p=0.0460 (n=5 Calu-3 donors measured in monoplo) 