FIG 4.

Effect of furin inhibitor on MERS-CoV and SARS-CoV entry into LoVo cells. (A) Effect of inhibitors on MERS-CoV entry. LoVo cells were pretreated for 30 min with the furin inhibitor dec-RVKR-CMK (concentration, 0 to 100 μM). E64d (10 μM), camostat (10 μM), or a combination of both was used as a comparison control. The cells were then infected with 10⁵ PFU of MERS-CoV (MOI = 1) in the presence of inhibitor. The amount of viral mRNA in LoVo cells at 6 h postinfection was measured by real-time PCR (n = 4). (B) Effects of inhibitors on SARS-CoV entry. SARS-CoV was used instead of MERS-CoV; all experiments were carried out as described for panel A. A two-tailed Student t test was used to analyze statistical significance.