SARS-CoV replication was reduced significantly, but much weaker compared to the inhibition of MERS-CoV replication when the cells were treated with T-ex5 for 24 h before infection (Figure 4E), consistent with the comparatively low efficiency of SARS-CoV S cleavage by TMPRSS2 observed in the FRET and transient co-expression assays (Figure 2B,C). The gene discussed is TMPRSS2; the disease is infection.