Based on ACE2 and TMPRSS2 expression, IFNβ-ACE2 robustly inhibited infection across a concentration range of 100 pM to 1 μM, whereas sACE2(18-611) alone inhibited infection only at the highest concentration tested (1 μM) (Figure 3E,F,J,K), and both IFN-β preparations alone lacked detectable antiviral activity (Figure 3G,H,L,M). Here, TMPRSS2 is linked to infection.