TMPRSS4 and infection: At 72 h post infection (hpi), the different levels of rTS-2B/GFP titers from the cells expressing proteases were observed in the order of Tmprss9 > Cfd > Prss23 = Tmprss4 > F7 > ev (Fig. 3C), and those of rTS-GFP titers were observed in the order of Tmprss9 > Tmprss4 > F7 > ev = Cfd = Prss23 (Fig. 3D).