FIG 7.

Endosomal protease(s) are required for CCoV-HuPn-2018 spike-mediated infection. (A to F) Huh7 cells (A, C, and E) or fAPN transiently transfected 293T cells (B, D, and F) were infected with CCoV-HuPn-2018pp in the absence (mock) or presence of the indicated concentrations of NH₄Cl (A and B), E-64d (C and D), or different cathepsin inhibitors (E and F). Luciferase activities were determined 24 h post-infection. Pseudotype entry is the ratio of the luciferase activity in cells treated with inhibitors over that in mock-treated cells. Error bars reveal the standard deviation of the means from three biological repeats. **, P < 0.001 compared to the level of mock-treated cells.