FIG. 8.
Effect of endosomal cysteine protease inhibitors on RA59/MHV-2S (A) and RA59/MHV-2SS757R (B) replication in L2 cells. Cells were pretreated with 100 μM E-64 (to inactivate endosomal cysteine proteases) or 10 μM Z-FY-DMK (to specifically inactivate cathepsin B and L) for 3 h, and then infected with viruses in the presence of inhibitor for 1 h. Growth medium containing inhibitors was then removed from cells and replaced with fresh medium without inhibitors. At indicated times (10, 14, and 18 h), supernatants were harvested and viral yields were determined by plaque assay.