Figure 4

Role of cathepsin proteases in HKU11, HKU13 and HKU17 pseudovirus entry into DF-1 cells. DF-1 cells were pretreated with the broad-spectrum cathepsin inhibitor E64D, CTSL-specific inhibitor (Z-FY-CHO), CTSB-specific inhibitor (CA-074), or DMSO (as a negative control) and then transduced with selected pseudovirions. In the same drug treatment, there are two adjacent bars of the same color; the bar on the left is treated with 5 μM, and the bar on the right is treated with 50 μM. Pseudoviral transduction was measured by luciferase activity at 48 h post-inoculation, with VSV-G pseudovirus used as a negative control; error bars indicate SEM (n ≥ 3).