Figure 6.

Amiodarone antiviral effect is rescued by in vitro proteolysis of GP. (a) Amiodarone does not affect the cell content of cathepsins B and L. Vero cells treated for 12 h with 10 μM amiodarone were lysed and cathepsin activity was measured in the cell lysates. Data (mean ± SD) are presented as percentages of Cat B + Cat L measured in the absence of drug (no drug). (b) In vitro proteolysis of GP rescues viral infectivity. Vero cells, treated for 16 h with 10 μM amiodarone, were incubated for 2 h with GP-pseudotyped virus (MOI of 0.1 FFU/cell) treated for 1 h with either reaction buffer alone (mock pre-activated) or 0.2 mg ml^–1 thermolysin (pre-activated). Cells were then incubated for 24 h in plain medium (no drug) or with 10 μM amiodarone, GFP-positive cells were estimated by cytofluorimetry. Data (mean ± SD, N = 3 experiments in duplicate) are percentages of GFP-positive cells with respect to cells exposed to mock pre-activated virus in the absence of amiodarone, set as 100% (* = P < 0.05).