BEFV induces autophagy benefiting virus replication. A MDBK and BHK-21 cells were infected with BEFV at different MOIs for 18 h and the levels of LC3-II were determined. B MDBK cells were seeded in 6-well cell culture dishes with 2 × 105 cells. BEFV-infected MDBK cells at a MOI of 1 for 18 h were then treated with NH4Cl (20 mM) alone or NH4Cl (20 mM) combined with rapamycin (5 µM) or starvation (cells supplemented with no FBS), and the cell lysates were collected individually at 18 h post-infection (hpi) for immunoblotting with the respective antibodies. C Cells were pretreated with rapamycin (5 µM) and 3-MA (1.25, 2.5, 5, and 10 mM), respectively, for 30 min and then infected with BEFV at an MOI of 1 for 18 h. The effects of rapamycin and 3-MA on BEFV production were determined by analyzing the expression level of the BEFV M protein (upper panel) and virus titer (lower panel). All data shown represent the mean ± SD calculated from three independent experiments. Signals in all Western blots were quantified with Image J software. The levels of indicated proteins in the mock control (mock, DMSO or un-treatment) were considered onefold. The protein levels were normalised to those for β-actin. The activation and inactivation folds indicated below each lane were normalized against values for the mock control. The predicated size of each protein was labeled at the right-hand side in kDa.