Fig. 3.

Autophagy promotes PDCoV replication. (A) LLC-PK1 cells were pretreated with autophagy activator rapamycin (62.5 μg/mL) or autophagy inhibitor wortmannin (5 μg/mL) prior to PDCoV infection (MOI = 2). After PDCoV adsorption for 1 h, the cells were further cultured in fresh medium in the absence or presence of rapamycin (31.2 μg/mL) or wortmannin (2.5 μg/mL). The expressions of LC3-II and PDCoV N was analyzed by western blot at 24 hpi. Results were presented as the ratio of target protein band intensity to β-actin band intensity. (B) The virus titer (lgTCID₅₀/mL) in LLC-PK1 cell supernatants was calculated by the method of Reed and Muench. (C, D) Determination of cytotoxicity of rapamycin and wortmannin by CCK-8 assay. Values represent the mean ± SEM for three independent experiments. *P <  0.05; **P <  0.01; ***P <  0.001.