2.1  Virus, Cells, and Antibodies
The PDCoV CHN-HN-1601 strain (GenBank access no. MG832584) used in this study was isolated from the intestinal contents of a piglet with diarrhea using porcine kidney LLC-PK1 cells in 2017. The eighth passage of PDCoV with a titer of 108.45 50% tissue culture infectious dose (TCID50)/mL was used for virus inoculation. IPEC-J2 cells were generously provided by Prof. Yongchang Cao (School of Life Sciences, Sun Yat-Sen University, Guangzhou, China). The cells were cultivated in Dulbecco’s Modified Eagle Medium/Ham’s F-12 (DMEM/F12) (Gibco, Carlsbad, CA, USA) containing 10% fetal bovine serum (FBS; Gibco, Carlsbad, CA, USA), 5 μg/mL insulin, 5 μg/mL transferrin, 5 ng/mL selenium (Sigma-Aldrich, St. Louis, MO, USA), 100 U/mL penicillin and 0.1 mg/mL streptomycin (Solarbio Life Sciences, Beijing, China). Cells were cultured at 37 °C in a humidified CO2 incubator (Thermo Fisher Scientific, Waltham, MA, USA). The monoclonal antibody (mAb), 1A3, raised against the PDCoV nucleocapsid protein was prepared in our laboratory. Mouse anti-β-actin mAb, mouse anti-IFIT1 and rabbit anti-ANAPC7 polyclonal antibodies were bought from Abcam (Cambridge, MA, USA). Horseradish peroxidase (HRP)-conjugated goat antimouse/rabbit immunoglobulin G (IgG) were obtained from Sigma-Aldrich. Alexa Fluor 488-conjugated goat antimouse IgG was the product of Thermo Fisher Scientific.