terials and Methods

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