2.1 Cell and Animal tissue samples
Animal tissue samples were provided by Zhengzhou zoo; CrandellRees feline kidney cell (CRFK) cells were purchased from Procell Life Science&Technology Co,.Ltd. In this study, CRFK were cultured in Dulbecco’s modified Eagle’s medium (Gibco, USA) that had been supplemented with 10% fetal bovine serum (HyClone, USA) and penicillin streptomycin (Life Technologies, USA). The CRFK were cultured to approximately 80% confluence and then infected with FPV HNZZ-2.