KRT8 and infection: To evaluate the replication efficiency of foot-and-mouth disease virus (FMDV) in wild-type BHK-21 cells (WT-BHK-21) and Cbr3 gene knockout BHK-21 cells (BHK-21-ko-Cbr3), the cells were infected with a multiplicity of infection (MOI) of 0.1 for 16 h.