HK2 and infection: Here, we found that early infection of LLC-PK1 cells by PDCoV significantly increased the expression of HK2 and LA in the cells and attenuated p-TBK1, a key protein in the RLRs signalling pathway, and the activation of the RLRs signalling pathway was inhibited; whereas when the expression of HK2 was reduced, the inhibitory effect of viral infection on the activation of the RLRs signalling pathway was attenuated and the expression of p-IRF3 and p-p65 proteins was further increased and viral replication was simultaneously reduced.