Identification of the functional domain of the porcine epidemic diarrhoea virus receptor

Porcine aminopeptidase N (pAPN) is a functional receptor for porcine epidemic diarrhoea virus (PEDV). Although PEDV is known to use the pAPN as the major receptor for cell entry, the crucial domain of the pAPN that interacts with the PEDV is still unknown. In the present study, in order to determine the crucial domain of the pAPN, the extracellular domain of pAPN was divided into three subdomains named SPA, SPB and SPC, based on its secondary structure. Recombinant plasmid pcDNA3.1 expressing SPA, SPB and SPC was constructed and introduced into Madin-Darby canine kidney (MDCK) cells by transfection. Following the detection of PEDV infection in transfected MDCK cells after PEDV challenge, we clearly demonstrated that the SPC subdomain plays a key role in cell entry of PEDV and its expression permits PEDV growth in transfected MDCK cells, while virus propagation can be inhibited by anti-SPC serum, indicating that the SPC subdomain appears to be a crucial functional domain in contributing to efficient PEDV infection.