Aminopeptidase N Knockout Pigs Are Not Resistant to Porcine Epidemic Diarrhea Virus Infection

Porcine epidemic diarrhea virus (PEDV) is the etiologic agent of porcine epidemic diarrhea (PED), which is an acute, highly contagious, and devastating enteric viral disease in pigs. Surface expression of Aminopeptidase N (APN) is considered a functional receptor for infection by porcine epidemic diarrhea virus (PEDV). To test the role of APN in PEDV infection, we created APN knockout (KO) pigs by introducing frame shift mutations in the exon 2 or exon 3 of APN gene using CRIPSR/Cas9-mediated gene editing and somatic cell nuclear transfer. The resulting cloned pigs harbored homozygous or biallelic insertion/deletion in the target site of APN, and had no APN expression in the small intestines. After PEDV infection, both APN KO and wild type controls became infected and showed no differences in clinical signs, fecal viral shedding or antibody response. The results demonstrate that the expression of the APN gene is not necessary for infection of pigs with PEDV and that the absence of APN does not contribute to the resistance to the disease. This work indicates that an alternative receptor is needed to be identified for PEDV infection of pigs.