Resistance of Field-Isolated Porcine Epidemic Diarrhea Virus to Interferon and Neutralizing Antibody

SIMPLE SUMMARY: Porcine epidemic diarrhea (PED) is a porcine enteric viral disease that is characterized by watery diarrhea, vomiting, and dehydration. PED is highly contagious and causes significant mortality, especially in suckling piglets. The G2b variant PEDV, which started to become prevalent in China in 2013, has higher pathogenicity and transmissibility than existing viruses and causes economic losses in many countries, including South Korea. The present study shows that the G2b variant PEDV has a relatively high resistance to interferons and neutralizing antibodies. The present study has important implications for understanding the occurrence of variant PEDV and its pathogenesis. ABSTRACT: Variant porcine epidemic diarrhea virus (PEDV), belonging to the genogroup G2b, has higher pathogenicity and mortality than classical PEDV, belonging to the genogroup G1a. To understand the pathogenesis of the G2b PEDV, we examined the resistance of the G2b PEDV to interferon (IFN) and neutralizing antibodies, which are important for controlling PEDV infection. We found that the G2b PEDV showed higher resistance to IFN than G1a PEDV. The G1a PEDV could replicate in IFN-deficient Vero cells, but not in IFN-releasing porcine alveolar macrophages, whereas the G2b PEDV showed similar infectivity in both types of cells. We also found that G2b PEDV was not effectively blocked by neutralizing antibodies, unlike G1a PEDV, suggesting differences in the antigenicity of the two strains. These results provide an understanding of the occurrence of variant PEDV and its pathogenesis.