Isolation and Identification of Porcine Epidemic Diarrhea Virus and Its Effect on Host Natural Immune Response

Abstract

Porcine epidemic diarrhea (PED) is a highly infectious intestinal disease caused by porcine epidemic diarrhea virus (PEDV). A PEDV strain was isolated from the piglet intestinal tract in Vero cells in Jiangsu Province, designated as the JS-A strain. PEDV was identified as the isolated virus by cytopathology, immunofluorescence assay, western blotting, transmission electron microscopy, and sequence analysis. The full-length genome of the JS-A isolate and the S gene were systematically analyzed, indicating that PEDV JS-A belongs to the G2a subtype, which is closely related to the prevalent PEDV in many countries and different from many current vaccines. Animal regression tests showed that piglets that are orally infected with the virus continue to develop diarrhea with yellowish and unpleasant odors. Further, piglets showed reduced food consumption and weight loss in the challenged group, while there were no abnormalities in the control group. In addition, Toll-like receptors (TLRs), RIG-I, and the downstream medium gene in the intestinal mucosa of newborn pigs infected with PEDV JS-A strain were studied. The neonatal Fc receptor (FcRn) was the only IgG transport receptor and protected IgG from degradation. Therefore, PEDV JS-A infection might inhibit FcRn expression by down-regulating TLRs and downstream signaling molecules. Taken together, isolation of the JS-A variant contributes to evolutionary analysis of the diarrhea virus. Further, the experimental infection model lays a foundation for further research related to vaccine development and the antiviral natural immune response of infected piglets, which helps us to better understand PEDV pathogenesis and immune mechanism.

Study on the effect of intestinal immunity that the neonatal piglet co-infection with porcine deltacoronavirus and porcine epidemic diarrhoea virus

“…In previous study, the pathogenicity of two virus have been analyzed, 5-day-old piglets were orally inoculated with 10 mL of 1×10 6 TCID 50 /mL PDCoV-CHN-HG-2017 or 3 mL of 1×10 5 TCID 50 /mL PEDV-JS-A, which were consistent with the results of this study [22,23]. Meanwhile, our previous reports showed that an animal model of PDCoV + PEDV coinfection was successfully constructed in neonatal noncolostrum-fed piglets, and demonstrated that coinfection of PDCoV and PEDV can alter PEDV tropism changes from epithelial cells of small intestine to gastric epithelial cells and macrophages in Peyer's patches in the ileum, and coinfection with PDCoV and PEDV are showed signi cant lower viral loads in the small intestine compared to a single infection with either virus [10].…”

Transmissible Gastroenteritis Virus Infection Up-Regulates FcRn Expression via Nucleocapsid Protein and Secretion of TGF-β in Porcine Intestinal Epithelial Cells

“…Our results suggest that TLR3, TLR9, and RIG-I may be used to activate the FcRn signaling pathway when TGEV infects IPEC-J2 cells. Recently, our research has shown that PEDV down-regulate the NF-κB signaling pathway to inhibit FcRn by TLR3 and RIG-I pathway in the early stage of infected piglets (Qian et al, 2019). PEDV and PDCoV N protein inhibited IFN-β by RIG-I pathway (Ding et al, 2014b;Likai et al, 2019), and we found that TGEV N protein up-regulated FcRn by RIG-I pathway.…”

A strain of porcine deltacoronavirus: Genomic characterization, pathogenicity and its full‐length cDNA infectious clone

“…Finally, we successfully isolated the PDCoV strain CHN-HN-1601 from the faeces of a diarrhoeic piglet. Interestingly, several other studies indicated that trypsin or pancreatin is also able to increase the rate of successful isolation of PDCoV or PEDV from clinical samples (Hofmann & Wyler, 1988;Hu et al, 2015;Qian et al, 2019). Hu et al (2015) demonstrated that PDCoV replicated well in LLC-PK1 cells with or without trypsin; however, no visible CPE was observed in the virus-infected cells without trypsin, and the virus titre was lower than that with trypsin.…”

“…Finally, we successfully isolated the PDCoV strain CHN‐HN‐1601 from the faeces of a diarrhoeic piglet. Interestingly, several other studies indicated that trypsin or pancreatin is also able to increase the rate of successful isolation of PDCoV or PEDV from clinical samples (Hofmann & Wyler, 1988; Hu et al., 2015; Qian et al., 2019). Hu et al.…”