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

Abstract

Porcine deltacoronavirus (PDCoV) and porcine epidemic diarrhoea virus (PEDV) have been often simultaneously detected in coronavirus diarrhea piglets. But the intestinal immune of the interaction between the co-circulating PDCoV and PEDV are unknown. Therefore, the study was conducted to investigate intestinal immunity of neonatal piglets that were exposed with PDCoV first and then PEDV subsequently. The amount and distribution of CD3+T lymphocytes, B lymphocytes and goblet cells (GCs) in small intestine were analyzed by immunohistochemistry and periodic acid-schiff respectively. The expression of pattern recognition receptors and downstream mediator genes were analyzed by qPCR. The results showed that the number of GCs, CD3+T lymphocytes and B lymphocytes in the small intestine of the PDCoV + PEDV co-inoculated piglets were increased compared with PEDV single-inoculated piglets. The piglets in the group of PDCoV + PEDV were significantly up-regulated IFN-α and IFN-λ1 when compared with the PEDV single-inoculated piglets. These results suggest that the PDCoV + PEDV co-infected piglets can superiorly activate intestinal antiviral immunity compared to PEDV single-infected piglets, which provide a new insight into the pathogenesis mechanism of swine enteric coronavirus coinfection that may be used for vaccination in the future.