No abstract

Porcine deltacoronavirus (PDCoV) and porcine epidemic diarrhea virus (PEDV) have often been detected simultaneously in piglets with coronavirus diarrhea. However, the intestinal immune response to the interaction between circulating PDCoV and PEDV is unknown. Therefore, this study was conducted to investigate the intestinal immunity of neonatal piglets that were exposed first to PDCoV and then to PEDV. The amounts and distribution of CD3 + T lymphocytes, B lymphocytes, and goblet cells (GCs) in the small intestine were analyzed by immunohistochemistry and periodic acid–Schiff staining, respectively. The expression levels of pattern recognition receptors and downstream mediator cytokines were analyzed by qPCR and ELISA. The results showed that the numbers of GCs, CD3 + T lymphocytes, and B lymphocytes in the duodenum and jejunum of the PDCoV + PEDV coinoculated piglets were increased compared with those of piglets inoculated with PEDV alone. The piglets in the PDCoV + PEDV group had significantly upregulated IFN-α and IFN-λ 1 compared with the PEDV single-inoculated piglets. These results suggest that PDCoV + PEDV-coinfected piglets can activate intestinal antiviral immunity more strongly than piglets infected with PEDV alone, which provides new insight into the pathogenesis mechanism of swine enteric coronavirus coinfection that may be used for vaccination in the future.

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.