Effects of porcine deltacoronavirus on infection and secretion of immune factors in porcine dendritic cells
Porcine deltacoronavirus(PDCoV)is a new intestinal coronavirus that causes diarrhea in nursing piglets,which seriously harms the pig industry.This study aims to use porcine dendritic cells(pDCs)as a model to explore whether PDCoV can effectively infect pDCs and its effect on the secretion of anti-viral cytokines.Peripheral anticoagulant cells of porcine were first collected.Por-cine peripheral blood mononuclear cells were then isolated and induced by interleukin-4(IL-4)and colony-stimulating factor(GM-CSF)to obtain immature dendritic cells,and their biological mor-phology was observed by inverted microscopy and transmission electron microscopy.Western blot and laser confocal assays were used to detect whether the virus could infect pDCs,and qRT-PCR were used to detect the expression of antiviral factors IFN-α and ISG56.The results showed that pDCs with typical dendritic cell morphology were successfully isolated and cultured,and PDCoV could effectively infect and replicate in pDCs and produce infectious progeny viral particles,with a viral titer of 4.4 lgTCID50/0.1 mL.At the same time,the effect of PDCoV infection on the expres-sion of antiviral factors in pDCs was detected,and the results showed that high levels of IFN-α and ISG56 were produced 48 h after infection in pDCs.In summary,we successfully obtained pDCs by induced culture,and confirmed for the first time that PDCoV can infect pDCs in vitro and effec-tively replicate in cells,and pDCs promote the secretion of IFN-α and ISG56 after viral infection to exert antiviral immune effects,which provides a novel idea for subsequent research on the patho-genic mechanism of PDCoV.