Study On Immune Effect Of Dendritic Cells Activated By Porcine Hemagglutination Encephalomyelitis Virus

Porcine hemagglutinating encephalomyelitis virus (PHEV) belonging to betacoronavirus is asingle-strand RNA viruses. PHEV can infect about1~3week-old piglets, causing acute contagiousdisease that characterized as vomiting, exhaustion or apparent neurological symptoms. Themortality rate of piglets infected by PHEV ranges from20%to100%. PHEV infection aredifficultly to detect clinically. In reality, adult pigs has good resistance to PHEV infection, butonce infected by PHEV，the pigs may appear wasting and stunting, and easily to mixed infectionwith other pathogens. As PHEV infection has spread around the world, where the infection rate inJilin, Liaoning province and Shandong province are about50%. Studies have shown that PHEVwill spread through the nervous system with acute clinical symptoms after administration of mice,and the mortality rate will reached100%without immune response. Now we don’t know whetherimmune cells in body were activated after PHEV infection. Dendritic cells (DC) is well knownmost efficiently antigen-presenting cells (APCs) to deal with antigen. When viral infection hasbeen detected by DC, cells secret type I interferons and proinflammatory cytokines which inducethe immune response to clear and kill virus-infected cells. But whether PHEV activated DC andwhether mice administrated by those DC are protected from on the body.For this purposes, DC precursor were isolated from Balb\c mouse bone marrow cells in vitroand the purity of DC was about80%after culture for8days with conditional medium. The resultsshowed that TNF-α, IL-1β, IL-10and IL-12secreted by DC was up-regulated; the gene expressionof NF κB pathway and inflammasome pathway and those cytokine above quantified by qPCRwere upregulated, but IFN-α, IFN-β and TLR7were suppressed obviously. The result showed thatDC can be effectively activated by PHEV, and have ability to activate lymphocyte effects toprotect body from pathogens.Whether matured DC activated by PHEV can protect mouse from PHEV infection? Weadministrated mice with DC loaded PHEV. Then level of proinflammation such as TNF-α、IFN-γand IL-6in serum and T cells response were detected. The result showed that cytokines thatreflected the level of T response were up-regulate and PHEV antibody have been in blood serum.Compared with controls, CD4/CD8of PHEV group was about1fold and the number of T cellssecreted IFN-γ raised to1.5fold. Lastly, those mouse were challenged by PHEV. The resultshowed that cytokines that reflected the level of T response were up-regulate and PHEV antibodyhave been in blood serum. After DC administration again，the mortality rate of those mice werelower. This showed that DC vaccine can provide better immune protection from PHEV.We conclude that DC can be activated and matured after PHEV stimulated. Their surface protein, cytokine secretion were up-regulate. And NF κB pathway and inflammasome pathway ofDC were activated; DC vaccine loaded with PHEV promote adaptive immune response in micethat were protective from invasion of PHEV.