The Immunopathogenesis And Tree Shrew Model Research Of Dengue Fever

Dengue virus(DENV)belongs to a subgroup serotype ofFlaviviruses,mainly disseminated through Aedes aegypti,Aedes albopictus and other insect vectors.Dengue has become the world's second most widespread disease which after malaria and is more than 100 cunntries about 2.5 billion people facing the risk of infection with dengue fever each year,which confirmed more than 50 million cases of dengue fever every year.With global warming,increasing economic and tfade exchanges,the global tropical and subtropical regions are facing increasing risk of dengue infection,resulting in a serious social burden.Antibody-dependent enhancement(ADE)has been thought to be involved in the immuno pathogenesis of severe dengue fever infection like dengue hemorrhagic fever(DHF)and dengue shock syndrome(DSS).More and more studies have shown that antibody-dependent infection does not only exist between heterotypic dengue virus,and also existed between flavivirus,JEV,DENV and other flaviviruses.The challenge and restricting of development dengue vaccines is not only due to the ADE among flaviviruses,but also lack of ideal animal model of denguehemorrhagic to restate the ideal of human dengue virus infection.Tree shrew,an animal whose genome has a significantly higher similarity with primates than rodents and has been used in many viral model studies.In this study,the phylogenetic and recombination analysis were studied by MEGA7.0,RDP4.0 and BioEdit software among ZIKA,JEV,WNV and DENV.The origin and epidemiological trend of the DENV-2 genome were analyzed for the more comprehensive understanding of DENV and its close relationship between the insect virus and the epidemic and evolutionary relationship.The autophagy microarray was used to detect the autophagy gene and pathway way of DENV ADE in THP-1 cells,and the effect of JEV E protein antibody on DENV infection THP-1 cells,microRNA profile were detected by in vitro ADE model on PBMCs cells.43 healthy adult tree shrews were infected throughintravenous and subcutaneous injection of dengue virus,observation of fever,blood,viremia,neutralizing antibody and histopathology,and virus detection in liver and brain.The results showed that the complete genomic structure of the flaviviruses(DENV,WNV,JEV and ZIKA)had a high degree of structural similarity,especially in DENV and WNV viruses.However,there are some differences between the genomic structure,the ZIKA virus has a unique propeptide between C and M in the structural protein region,and the 2K protein between NS4A and NS4B is not exist in the non-structural protein region of JEV.The vitro ADE model of DENV was successfully established on THP-1 cells.The serum samples of JEV IgG,DENV IgG and IgM were examined in 30 patients.They were both JEV IgG,DENV IgG and IgM positive(>2 times the negative).In the serum of patients with dengue fever,the JEV IgG value is similar to DENV IgM but differs from DENV IgG.To research the changes of miRNA expression patterns in the PBMCs during the direct infection of ADE and DENV-3,global cellular miRNA expression patterns following infection were compared with those of the controls.The results showed that,compared with the DENV-3-0 h group,there were 8 up-regulated and 7 down-regulated known miRNAs in the DENV-3-8 h group,as well as 13 up-regulated and 1 down-regulated known miRNAs and 1 up-regulated novel miRNA in the DENV-3-24 h group.Moreover,there were 10 up-regulated and 1 down-regulated known miRNAs in the ADE infection-8 h group,as well as 37 up-regulated and 4 down-regulated known miRNAs in the ADE infection-24 group relative to the ADE infection-0 h group.Dengue fever(DF)developed 2 to 33 days after infection in 4 of 32 animals.Blood chemistry of aspartate transaminase(AST),alanine aminotransferase(ALT)and alkaline phosphatase(ALP),which peaked at 12 days after infection.A modest thrombocytopenia and white blood cell with slight decrease,no significant changes were observed in RBC,HGB,HCT,MPV,MCV,MCH,MCHC,RDW-SD,RDW-CV and PDW but changes were observed in WBC,PLT,PCTand P-LCR..There were five deaths among 43.Viremia peaked at 2 to 7 days and neutralizing titerpeaked at 7 to 15 days after infection.Pathological studies on the tissues were also performed and the pathological changes occurring in liver and brain in some groups were examined.Dengue disease has become a major global public health concern,but an idealof dengue hemorrhagic animalmodel recapitulating human dengue virus infection is not yet available.It is a significant impediment in advancingof the early events involved in thepathogenesis of dengue disease.Find a suitable animal model is a major challenge and necessitates for vaccine research andbasic research of dengue virus.