Study Of Coxsackievirus A16-infected Rhesus Macaques Model And Immunologic Characteristics

Coxsackievirus A16 is one of the important pathogens causing a human hand foot and mouth disease(HFMD),which gradually a serious public health problem in the Asia-pacific areas.In recent year,CA16 remains the 2nd most cause of HFMD,and was focused by researchers.Because of its increasing numbers of clinical cases,to support the vaccine development and pathogenesis study,a suitable infection model establishment is one of the critical steps for CA16 research.In this study,we use CA16-infected rhesus monkey to explore the infection of pathological feature and evaluate.In this paper,we made a preliminary study on the technology of CA16 inactivated vaccine.The results provide further information for the analysis of the mechanism about the CA16 infection and vaccine.The content of this project have 3 parts,the first part of our research based on EV71 monkey model of neonatal rhesus macaques preliminary,we established an animal model of CA16 infection in different ages,including adult monkeys(4-5 years old)young monkeys(8-10 months)and neonatal(1-3months).We observed the typical vesic?lar lesions in the oral mucosa,foot and mouth,clinical manifestations,virus dynamic distribution and viral load in the major organ,especially in lymphoid organs and CNS viral load,and raised in the peripheral blood of a IL-6 and TNF-a,infected with CA16(104 5 CCID50/monkey)via the respiratory tract by nasal spray.This is similar to the symptoms in the establishment of the model of EV71.However,in this process,there is pathological change in lung,lymph node etc.of infected animals,and a number of eosinophilic cells were found in the pathological observation of vesic?lar lesions.In addition,according to the CA16 will appear repeatedly infection in the clinical observation,we carried out 2th and 3rd repeated infections in the following study.The aim of this study was to analyze the viral pathogens reaction of CA16 infection.After repeated infection,all of the above animals co?ld not induce the neutralizing antibody response,which suggested that in the case of repeated infection,can only be induced by CA16 antigen stim?lation of IFN-r and IL4 specific T cell memory response in animals.No typical symptoms of CA16 infection were observed in adult monkey.The second part of our work,we used the experimental CA16 inactivated vaccine in healthy monkeys in 0,28 days immunization.Results indicated that the inactivated vaccine could significantly induce animals to generate neutralizing antibody and IFN-y specific secretion cells.Although the experimental vaccine has good immunogenicity,there are not satisfactory result about protective and safety after antigen exposure.Challenged by CA16,the specific performance of the experimental animal 85%showed vesic?lar lesions,viremia and related clinical symptoms.Serum neutralizing antibodies(GMT)were low level in which the body induced neutralizing antibodies.These results allow us to better understand the immunogenicity and immunoprotective effect of CA16 vaccine.In the third part,we further observed that CA16 can directly infect mature DC cells in the process of proliferation,and stim?late the cells to produce IL6,IL5 and other cytokines.After co-culturing CA16-infected DC cells and T cells,immune response induced by the back-transfusion of CA16-infected cells was observed in donor neonatal rhesus monkeys.It can be observed that the typical vesic?lar lesions in mouth and hand.In addition to the use of III clinical trials of EV71,based on the detection of cytokines,chemokines and neutralizing antibodies in CA16 positive samples,we further analysis of the CA16 infection related immune response in human body.The advantages of non-human primate models are high genetic similarity with human,therefore,it can display the virus infection and development with more comprehensive.We hope that through the non-human primate animal models in order to understand the pathogenic mechanism of CA16.A series studies of this research have provided theoretical basis and immunoprotective effect of CA16 vaccine.