The Preliminary Study Of Human Adenovirus’ Infectivity On The Cultured Primary Cells Derived From Tree Shrew

Human Adenovirus(HAd V)belongs to the Adenoviridae mammalian adenovirus genus(Mastadenovirus).It is a linear double-stranded DNA virus without an envelope.HAd V is a widely distributed infectious pathogen.Infection often induces acute upper and lower respiratory diseases and acute bronchiolitis,gastroenteritis,epidemic conjunctivitis,keratoconjunctivitis,meningoencephalitis,cystitis,myocarditis and even severe pneumonia disease.HAd V infection is usually self-limiting,but for children with low immunity and special populations,the infection may cause more serious consequences.At present,there are no specific drugs and vaccines for the treatment of HAd V infection.Since most HAd V infections are mild and self-limiting,the focus of clinical treatment of adenovirus infections is mostly to reduce the symptoms of patients.HAd V infection is species-specific and can only effectively infect and replicate in natural hosts.The research on HAd V mainly uses animals such as hamsters,humanized mice and pigs,and the virus type is mainly the HAd V5(group C).Although type C HAd V can be replicated in hamsters and humanized mice,the limited humanized genes and the immune system of experimental animals cannot simulate the human immune system’s response to human adenovirus infection.And the evolutionary relationship between hamsters and others,human functions and immune tolerance are quite different.Establishing a suitable animal model of HAd V is a key problem to be solved urgently.The whole genome sequencing,evolutionary analysis,physiological anatomy,neurodevelopment and immune response of tree shrews are closely related to human.Tree shrews have more advantages than rodents in developing potential experimental animals to simulate human beings.So,tree shrew has been widely used in the research of human virus infection.In this study,HAd V3 and HAd V7 virus strains were cultured by human pulmonary adenocarcinoma cell cells(A549).The primary lung epithelial cells of tree shrews were isolated by using collagenase and trypsin digestion,and after identification,in vitro infection experiments were conducted.The TSLEC、TSKEC and TSDF were infected with HAd V3 and HAd V7,the results showed that the primary lung epithelial cells of tree shrew infected hadv3 and hadv7 more easily than other primary cells(P < 0.001).Studies on the infection characteristics of the primary lung epithelium of tree shrews showed that the viral load continued to increase from 12 h to 96 h after infection,which was basically similar to the growth trend and viral load level of the positive control group.Through analysis of One-Way ANOVA,the viral load of HAd V3 and HAd V7 infected with TSLEC at 96 h and 120 h were not significantly different(P < 0.05).The detection of tree shrew anti-virus-related inflammatory factors found that the transcription levels of inflammatory factors showed a continuous upward trend,in which the transcription levels of IL-6 and IL-10 increased nearly a hundred times.In summary,TSLEC has the potential to become a cell model of hadv3 and hadv7 infection,which lays a foundation for further exploration of the establishment of HAd V tree shrew model.