The Epidemiological Investigation And Pathogenicity Research Of Avian Leukosis Virus Subgroup J In Layer Flocks

Subgroup J Avian Leukosis Virus was first found in broiler by a British scientist Payne in1988, mainlycaused infectious neoplastic diseases characterized by medulloblastoma and other cell malignancy. In ourcountry, we first found this virus in broiler in1999, in laying hens in2004, later in the local varieties ofchickens. since ALV-J was discovered,the host range continues to expand,the incidence of day-oldchickens infected gradually advance, mortality rates continue to rise, the induced tumor type is more andmore, recombination events have also occurred. In order to understand the prevalence and pathogeniccharacteristics of region ALV-J in layer flocks in Shandong Province, we conduct the ALV-J serological andmolecular epidemiological investigation and observed the tumorigenicity of virus in the natural infectedhens vivo within the scope of the parent generation egg breeder farms in Shandong Province, preliminaryresults obtained are as follows:From Shandong Province we select twenty four parent generation egg breeder farms and two goodsgeneration egg breeder farms, collecting eighty one live specimens and two thousand five hundred serum.Detecting serum antibodies by ELISA find that average positive rate of ALV-J antibody in layer flocksabout7.2%,the highest positive rate up to59.7%and the lowest positive rate is0.5%in single flocks.Taking live specimens organization, grinding, aseptic processing, then transfer to DF-1cells,maintaining seven days, detect the P27antigen in the cell supernatant using ELISA method, results showedthat12of81live specimens are ALV antigen-positive, then use PCR specific detection and cloning andsequencing to identify,10of these12ALV strains are ALV-J strain, two strains are ALV-J, ALV-C andALV-E of multiple recombinant strains, but these two strains are isolated from two different locations,different varieties of chickens.Through the gene sequence homology and phylogenetic analysis of10strains ALV-J’s gp85, gp37, rTM,DR1, E element, U3, R, U5gene sequence, the results show: the homology of gp85gene encoding aminoacid sequence is between87%-99%,of which six ALV-J strains are the closest relative of AmericanStandard strain ADOL-7501,four ALV-J strains are the closest relative of Britain prototype strainHPRS-103;Most of rTM and E element in3’UTR of ten ALV-J strains are missing, DR1relativelyconservative, U3, R, U5area in3’LTR relatively conservative. So isolated10ALV-J strains are from theU.S. standard strain ADOL-7501strain and Britain prototype strain HPRS-103.Isolated two rare multiple recombinant strains about ALV-J, ALV-C and ALV-E, after analyse sequencehomology and evolution on GP85, GP373’LTR gene, we found that: recombinant strains gp85gene fromALV-C gp37from ALV-E,3’UTR and3’LTR from ALV-J, and two strains have high homology, but theyfrom two different locations and different varieties of chickens isolated group, we concluded that therecombinant strains have a certain popular and dissemination. Through by histopathological observation study, we isolate12strains about ALV-J from naturalinfection of laying hens with their pathogenicity and induced tumor, the results show: ALV-J strains caninduced many type tumor:medullary cell tumors, hemangioma, fibrosarcoma, cholangiocarcinoma, We canfind a variety of rumor types in the same chickens, so that, ALV-J has pluripotent tumorigenic in layingflocks.We use FQ-PCR to detect the ALV-J loading, the of chNHE1protein, proto-oncogene c-myc,cancersuppressor gene P53and the content of endogenous virus EAV-0, E51in ALV-J naturally infected chickens,further analyse the relationship among the pathogenicity and the of tumorigenicity of ALV-J, the ALV-Jload, the expression quantity of chNHE1protein, proto-oncogene c-myc,cancer suppressor gene P53andthe content of endogenous virus EAV-0, E51. The results show that: In ALV-J naturally infected hens vivo,ALV-J load is three times-80times to SPF chicken, chNHE1protein, c-myc, p53, EAV-0, E51have largenumber of expression, rising with the increased of ALV-J load, in addition, chNHE1protein expression isrelatively high in the tumor tissue. It’s diversified the ALV-J induced tumors in laying hens and localvarieties of chickens, but the correlation with the level of their load of ALV-J and its induced tumorspectrum is not bovious; there was a positive correlation between the level of their load of ALV-J andamount of chNHE1expression, chNHE1protein is receptor for ALV-J infected cell; When ALV-J inducedtumor in tissue formation, the organization’s chNHE1expression level is relatively high, this showthat:chNHE1not only ALV-J infected cell teceptor, but also play a role in the process of tumor formation.ALV-J infection the body is able to activate the organism c-myc expression of p53gene and endogenousvirus EAV-0, E51.This study combines serology, molecular epidemiology and host factors comprehensive and systematicsurvey of the prevalence of ALV-J in layer flocks. ALV-J has pluripotent tumorigenic in layer flocks. ALV-Jinfection induced chNHE1receptor upregulation, closely related to tumorigenicity, c-myc and p53gene,endogenous virus expression is closely related to tumorigenicity.The results of this study have an in-depthunderstanding of the prevalence and pathogenicity of ALV-J, to provide a scientific basis for in-depth studyof the pathogenesis.