The Isolation Of ALV-J And REV And The Sequence And Pathogenicity Analysis Of ALV-J Isolated From Layers

Avian Leukosis and reticuloenendotheliosis are both disase can cause avian immunosuppressive . Subgroup J of ALV (Subgroup J of avian leukosis virus, ALV-J) was isolated and idenficated firstly by Payne LN from the meat-type chickens in late 1980s. And the subgroup J (Avian leukosis virus, ALV) is a new Subgroup of ALV , mostly cause myelocytomatosis(ML). Reticuloenendotheliosis virus (REV)can induce the avian Reticuloenendo- theliosis,generally ,avians infected by REV naturally will not cause acute symptom, but in some cases it will also lead to cell transformation (of the tumor cells) or cell pathological changes. Until now,the China's flocks were infected by these 2 virus seriously,and there are no reliable vaccine .In this study ,Avian leukosis viruses of subgroup J (ALV-J) were isolated from layers by inoculating the sample into chicken embryo fibroblast (CEF) cells and by indirect fluorescent assay (IFA) with ALV-J specific monoclonal antibody JE-9. Sequence comparisons indicated that their gp85 have identities were only in the ranges of 83.4%-87.3% compared with 5 international refe- rence strains and 86.4%-89.6% compared with 8 Chinese strains isolated from white meat-type chickens. The gp37 identities were in the range of 91.8-96.4% compared with the 5 international strains and 93.4-95.9% compar- ed with the 8 domestic strains. Otherwise, all the 8 domestic strains isolated from white meat-type chickens and the US strain 4817 have a nearly same 127 bp deletion mutation in the "E" region of 3 'Ter .So,we suppossed that all the chinese ALV-J came from a closer prototype virus. But ,the strain SD07LK1 and SD07LK2 have no this deletion mutation in the "E" region.these 2 layer's isolates are more close to the prototype HPRS-103 and have less deletion in 3'-Ter compared with some strains isolated in U S in 1990s . Obviously, these 2 ALV-J isolated from layers have different evolutional origins compared with other Chinese virus isolated from white meat-type chickens.We have not certained how the chinese layer flocks infected by the ALV-J, throgh horizontal infection or the virus have already existed in the breeds imported form other country? But ,if the latter case, we must quarantine the progenitor breeds imported every year.Now, many methods have used to detect the REV and ALV-J ,however,the virus isolation and identification is still the most effective and reliable way. It not only can confirmed the existence of virus , but also can get some living virus material for further study.The virus isolation has uncompared significance on virus biological research .During 2006-2007, five ALV-J and three REV were isolated through cell culture and indirect immunofluorescence assay (IFA).Meanwhile, we has isolated the REV from the layers .On the one hand,this diagnosed the disease accurately .And on the other hand, it provided living virus materials for further study.It has a great significance to predict and control the diseases .