Isolation Of A Novel IBDV Strain,Preparation Of VP2 Protein Monoclonal Antibody And Its Interaction With Bcl-2

Infectious bursal disease(IBD)is a highly infectious disease caused by infectious bursal disease virus(IBDV),mainly causing bursal atrophy in chicks.At present,IBD infection cases caused by the novel variant IBDV are rapidly spreading and showing an epidemic trend in China,which seriously affects the prevention and control of the disease.Therefore,it is of great importance to know the current epidemic situation of novel variant IBDV strains,and to study molecular characteristics and biological functions of the proteins,for IBD epidemic early warning and biosafety risk prevention and control.In order to provide reference for the epidemic dynamic monitoring of IBDV and explore the pathogenicity and pathogenesis of IBDV,the contents of this study are as follows.1.Isolation and identification of a novel variant strain of infectious bursal disease virusA novel variant of IBDV was isolated from chickens with IBD vaccine failure,named IBDV-LY21/2.The genetic evolution analysis of the main structural protein VP2 showed that IBDV-LY21/2 was in the same branch as the new variant strain,with 98.6% homology.IBDV-LY21/2 can adapt to chicken embryo and MC38 cells and cause atrophy and cell apoptosis of bursa of Fabricius after infecting chicks.2.Preparation and identification of monoclonal antibody against VP2 protein of infectious bursal disease virusMonoclonal antibody was prepared using a novel variant strain IBDV-LY21/2 VP2 protein as immunogen.The biological identification of the three monoclonal antibody cell lines 1G10F2,3E3E9 and 4D12G12 showed that 1G10F12 and 3E3E9 could be used to indentify VP2 protein by ELISA,Western blot and IFA,while 4D12G12 could be used in ELISA and IFA.3.Effects of interaction between VP2 protein and Bcl-2 protein on replication of infectious bursal disease virusGST-pull down and subcellular co-localization techniques were used to verify the relationship between the VP2 protein and Bcl-2.The results showed that there was an interaction between them.Overexpression of Bcl-2 protein could inhibit the replication of IBDV,while the inhibition of Bcl-2 protein promoted the replication of IBDV.In conclusion,this study successfully isolated a novel variant strain of IBDV that could cause bursa of Fabricius atrophy in chicks,providing data support for the prevention and control of IBDV.The three monoclonal antibodies could specifically recognize the specific epitopes of VP2 protein,which laid a foundation for the identification of IBDV and the study of its interaction with Bcl-2 protein.The interaction between VP2 protein and Bcl-2 affected the replication of IBDV,which laid a foundation for exploring the pathogenesis of IBDV.