Cloning, Expression Of VP2 Infectious BursaL Disease Virus FX Strain And The Study Of Its Immunogenicity

VP2 gene from Infectious bursal disease virus FX strain was amplified RT-PCR, which was further sequenced and homology analysis.The results indicated that VP2 gene contains 1536 bp and encoding 512 amino acids.Compare with IBDV strains in GenBank,the homology of VP2 was 54.4%-99.3%in nucleotide and 46.1%-98.4%in amino acids.The phylogenetic analysis demonstrated that VP2 gene of IBDV FX strain is the closest with the Gt strain in homology,antigen epitopes of IBDV FX strain was analyzed with DNA star software,and the result showed that IBDV FX strain have the different antigenic epitopes with B87(JL)strain and B87 VP2(NJ)vaccine strain,and this indicate that FX strain have different with VP2 vaccine strain in protein antigen properties.The VP2 gene of IBDV FX was cloned into prokaryotic vector pGEX-6P-1 and expressed,and the recombinant plasmids(pGEX-6P-1-VP2)were extracted.The recombinant plasmids were transferred into E.coli BL21(DE3),and induced by IPTG,the result showed that receptor bacterium BL21(DE3)expressed geneVP2.The results of SDS-PAGE and Western blot indicated that the molecular weight of VP2 protein was about 40 KDa,and it had strong immunological activity.The recombination protein was purified by resin chromatographic columns of GST labeled,and the expression level was 1.168mg/mLChickens were inoculated intramuscularly with pGEX-6P-1-VP2 recombinant proteins,complete adjuvant and normal saline respectively.These chickens were injected with 100μL/chicken IBDV FX strain.The results showed that the recombination protein pGEX-6P-1-VP2 group had the highest protection rate which was 40%,and the adjuvant inoculated groups also had a low extent protection rate which was 10%,and the control group all died.The study showed that the recombination protein pGEX-6P-1-VP2 had a certain immune activity.