title: [Recombinant Vp2 protein of infectious bursal disease virus AH1 strain expressed in insect cells: a vaccine candidate].
abstract: Protective immune response of the available IBD vaccine is insufficient to fully protect against the prevailing strain of the infectious bursal disease virus (IBDV). Such a vaccination escape IBDV field isolate idenfied from Anhui province of China in December 2007, where IBD broke out at 2 weeks post vaccination. The IBDV vp2 gene was cloned into pFastBacHTA donor plasmid, followed by generation of the recombinant bacmid DNA pBac-VP2. The latter was used to transfect insect cell Sf9 with Lipofectamine to produce recombinant baculovirus vBac-VP2. The Sf9 cells infected with vBac-VP2 were stained positive against IBDV antibody using the indirect immunofluorescence assay (IFA), which was also confirmed by the detection of IBDV Vp2 protein in the infected Sf9 cells by IBDV sandwich ELISA. Western blotting revealed that the calculated protein of approximately 53 kDa was in the expressed in the insect cells. Moreover, virus-like particles (VLPs) and "inclusion body-like"structure in the infected Sf9 cells were observed under electron microscopy. We further developed an indirect ELISA for the detection of the IBDV antibodies, which was specific and sensitive. In addition, the lysates of vBac-VP2 infected cells was used to immunize 2-week-old SPF chickens, followed by challenging with the virulent IBDV, the survival rate was 30% at 14 days post primary immunization, however, the survival rate was 100% at 14 d after the booster vaccination. The ELISA antibody titers was up to 3.2 x 10(3) and neutralization antibody titer was 2536, significantly higher than those of one-shot vaccination, 8 x 10(2) and 1106, respectively. The immunized chickens did not show any clinical signs and histopathological changes of infection in 7-days trial time. The bursa/body-weight ratios were higher than those of the unimmunized control (P < 0.05). The virus-like-particle recombinant Vp2 protein expressed in insect cells promises to be a novel subunit vaccine and diagnostic reagent candidate for IBDV.
authors.affiliation: Key Laboratory of Animal Diseases and Immunology, Ministry of Agriculture National Center for Engineering Research of Veterinary Bio-products, Institute of Veterinary Medicine, Jiangsu Academy of Sciences, Nanjing 210014, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Ouyang
authors.forename: Yongshan
authors.initials: Y
authors.lastname: Wang
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhou
authors.forename: Haibin
authors.initials: H
authors.lastname: Zhang
authors.forename: Yude
authors.initials: Y
authors.lastname: Tang
mesh_terms: D000818:Animals; D016367:Baculoviridae / Q000235:genetics; D002460:Cell Line; D002645:Chickens; D007243:Infectious bursal disease virus / Q000276:immunology*; D007313:Insecta / Q000235:genetics / Q000378:metabolism*; D011201:Poultry Diseases / Q000517:prevention & control; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D015678:Viral Structural Proteins / Q000096:biosynthesis* / Q000235:genetics; D014765:Viral Vaccines / Q000276:immunology*
chemical_list: D011994:Recombinant Proteins; C082513:VP2 protein, infectious bursal disease virus; D015678:Viral Structural Proteins; D014765:Viral Vaccines