Characterization the immunogenicity of recombinant VP2 of infectious bursal disease virus containing N-terminal M2e of avian influenza virus
含禽流感病毒M2e氨基端抗原表位的重组传染性法氏囊病毒VP2蛋白的免疫原性鉴定

Objective]We developed subunit vaccines against H5 or H9 subtype avian influenza viruses(AIV) and infectious bursal disease viruses(IBDV).Viral protein 2(VP2) of IBDV was used as cargo protein to display a 12-amino-acid(aa) immunodominant epitope derived from N-terminal M2 extracelluar domain(nM2e) of H5 or H9 subtype AIV.Methods] The aa and nucleotide sequence of nM2e was determined by comparing the available avian influenza vaccine strains and alignment the AIV sequence available in GenBank.One copy of H5 or H9 nM2e was inserted into PBC region of VP2 origin from IBDV B87 vaccine strain by fusion polymerase chain reaction.The VP2BCnM2e recombinants were cloned into Bac-to-Bac expression system and transfected to Sf9 cell.The expressed chimeric protein was characterized by indirect immunofluorescence assay and Western blotting,and subsequently was used as antigen to develop vaccine.The non-immunized chicken was given two injections with the vaccine at a 4-week interval.Serum against VP2 and nM2e was tested by indirect ELISA and virus neutralization in chick embryo fibroblast.Results] Both VP2BCnM2e recombinants were successfully constructed and expressed in Sf9 cell.Both chimeric proteins elicited antibody against VP2 and nM2e.The antibody level elicited by VP2BCnM2eH5 vaccine was higher than that of VP2BCnM2eH9.Conclusion] Both chimeric proteins were immunigenic,and the efficacy of VP2BCnM2eH5 was higher than VP2BCnM2eH9 in chicken.