title: Chimaeric VP2 proteins from infectious bursal disease virus containing the N-terminal M2e of H9 subtype avian influenza virus induce neutralizing antibody responses to both viruses.
abstract: Subunit vaccines capable of inducing antibody against both infectious bursal disease virus (IBDV) and H9 subtype avian influenza virus (AIV) were developed. The VP2 protein of IBDV was used as a cargo protein to display a 12-amino-acid immunodominant epitope derived from the N-terminal M2 extracellular domain (nM2e) of the H9 subtype AIV. Two chimaeric proteins were constructed by insertion of one copy of the nM2e into the PBC region (VP2BCnM2e(H9)) or by fusing four copies of nM2e to the carboxyl terminal (VP2-4nM2e(H9)) of VP2. Genes that encoded the VP2 chimaeras were subsequently cloned into a baculovirus vector and expressed in Spodoptera frugiperda cells. The recombinant proteins were used to vaccinate chickens at day 0 and again after 4 weeks. Blood was collected at 2-week intervals after primary and secondary vaccination to detect the antibody titre against VP2 or the nM2e via indirect enzyme-linked immunosorbent assay. Virus neutralization tests were also performed to measure anti-IBDV or anti-H9 AIV neutralizing antibodies in chick embryo fibroblasts. Oropharyngeal and cloacal swabs were collected 3, 5 and 7 days post H9 subtype AIV infection for virus isolation. Vaccination with VP2-4nM2e(H9) induced higher levels of antibody responses against IBDV or H9 subtype AIV, and provided better protection against an IBDV virulent challenge compared with vaccination with VP2BCnM2e(H9) vaccine, the wild-type VP2 subunit vaccine or the IBDV subunit commercial vaccines. Both chimaeric VP2 vaccines showed poor efficacy in inhibiting H9 virus replication post challenge. In summary, chimaeric proteins that contain the nM2e epitope were able to induce both IBDV and H9 subtype AIV-neutralizing antibody responses.
authors.affiliation: National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China.
authors.forename: Yinghua
authors.initials: Y
authors.lastname: Tang
authors.forename: Yuzhen
authors.initials: Y
authors.lastname: Gong
authors.forename: Yongwei
authors.initials: Y
authors.lastname: Wang
authors.forename: Peipei
authors.initials: P
authors.lastname: Wu
authors.forename: Yamei
authors.initials: Y
authors.lastname: Liu
authors.forename: Jihu
authors.initials: J
authors.lastname: Lu
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.forename: Fengxiang
authors.initials: F
authors.lastname: Hou
authors.forename: Jibo
authors.initials: J
authors.lastname: Hou
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D018175:Birnaviridae Infections / Q000517:prevention & control / Q000662:veterinary*; D002460:Cell Line; D002645:Chickens; D017931:DNA Primers; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D000939:Epitopes / Q000235:genetics; D005822:Genetic Vectors / Q000235:genetics; D007243:Infectious bursal disease virus / Q000235:genetics*; D053127:Influenza A Virus, H9N2 Subtype / Q000235:genetics*; D009500:Neutralization Tests / Q000662:veterinary; D011201:Poultry Diseases / Q000517:prevention & control* / Q000821:virology*; D011993:Recombinant Fusion Proteins / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D018411:Spodoptera; D015678:Viral Structural Proteins / Q000235:genetics*
chemical_list: D000914:Antibodies, Viral; D017931:DNA Primers; D000939:Epitopes; D011993:Recombinant Fusion Proteins; C082513:VP2 protein, infectious bursal disease virus; D015678:Viral Structural Proteins