title: Characterization of two recombinant HVT-IBD vaccines by VP2 insert detection and cell-mediated immunity after vaccination of specific pathogen-free chickens.
abstract: Infectious bursal disease (IBD) is an avian viral disease that causes severe economic losses in the poultry industry worldwide. The live IBD virus (IBDV) has a potential immunosuppressive effect. Currently available IBDV vaccines have shortcomings, prompting the development of safer and more effective vaccination approaches, including the use of the recombinant turkey herpesvirus vaccine expressing the immunogenic structural VP2 protein of IBDV (recombinant HVT (rHVT)-IBD). The objectives of this study were twofold: (i) to develop in vitro assays and molecular tools to detect the VP2 protein and gene and (ii) to evaluate cell-mediated immunity (CMI) induced by rHVT-IBD vaccination of day-old specific pathogen-free chickens. The VP2 protein expressed by rHVT-IBD-infected chicken embryo fibroblasts was detected using the enzyme-linked immunosorbent assay and immunofluorescence. Using molecular techniques, the VP2 gene was detected in various organs, providing a method to monitor vaccine uptake. rHVT-IBD vaccination induced CMI responses in specific pathogen-free chickens at 5 weeks. CMI was detected by measuring chicken interferon-gamma after ex vivo antigenic stimulation of splenocytes. Moreover, our results showed that the enzyme-linked immunospot approach is more sensitive in detecting chicken interferon-gamma than enzyme-linked immunosorbent assay. The tools developed in this study may be useful in the characterization of new-generation recombinant vaccines and the cellular immune response they induce.
authors.affiliation: a Avian Virology & Immunology Unit , Veterinary and Agrochemical Research Centre , Brussels , Belgium.
authors.forename: Fiona
authors.initials: F
authors.lastname: Ingrao
authors.affiliation: a Avian Virology & Immunology Unit , Veterinary and Agrochemical Research Centre , Brussels , Belgium.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Rauw
authors.affiliation: a Avian Virology & Immunology Unit , Veterinary and Agrochemical Research Centre , Brussels , Belgium.
authors.forename: Thierry
authors.initials: T
authors.lastname: van den Berg
authors.affiliation: a Avian Virology & Immunology Unit , Veterinary and Agrochemical Research Centre , Brussels , Belgium.
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Lambrecht
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology*; D018175:Birnaviridae Infections / Q000517:prevention & control / Q000662:veterinary* / Q000821:virology; D002645:Chickens; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D026002:Herpesvirus 1, Meleagrid / Q000276:immunology*; D007111:Immunity, Cellular; D007243:Infectious bursal disease virus / Q000276:immunology*; D007371:Interferon-gamma / Q000276:immunology; D008297:Male; D011201:Poultry Diseases / Q000517:prevention & control* / Q000821:virology; D013047:Specific Pathogen-Free Organisms; D014611:Vaccination / Q000662:veterinary; D014614:Vaccines, Synthetic / Q000276:immunology; D015678:Viral Structural Proteins / Q000235:genetics / Q000276:immunology; D014765:Viral Vaccines / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; C082513:VP2 protein, infectious bursal disease virus; D014614:Vaccines, Synthetic; D015678:Viral Structural Proteins; D014765:Viral Vaccines; D007371:Interferon-gamma
keywords: Chicken; ELISPOT; cell-mediated immunity; infectious bursal disease; recombinant HVT