In ovo DNA immunisation followed by a recombinant fowlpox boost is fully protective to challenge with virulent IBDV

• Published in: Vaccine Vol. 24; no. 23; pp. 4951 - 4961
• Main Authors: Haygreen, E.A., Kaiser, P., Burgess, S.C., Davison, T.F.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 05.06.2006; Elsevier; Elsevier Limited
• Subjects: Amniotic Fluid - metabolism; Animals; Applied microbiology; Automation; Biological and medical sciences; Birnaviridae Infections - immunology; Birnaviridae Infections - prevention & control; Birnaviridae Infections - veterinary; Chick Embryo; Chickens; Deoxyribonucleases - metabolism; Deoxyribonucleic acid; DNA; DNA vaccine; DNA, Recombinant; Embryos; Fowlpox virus - immunology; Fundamental and applied biological sciences. Psychology; Genes; Genetic engineering; Genomes; IBDV; Immunization, Secondary; In ovo vaccination; Infectious bursal disease virus; Infectious bursal disease virus - immunology; Infectious bursal disease virus - pathogenicity; Microbiology; Mortality; Poultry; Poultry Diseases - immunology; Poultry Diseases - prevention & control; RNA, Viral - isolation & purification; Vaccines; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies (general aspects); Vaccines, DNA - administration & dosage; Vaccines, DNA - immunology; Viral Vaccines - administration & dosage; Viral Vaccines - immunology; Virulence; Europe; DNA vaccine; IBDV; In ovo vaccination; Immunization; Vaccination; Recombinant DNA; Genetic vaccine
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2006.03.060

The aim of this study was to investigate the potential use of DNA vaccination delivered in ovo for protecting against challenge with infectious bursal disease virus (IBDV). Using a plasmid expressing the β-galactosidase gene, DNA was successfully delivered to the embryo after in ovo injection and localises to the proventriculus and thymus. The coding sequence for the immunogenic IBDV protein, VP2, was cloned into pCI-neo, creating pCI-Vp2. Complete protection against IBDV was obtained by priming in ovo with pCI-Vp2, followed by boosting with the fowlpox recombinant, fpIBD1, also expressing the VP2 gene. This complete protection was not evident with either of the experimental vaccines on their own. An antibody response was not detected after the prime-boost vaccination, even after chicks had been challenged with IBDV, implying that the DNA prime delivered in ovo stimulated a protective cellular immune response.