title: Protection of chicken against very virulent IBDV provided by in ovo priming with DNA vaccine and boosting with killed vaccine and the adjuvant effects of plasmid-encoded chicken interleukin-2 and interferon-gamma.
abstract: The aim of this study was to examine the efficacy of in ovo prime-boost vaccination against infectious bursal disease virus (IBDV) using a DNA vaccine to prime in ovo followed by a killed-vaccine boost post hatching. In addition, the adjuvant effects of plasmid-encoded chicken interleukin-2 and chicken interferon-gamma were tested in conjunction with the vaccine. A plasmid DNA vaccine (pcDNA-VP243) encoding the VP2, VP4, and VP3 proteins of the very virulent IBDV (vvIBDV) SH/92 strain was injected into the amniotic sac alone or in combination with a plasmid encoding chicken IL-2 (ChIL-2) or chicken IFN-gamma (ChIFN-gamma) at embryonation day 18, followed by an intramuscular injection of a commercial killed IBD vaccine at 1 week of age. The chickens were orally challenged with the vvIBDV SH/92 strain at 3 weeks of age and observed for 10 days. In ovo DNA immunization followed by a killedvaccine boost provided significantly better immunity than the other options. No mortality was observed in this group after a challenge with the vvIBDV. The prime-boost strategy was moderately effective against bursal damage, which was measured by the bursa weight/body weight ratio, the presence of IBDV RNA, and the bursal lesion score. In ovo DNA vaccination with no boost did not provide sufficient immunity, and the addition of ChIL-2 or ChIFN-gamma did not enhance protective immunity. In the ConA-induced lymphocyte proliferation assay of peripheral blood lymphocyte collected 10 days post-challenge, there was greater proliferation responses in the DNA vaccine plus boost and DNA vaccine with ChIL-2 plus boost groups compared to the other groups. These findings suggest that priming with DNA vaccine and boosting with killed vaccine is an effective strategy for protecting chickens against vvIBDV.
authors.affiliation: Laboratory of Veterinary Microbiology, School of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon, Korea.
authors.forename: Jeong Ho
authors.initials: JH
authors.lastname: Park
authors.forename: Haan Woo
authors.initials: HW
authors.lastname: Sung
authors.forename: Byung Il
authors.initials: BI
authors.lastname: Yoon
authors.forename: Hyuk Moo
authors.initials: HM
authors.lastname: Kwon
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D018175:Birnaviridae Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary* / Q000821:virology; D001835:Body Weight / Q000276:immunology; D002060:Bursa of Fabricius / Q000276:immunology; D002642:Chick Embryo; D002645:Chickens; D006651:Histocytochemistry / Q000662:veterinary; D007114:Immunization / Q000662:veterinary*; D007243:Infectious bursal disease virus / Q000235:genetics / Q000276:immunology*; D007371:Interferon-gamma / Q000494:pharmacology; D007376:Interleukin-2 / Q000494:pharmacology; D009929:Organ Size / Q000276:immunology; D011201:Poultry Diseases / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D011897:Random Allocation; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D013047:Specific Pathogen-Free Organisms; D019444:Vaccines, DNA / Q000008:administration & dosage* / Q000276:immunology; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage* / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000914:Antibodies, Viral; D007376:Interleukin-2; D012367:RNA, Viral; D019444:Vaccines, DNA; D015164:Vaccines, Inactivated; D014765:Viral Vaccines; D007371:Interferon-gamma