title: DNA-mediated vaccination against infectious bursal disease in chickens.
abstract: The objective of the present study was to investigate the feasibility of a DNA vaccine to protect chickens against infectious bursal disease virus (IBDV) infection. A plasmid DNA carrying VP2, VP4, and VP3 genes of the standard challenge (STC) strain of IBDV was constructed and designated as pCR3.1-VP243-STC. One-day-old chickens were intramuscularly injected with the plasmid pCR3.1-VP243-STC once (group D1), twice (group D2), or three times (group D3) at weekly intervals. Chickens at 3 weeks old were orally inoculated with IBDV strain STC and observed for 10 days after challenge. Immunization twice (group D2) or three times (group D3) with the plasmid pCR3.1-VP243-STC conferred protection for 50-100 or 80-100% of chickens, respectively, as evidenced by the absence of clinical signs, mortality, and bursal atrophy. Although chickens vaccinated once (group D1) with the plasmid pCR3.1-VP243-STC did not have clinical signs, they exhibited varying degree of bursal atrophy after challenge. Enzyme-linked immunosorbent assay (ELISA) antibody titers in chickens protected by the plasmid pCR3.1-VP243-STC were significantly lower (P<0.05) than those not protected 10 days after challenge. IBDV antigen was not detected in the bursae of chickens that were protected by receiving the plasmid pCR3.1-VP243-STC twice or three times. The results indicate that the constructed plasmid pCR3.1-VP243-STC as a DNA vaccine provided efficacious protection for chickens against IBDV infection.
authors.affiliation: Department of Veterinary Pathobiology, Purdue University, 1175 ADDL, West Lafayette, IN 47907-1175, USA.
authors.forename: H C
authors.initials: HC
authors.lastname: Chang
authors.forename: T L
authors.initials: TL
authors.lastname: Lin
authors.forename: C C
authors.initials: CC
authors.lastname: Wu
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D000956:Antigens, Viral / Q000032:analysis; D018175:Birnaviridae Infections / Q000517:prevention & control; D019556:COS Cells; D002645:Chickens; D007111:Immunity, Cellular; D007243:Infectious bursal disease virus / Q000276:immunology*; D010957:Plasmids; D014611:Vaccination; D019444:Vaccines, DNA / Q000276:immunology*; D014765:Viral Vaccines / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D019444:Vaccines, DNA; D014765:Viral Vaccines