title: Efficacy of DNA vaccination by different routes of immunisation in sheep.
abstract: DNA vaccination, delivered through various routes, has been used extensively in laboratory animals. Few studies have focused on veterinary species and while results obtained in laboratory animals can often be extrapolated to veterinary species this is not always the case. In this study we have compared the effect of the route of immunisation with DNA on the induction of immune responses and protection of sheep to challenge with live Corynebacterium pseudotuberculosis. Intramuscular injection of plasmid DNA encoding an inactivated form of the phospholipase D (PLD) antigen linked to CTLA4-Ig resulted in the induction of a strong memory response and sterile immunity following challenge in 45% of the animals. In contrast, gene gun delivery or subcutaneous (SC) injection of the DNA vaccine induced comparatively poor responses and insignificant levels of protection. Thus, DNA vaccine efficacy in sheep is strongly influenced by the route of vaccination. Amongst intramuscular vaccinates, protected sheep had significantly elevated IgG2 responses compared to unprotected animals, while both subgroups had equivalent IgG1 levels. This suggests that the presence of IgG2 antibodies and hence a Th1-like response, induced by the DNA vaccine gave rise to protective immunity against C. pseudotuberculosis.
authors.affiliation: The Cooperative Research Centre for Vaccine Technology, CSIRO Livestock Industries, Private Bag No 24, Vic 3220, Geelong, Australia. r.derose@unimelb.edu.au
authors.forename: Robert
authors.initials: R
authors.lastname: De Rose
authors.forename: Jan
authors.initials: J
authors.lastname: Tennent
authors.forename: Peter
authors.initials: P
authors.lastname: McWaters
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Chaplin
authors.forename: Paul R
authors.initials: PR
authors.lastname: Wood
authors.forename: Wayne
authors.initials: W
authors.lastname: Kimpton
authors.forename: Ross
authors.initials: R
authors.lastname: Cahill
authors.forename: Jean Pierre Y
authors.initials: JP
authors.lastname: Scheerlinck
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology; D019470:Biolistics; D003354:Corynebacterium Infections / Q000276:immunology* / Q000517:prevention & control*; D016925:Corynebacterium pseudotuberculosis / Q000276:immunology; D007156:Immunologic Memory; D007273:Injections, Intramuscular; D007279:Injections, Subcutaneous; D012757:Sheep Diseases / Q000276:immunology / Q000517:prevention & control*; D034561:Sheep, Domestic / Q000276:immunology*; D014611:Vaccination / Q000662:veterinary*; D019444:Vaccines, DNA / Q000008:administration & dosage* / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D019444:Vaccines, DNA