title: Comparison of vaccine efficacy for different antigen delivery systems for infectious pancreatic necrosis virus vaccines in Atlantic salmon (Salmo salar L.) in a cohabitation challenge model.
abstract: Two strains of IPNV made by reverse genetics on the Norwegian Sp strain NVI-015 (GenBank AY379740) backbone encoding the virulent (T(217)A(221)) and avirulent (P(217)T(221)) motifs were used to prepare inactivated whole virus (IWV), nanoparticle vaccines with whole virus, Escherichia coli subunit encoding truncated VP2-TA and VP2-PT, VP2-TA and VP2-PT fusion antigens with putative translocating domains of Pseudomonas aeruginosa exotoxin, and plasmid DNA encoding segment A of the TA strain. Post challenge survival percentages (PCSP) showed that IWV vaccines conferred highest protection (PCSP=42-53) while nanoparticle, sub-unit recombinant and DNA vaccines fell short of the IWV vaccines in Atlantic salmon (Salmo salar L.) postsmolts challenged with the highly virulent Sp strain NVI-015 (TA strain) of IPNV after 560 degree days post vaccination. Antibody levels induced by these vaccines did not show antigenic differences between the virulent and avirulent motifs for vaccines made with the same antigen dose and delivery system after 8 weeks post vaccination. Our findings show that fish vaccinated with less potent vaccines comprising of nanoparticle, DNA and recombinant vaccines got infected much earlier and yielded to higher infection rates than fish vaccinated with IWV vaccines that were highly potent. Ability of the virulent (T(217)A(221)) and avirulent (P(217)T(221)) motifs to limit establishment of infection showed equal protection for vaccines made of the same antigen dose and delivery systems. Prevention of tissue damage linked to viral infection was eminent in the more potent vaccines than the less protective ones. Hence, there still remains the challenge of developing highly efficacious vaccines with the ability to eliminate the post challenge carrier state in IPNV vaccinology.
authors.affiliation: Norwegian School of Veterinary Science, Department of Basic Sciences and Aquatic Medicine, Section of Aquatic Medicine and Nutrition, P.O. Box 8146 Dep, N-0033 Oslo, Norway.
authors.forename: Hetron M
authors.initials: HM
authors.lastname: Munang'andu
authors.forename: Børge N
authors.initials: BN
authors.lastname: Fredriksen
authors.forename: Stephen
authors.initials: S
authors.lastname: Mutoloki
authors.forename: Bjørn
authors.initials: B
authors.lastname: Brudeseth
authors.forename: Tsun-Yung
authors.initials: TY
authors.lastname: Kuo
authors.forename: Inderjit S
authors.initials: IS
authors.lastname: Marjara
authors.forename: Roy A
authors.initials: RA
authors.lastname: Dalmo
authors.forename: Øystein
authors.initials: Ø
authors.lastname: Evensen
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001427:Bacterial Toxins / Q000235:genetics; D018175:Birnaviridae Infections / Q000517:prevention & control / Q000662:veterinary*; D004337:Drug Carriers / Q000008:administration & dosage; D004926:Escherichia coli / Q000235:genetics; D005393:Fish Diseases / Q000517:prevention & control* / Q000821:virology; D018061:Infectious pancreatic necrosis virus / Q000276:immunology*; D053758:Nanoparticles / Q000008:administration & dosage; D011550:Pseudomonas aeruginosa / Q000235:genetics; D020317:Salmo salar; D016019:Survival Analysis; D014611:Vaccination / Q000379:methods*; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D022223:Vaccines, Subunit / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D001427:Bacterial Toxins; D004337:Drug Carriers; D019444:Vaccines, DNA; D015164:Vaccines, Inactivated; D022223:Vaccines, Subunit; D014614:Vaccines, Synthetic; D014765:Viral Vaccines