title: Immunogenic and protective effects of an oral DNA vaccine against infectious pancreatic necrosis virus in fish.
abstract: DNA vaccines and oral DNA-based immunotherapy against infectious pancreatic necrosis virus (IPNV) have scarcely been studied in salmonid fish. Here, a vector with the capsid VP2 gene inserted was encapsulated in alginate microspheres to avoid the aggressive gastrointestinal conditions experienced following oral administration. Alginate microspheres were effective to protect the pDNA encoding VP2, which was expressed early in different organs of the vaccinated trout and that persisted for at least 60 days. The vaccine induces innate immune responses, raising the expression of IFN more than 10-fold relative to the fish vaccinated with the empty plasmid, at 7 and 15 days post-vaccination. Likewise, maximal expression of the IFN-induced antiviral Mx protein was recorded 15 days post-vaccination and neutralizing antibodies were also detected after 15 days, although their titre rose further at 21 days post-vaccination. Protection was high in the immunized fish, which showed around an 80% relative survival when challenged 15 and 30 days after vaccine delivery. Very low viral load with respect to the control group was detected in the vaccinated fish that survived 45 days after challenge. Thus, this study demonstrates the potential of the encapsulation technique for IPNV-DNA vaccine delivery and the relevance of the IPNV-VP2 gene for future plasmid constructs.
authors.affiliation: Centro de Investigaciones Biológicas, Departamento de Microbiología Molecular y Biología de las Infecciones, C/Ramiro de Maeztu 9, 28040 Madrid, Spain.
authors.forename: Ana I
authors.initials: AI
authors.lastname: de las Heras
authors.forename: S
authors.initials: S
authors.lastname: Rodríguez Saint-Jean
authors.forename: Sara I
authors.initials: SI
authors.lastname: Pérez-Prieto
mesh_terms: D000284:Administration, Oral; D000464:Alginates / Q000737:chemistry; D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D018175:Birnaviridae Infections / Q000401:mortality / Q000517:prevention & control / Q000662:veterinary*; D005393:Fish Diseases / Q000401:mortality / Q000517:prevention & control* / Q000821:virology; D019204:GTP-Binding Proteins / Q000276:immunology; D020869:Gene Expression Profiling; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D018061:Infectious pancreatic necrosis virus / Q000502:physiology*; D007372:Interferons / Q000276:immunology; D008863:Microspheres; D064547:Myxovirus Resistance Proteins; D017686:Oncorhynchus mykiss; D016133:Polymerase Chain Reaction; D016019:Survival Analysis; D014337:Trout; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology; D015678:Viral Structural Proteins / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D000464:Alginates; D057134:Antibodies, Neutralizing; D006603:Hexuronic Acids; D064547:Myxovirus Resistance Proteins; C509831:VP2 protein, infectious pancreatic necrosis virus; D019444:Vaccines, DNA; D015678:Viral Structural Proteins; D014765:Viral Vaccines; D020723:Glucuronic Acid; D007372:Interferons; D019204:GTP-Binding Proteins