SBIR-STTR Award

The goal of this Phase I project is to establish the feasibility and technical merit of a recombinant approach to ISAV vaccine development. APPROACH: Recent developments in recombinant vaccine technology prompted us to explore this approach to ISAV vaccine design. The ISAV HA and NP proteins elicit a humoral immune response in Atlantic salmon and are potential vaccine candidates. Since cytotoxic cells function in controlling viral infections in fish, T cell epitopes will be incorporated into the vaccine constructs to further improve the efficacy of the vaccine(s). We will be using a bacterial expression system that directs the recombinant fusion protein to inclusion bodies where greater than 50% of the cellular protein is the recombinant fusion protein. In addition, the system is versatile and can accept several antigens simultaneously; an important consideration when designing vaccines against viruses that display antigenic differences between isolates and for viruses that undergo antigenic drift and shift. NON-TECHNICAL SUMMARY: ISA virus, an unclassified Orthomyxoviridae is an emerging pathogen associated with disease in farmed Atlantic salmon. Losses incurred in Maine due to ISA alone in 2002 are estimated to be over $12 million (US). In response to the threat, salmon producers have stated that an ISAV vaccine is needed. The ultimate success of the project will be the construction of a safe, efficacious, recombinant ISA virus vaccine. Evaluation of vaccine efficacy will involve assessing the humoral immune response post-vaccination and post-challenge, measuring virus clearance post-challenge and determining the relative percent survival in vaccinated fish post-challenge. An efficacious ISAV vaccine would provide a disease management tool that in combination with good fish health practices would ensure the sustainability of the salmon aquaculture industry in North America. The vaccine could also form an integral component of adaptive management strategies for the protection and recovery of endangered Atlantic salmon in Maine.

Keywords:
isa virus; recombinant; vaccine; efficacy; antibody

Infectious salmon anemia (ISA) virus is an emerging pathogen of farmed Atlantic salmon (Salmo salar). The virus is among the fish pathogens listed in the Aquatic Animal Health Code of the Office International des Epizooties (OIE). As such, ISA is a notifiable disease and compulsory eradication policies are enforced worldwide. Control measures, such as an efficacious vaccine, would reduce the viral load in farm sites and could form an integral component of adaptive management strategies for the protection and recovery of endangered Atlantic salmon in Maine, stock enhancement and continued productive commercial and recreational fisheries. The goal of this project is to develop a safe, efficacious and cost effective recombinant vaccine using ISA virus antigens that we have identified as contributing to immunoprotection and to enhance the efficacy of the vaccine through optimization of the dose, formulation and antigen combination.