Vaccines for chronic viral pathogens in salmon- generation of interferon attenuated cell lines. Acroym: SalVacCell Project goal / key aims. There is a major requirement to generate new vaccines for viral pathogens in the salmon aquaculture industry. Viruses represent one of the major economic losses to the salmon industry, which is a direct reflection of the lack of highly protective vaccines. In order to improve vaccine design and testing high quantities of viruses are required, but at present this is not possible. This project will use cell lines that have been edited by CRISPR/cas9 to be highly permissive for growth of difficult to grow viruses. We will knockout the type I interferon pathway which is the major antiviral mechanism in animals. Specifically we will target key genes that regulate interferon induced cellular responses to viral infection. These cell lines will additionally be used to explain the underlying function of genes associated with natural viral resistance / susceptibility in salmon that is of direct importance to breeding programs. We have secured Industrial partners Benchmark (vaccine company) and Landcatch (fish breeding). Consortium agreements will clearly define roles and confidentiality of IP. OBJECTIVES 1. Development of IFN-deficient fish cell lines by knock-out of IFN function 2. Evaluation KO cell lines to mount an antiviral response to confirm phenotype 3. Use the cell lines to explain naturally occurring resistance / susceptibility to fish viruses 4. Comparison of yield for viral particle production and viral diagnostic turn-over time between traditional cell lines and newly developed cell lines KEY CHALLENGES The overarching challenge is to be able to produce high titres of virus for vaccine companies to be able to improve design and protection to economically important chronic viral pathogens. Many labs have attempted to knock down genes in salmonid cells, but to date this has not been achieved. To our knowledge we are the first to create such cell lines and as such our unfunded preliminary work has already overcome a major hurdle. The challenge of this project is to fully exploit our cell line technology for both disease management and also to greatly improve the basis of genetic selection. Deliverables- to be used by partners a. Engineered cell lines that are deficient in antiviral responses. b. Cells lines that can be used to produce high titre of viruses for vaccines c. Capacity to upscale viral production in industrial environment. d. Improved precision of selection for disease resistance in salmon breeding Project duration: 24 months Total project cost: £354622 Contribution requested from (100%) BBSRC/NERC £249,622 (£199697.60 80%) Contribution from MSS: secured £65K Contribution from Benchmark secured £20K Contribution from Landcatch secured £20K