Immunisation strategies against viral pathogens of Atlantic salmon

This project will build a knowledge platform where the aim is create a basis for development of efficacious virus vaccines for Atlantic salmon. Vaccines that confer good protection against bacterial diseases have been developed, the challenge lies in obta ining equal protection against major viral diseases. The trade-off for the bacterial vaccines lies in their reactogenic potential, resulting in tissue damage and possibly too strong danger signals at the injection site. The big question for vaccine develo pment against virus infections is to understand the principal difference between inferior protection obtained by inactivated vaccines and the strong immunity induced by replicating variants. The platform will develop methods for directing the immune respo nses and methods whereby we can profile them. This will be achieved through rational design of nanoparticle based vaccine formulations with balanced delivery of antigen and danger signals by combining antigens with ligands for Toll-like receptors or direc ting antigens to APC. Replicating vaccines will be developed by use of reverse genetics for IPN virus and PD virus, the latter will also be examined for its potential as a virus vaccine vector carrying foreign peptides of other viruses (IPNV as an example ). Profiling of immune responses in the host is a limiting factor in fish immunology. Cloning and sequencing of several salmonid cytokines has made it possible to monitor the responses in more detail. Immune profiling will include real-time PCR methods. M ethods for assessing cell-mediated responses will also be included. The outcome of these endeavours will hopefully be new tools for designing and assessing responses to virus vaccines in salmonids