Host-virus interactions in Atlantic salmon

Infectious pancreatic necrosis virus (IPNV) and infectious salmon anemia virus (ISAV) are viruses causing threatening diseases in Norwegian aquaculture. Certainly, one of the most challenging problems in designing control strategies against these viruses is to define the specific factors, both in host and virus, required for virus replication and persistence. The overall goal of the project is to advance the understanding of antiviral defence mechanisms in salmon, the virulence mechanisms of the viruses, and host-virus interactions. The interferon (IFN) system of vertebrates plays a crucial role in the innate immune responses against virus infections. This project aims at advancing our understanding of the salmon IFN system by expression and activity st udies of newly discovered IFNs as well as through functional studies of receptors and signalling proteins involved. Furthermore, studies of the cellular host immune responses, aimed at dissecting the presentation of viral antigens to T-cells, will be made possible by development of monoclonal antibodies and tetramer technology. The yeast-two hybrid system combined with pull-down experiments will be used to examine potential interactions between the IPNV proteins, the ISAV proteins and to ma p interactions between viral and host proteins. For both ISAV and IPNV development of recombinant viral systems will be continued representing optimal tools for studying the function of viral genes, including viral virulence factors, as well as enabling d esign of "safe" attenuated vaccines. Equally, will continued studies of MHC peptide antigen presentation provide knowledge about viral epitopes optimal for inactivated and recombinant viral vaccines. RNA interference, including optimalisation for use in s almonid cells, will be implemented in the functional studies.