The major goal of this project will be to identify gene and proteins related to the signal system of the fish immune system. Based on this we will develop methods to monitor the individual steps of the cascade following immune stimulation by various antig ens. The methods will be used to map the signal network of the fish immune system. As fish species we will focus upon Atlantie halibut and especially the response to viral infections (VER, IPN). The ultimate goal is to acquire knowledge making it possible to design, at a molecular level, vaccines with improved effects against viral diseases