Identification of in vivo induced antigens of the malacosporean parasite Tetracapsuloides bryosalmonae (Cnidaria) using in vivo induced antigen technology

is a malacosporean endoparasite that causes proliferative kidney disease (PKD) in wild and farmed salmonids in Europe and North America. The life cycle of completes between invertebrate bryozoan and vertebrate fish hosts. Inside the fish, virulence factors of are induced during infection or interactions with host cells. genes expressed are likely to be important in fish pathogenesis. Herein, we identify induced antigens of during infection in brown trout ( ) using induced antigen technology (IVIAT). Brown trout were exposed to the spores of and were sampled at different time points. The pooled sera were first pre-adsorbed with antigens to remove false positive results. Subsequently, adsorbed sera were used to screen a cDNA phage expression library. Immunoscreening analysis revealed 136 immunogenic proteins induced in brown trout during parasite development. They are involved in signal transduction, transport, metabolism, ion-protein binding, protein folding, and also include hypothetical proteins, of so far unknown functions. The identified induced antigens will be useful in the understanding of pathogenesis during infection in susceptible hosts. Some of the antigens found may have significant implications for the discovery of candidate molecules for the development of potential therapies and preventive measures against in salmonids.