Immunity to Flavobacterium Psychrophilium Antigens and Development of a Coldwater Disease (CWD) Vaccine

NON-TECHNICAL SUMMARY: Economic impacts due to coldwater disease (CWD) have dramatically increased in recent years at public and private aquaculture facilities and CWD is the number one disese problem in the commercial rainbow trout industry in Idaho. In the United States, antibiotics available for the therapeutic treatment of fish with this disease are very limited and not expected to increase. Vaccination against this disease would provide the most benefit to aquaculturists through prevention of epizootics and a subsequent decrease in the need for antibiotic treatment. The Phase II studies are essential to provide a better understanding of the undrlying mechanism(s) involved in a protective immune response against Flavobacterium psychrophilum. This work will provide the foundation for the development and commercialization of a vaccine against CWD in Phase III.

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APPROACH: The Phase II project will continue to focus on F. psychrophilum strain CSF 259-93. To determine if protection can be achieved at a level needed for the development of an effective CWD vaccine, we must first confirm that protein or carbohydrate (LPS) components are responsible for the protection observed in the Phase I experiments. Since LPS was identified in Phase I as a likely vaccine candidate, vaccination experiments will focus on this bacterial component. LPS preparations will be tested for their ability to protect against disease challenge, and in parallel with these experiments we will determine what protein components (if any) are involved. Should the LPS experiments fail to provide high levels of protective immunity then immunoreactive proteins (once identified by Western blot) in the 70-100 kDa range can be targeted for recombinant expression and testing in-vivo.