Use of cell culture technology to minimize the needs for animal trials in development and production of fish vaccines

Niels Lorenzen

Prophylaxis of infectious diseases is better than cure, both in man and in husbandry animals. The latter also include aquacultured fish, where implementation of vaccines has contributed to a significant reduction in the needs for antibiotics. However, vaccine development as well as potency testing of already commercialized vaccines rely heavily on empirical vaccination and challenge (infection) trials with experimental fish.

The proposed project aims at substituting the use of live animals with cell cultures for the initial screening of vaccine components, before moving into animal experiments. Also, the project aims at establishing laboratory tests for confirmation of vaccine efficacy including batch potency testing.

Established cell cultures from different tissues of rainbow trout will be exposed to vaccine components and their response and uptake will be evaluated by gene expression and microscopical analyses, respectively.
The work will link up with previous and ongoing research projects for linking the results with data from fish trials. The project will thus by itself not require use of additional experimental animals.

The outcome of the project is expected to partly replace the use of live animals with cell cultures in initial steps of vaccine development and production. This will reduce the number of experimental animals needed within these fields. Refinement will be addressed by initial screening of vaccine components on cell cultures for potential toxic/negative side effects, hereby allowing avoidance of exposure of animals to potentially harmful elements.

Project status at January 2017

A panel of cell lines has been selected for the purpose of representing different tissue in the fish, for instance cells cultivated from the liver, intestines or immune cells from rainbow trout. A number of genes of importance to the immune response have also been selected. The initial cell line testing has been performed. Preliminary results: polylC is a known immune response stimulator as the system recognizes it as a sign of virus infection and thus a hazard indication. The below figure shows RTG-11 cells (gonad cells) stimulated with polyIC. The gene expression of a series of genes has been examined using Q-PCR.

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