IPNV Submit Vaccine: Optimization of Production and Vaccination of Salmonid Fish

Infectious pancreatic necrosis virus (IPNV) causes an economically significant, untreatable disease in young salmonid fish. A recombinant IPNV subunit vaccine (pTA1) has been developed and consists of a lysate of Escherichia coli cells that expressed IPNV VP2, NS and VP3 proteins. The Phase I research confirmed that the recombinant pTA1 vaccine was effective in laboratory scale trials and indicated that this vaccine construct was the most potent. Vaccines containing the VP2 gene or the 5' end of the VP2 gene induced intermediate and no protection, respectively. The pTA1 vaccine protected fish against two heterologous IPNV isolates in the West Buxton serotype and was more efficacious when prepared from a bioreactor culture versus shake cultures. The Phase II research will investigate three areas critical to the production of a commercial IPNV vaccine. These areas include: optimization of the conditions for bacterial growth and fusion protein induction; development of a standard vaccination protocol for use at hatcheries through optimization of vaccination parameters; and development of an in vitro ELISA potency test. Vaccine efficacy will also be evaluated in three species of salmonid fish against several IPNV isolates belonging to different serotypes and tested under field conditions.