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Pacific GeneTech Demonstrates Safety of Proprietary Adjuvant in Dip/Immersion Vaccination of Rainbow Trout

1 November, 2022

Pacific GeneTech (PGT) reports successful results in a recent safety trial for its patented adjuvant delivery system, Hercules, when used as a vaccine component in a dip/immersion vaccination in rainbow trout.  The study was conducted at the University of Maine in the US.


The study was performed in rainbow trout (Oncorhynchus mykiss) with a range of Hercules dose concentrations and time exposures.  Flavobacterium psychrophilum was used as the inactivated antigen in this study. In general, fish are dipped or immersed in a defined dose of vaccine solution for defined periods of time. Dip or immersion vaccines are desirable in aquaculture settings as they can be administered to smaller fish, eliminate the need for anaesthesia and reduce handling stress. However, adequate stimulation of the immune response has been a primary challenge for this method of administration.


Results demonstrated that the Hercules vaccine formulations did not cause any significant observable adverse reactions in the rainbow trout by dip and by immersion. PGT will conduct challenge trials against Flavobacterium psychrophilum as a next step in the development of Hercules for fish vaccination, further broadening the applications of its adjuvant delivery system in vaccination against multiple pathogens in multiple host species.


Pacific GeneTech ( develops and commercializes next-generation vaccines and biologics for areas of high unmet or underserved needs in food safety and animal health. PGT's proprietary "Aegis" vaccine platform combines cross-protective antigens and immunopotentiators in PGT vectors for broad spectrum protection against multiple strains and species of infectious diseases. The PGT vaccines can be administered orally or by injection in both live and inactivated forms. PGT's "Hercules" adjuvant/delivery system provides enhanced efficacy of inactivated and its "Argo" yeast vector is a safe, flexible and robust carrier of immunogenic material.


PGT has out-licensed two of its leading poultry vaccines addressing economically important gastro-intestinal pathogens and has out-licensed its Hercules adjuvant for use in third-party vaccines. Vaccines for other pathogens and animal species are under development. PGT is developing other applications for its Hercules adjuvant/delivery system and for the Argo vector. PGT, through its affiliate company, PGTx, has commenced programs with collaborators addressing human dysentery.

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