Potent Vaccine Formulas for Johne`s Disease

Johne's disease (JD) is a contagious, chronic, and potentially fatal infection caused by Mycobacterium avium subsp. paratuberculosis (M. ap) affecting the small intestine of all ruminants, including dairy cattle. Infected cattle can suffer from chronic diarrhea, weight loss, reduced milk yield, and low, but persistent mortality, causing significant economic losses to the dairy industry, with estimated annual losses of $200 to $500 million in the USA alone. The licensed killed vaccine (Mycopar®) does not prevent infection and infected animals will continue to shed M. ap in their feces and milk. In this Phase I application, we will optimize the vaccine delivery route of a vaccine candidate in goats, as a first stage for further testing in a more expensive calf challenge model by 1) Optimize delivery route of Johne's Disease LAV candidate. We will optimize pgsN vaccine by testing its safety and immunogenicity in goats following oral delivery (vs. S/C injection) to develop a safe and more effective vaccine against JD. In addition, we will 2) Develop simple assays to differentiate between infected and vaccinated animals (DIVA) by taking advantage of the defined genetic mutation introduced in pgsN. Overall, the development of an efficient, safe and commercially viable vaccine against JD is an arduous and prolonged process. Our novel application of an oral vaccine and the development of sensitive DIVA assays will further improve our chances to commercialize PGS vaccines to the dairy operations in the USA and worldwide, a goal that is supported by USDA-SBIR program.