Protective Efficacy of Chitosan Coupled Johne’s Disease Vaccine

Background: Johne’s disease (JD) is a chronic, economically important disease of domestic ruminants. Continuous efforts are being made to develop a potent vaccine for JD which confer a longer immunity. The present study was aimed at developing chitosan nanoparticles coupled JD vaccine and assess its efficacy.Methods: Potency of a heat killed, chitosan nanoparticle coupled JD vaccine developed with an Indian isolate of Mycobacterium avium subsp paratuberculosis (MAP) was tested in 107 goats. Pre and post immunization blood samples were collected at different time points and peripheral blood mononuclear cells were used for assessing IFN-γ, IL-2, IL-10 and IL-12 gene expressions. Immunized animals were challenged with a field isolate of MAP and the immune response was assessed.Result: Immunized goats were safe with no untoward reactions. Cytokine gene expression studies indicated a good Th1 response during 3-14 wk post immunization. The initial Th1 response was followed by a good Th2 response with a better IL-10 response than the IFN-γ and IL-2 responses in vaccinated animals at 23 wk PI. Both Th1 and Th2 responses were significantly higher in immunized animals at 23 and 34 weeks post challenge indicating a protective immune response.