Field evaluation of inactivated Corynebacterium ovis vaccine in sheep prepared from a local isolate
2016
Nabila A. Ghazy | Mohamed G. Abdelwahab | Makhareta M.A.M. | Abdallah Y.A.
Corynebacterium pseudotuberculosis vaccine was prepared from a local field isolate. Vaccination of sheep with 50g PLD toxoid and 10 mg bacterin adjuvanted with Montanide oil improved the levels of immune responses of sheep. In many countries, inactivated C. pseudotuberculosis adjuvant vaccines have been used for prevention and control of caseous lymphadenitis in sheep. However, the efficacy was variable. The aim of the present study was directed to prepare and evaluate the potency of an inactivated C. pseudotuberculosis vaccine using Montanide ISA206. Sheep were vaccinated with 1st dose of 2ml containing 10 mg bacterin and 50g toxoid and Montanide ISA 206 oil adjuvant and boostered with the same dose 15 days Apart. Evaluation of post vaccinal cellular immune response with lymphocyte proliferation assay and humoral immune response using ELISA was carried out. Cell mediated immune response of vaccinated sheep reached its peak 0.445 by 1st week post the second vaccination. The level of humoral immune response showed optical density of 1.005 by 1st week post the second vaccination. Challenge test was done in all sheep four weeks after the second dose of vaccination. Three sheep from vaccinated and three sheep from non-vaccinated groups were slaughtered and necropsied 150 days post challenge. The results revealed 75% protection percentage against challenge while unvaccinated challenged sheep showed 9% protection. Statistical analysis indicated that the vaccine assessed a significant level of cellular and humoral immunity.
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