FIELD STUDIES ON THE PREPARED INACTIVATED GAMMA IRRADIATED BRUCELLA ABORTUS VACCINE IN CATTLE

This work aims to investigate the safety, immunogenicity, and protective immunity of gamma-irradiated B. abortus vaccine prepared from a local Egyptian field isolate (B. abortus biovar 9) in cattle calves as a potent alternative vaccine to protect cattle from brucella infection. It was found that the vaccine was safe for guinea pigs as a laboratory model and for cattle calves at a dose of ~ 5 x 1010 CFU/2ml.The immune response of cattle calves was evaluated for the irradiated B. abortus vaccine at a dose of ~ 3 x 109 CFU / 2ml and 5 x 1010 CFU / 2ml. The humoral immune response was monitored by RBAT, BAPA, and ELISA test. It was found that, the irradiated vaccine at a dose of ~ 5 x 1010 CFU achieved protective immunity at 4th week postvaccination (WPV) 0.7 . ELISA antibody titer reached peak titer at 12th WPV (1.37) in INF-g assay irradiated vaccine in dose of ~ 5 x 1010 CFU achieved a cut-off value 35th day (5.3 SI) post vaccination and peak value was reached on the 60th day post vaccination (5.5 SI) in blood samples of the vaccinated cattle calves Group 1 (G1). Therefore, it was concluded that irradiated B. abortus vaccine in a dose of ~ 5 x 1010 CFU is safe, immunogenic, and protective vaccine to protect cattle against brucellosis.