الفهرس 
قرار لجنة الفحص و المناقشةOnly 14 pages are availabe for public view
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Abstract
ESAt-6 is a secreted protein present in the short term culture filtrate of M. tuberculosis after growth on synthetic Sauton medium. It induces high potent T-cell response and production of IFN- which play a critifica role in protective cell mediated immunity against tuberculosis. Its corresponding gene is located in RD1 deleted in BCG vaccine. DNA encoding ESAT-6 of M. bovis was inserted into a bacterial expression vector of PQE16 and PQE50 resulting in 6XHis esat-6 fusion gene construction. This plasmid was transformed into E. coli and effectively expressed using IPIG. The recombinant protein was purified by Ni-NTA column. Fifty Guinea pigs were divided into 5 groups and vaccinated with different vaccines and –ve control group then challenged with M. bovis. Immunogenicity of vaccine is applied by ELISA technique then measured cell mediated immunity by Brdu ELISA kits. Other investigations including histopathology for lung and spleen and protection against infection with M. bovis was monitored by: higher survival rate, decrease viable bacterial count of M. bovis in lung, spleen, decrease lung density and decrease root specific lung weight. So, ESAT-6 has major potency than BCG vaccines in vaccination against bovine tuberculosis and recommended to be used in large animals.