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Abstract In this study, some M. bovis cell extract antigens “sonicated antigen (SA)”, culture filtrate antigens ”short term culture filtrate (ST-CF)” and tuberculin were prepared from 29 mycobacterium isolates after the bacteriological examination of 39 tuberculin positive animals which tested from El-Sharkia and El- Menofia governorates by cultural methods. Microscopic examination was conducted for all 39 tuberculous lesions by using Ziehl-Nelseen stain and 27 were positive with a percentage of 69.23%. Real time PCR was carried out on all 29 isolates for identification of recovered colonies and all were identified as Mycobacterium bovis with a percentage of 100%. Extraction of M. bovis with sonication resulted in the recovery of 1.3 mg/ml of soluble protein in the sonicated extract and the protein concentration of M. bovis ST-CF at 2nd week of growth was 2.7 mg/ ml. In addition, the protein concentration of M. bovis prepared tuberculin was 2.0 mg/ml and 1.0 mg/ml of offered PPD. SDS-PAGE was applied for characterization of antigenic extracts and CF of M. bovis and Western blotting analysis was performed. The use of ELISA on serum samples collected from the 1540 cows, before being tested by SICTT, revealed that 131 (8.51%) animals were positive to bTB by using PPD, 139 (9.03%) by using the commercial mixture antigen, 120 (7.79%) by using SA, 125 (8.12%) by using ST-CF and 133 (8.64%) positive animals by using prepared tuberculin, indicating that the use of mixture antigen could help to give more accurate diagnosis. This study proved that the superiority of ST-CF, prepared bovine tuberculin over SA extracts using ELISA in distinguishing between infected and non-infected cattle. Antigenic extracts of M. bovis SA also culture filtrate antigens ST-CF in addition to prepared tuberculin and PPD have the ability to differentiate between infected and non-infected animals on the basis of humoral immune response. Therefore these proteins may be useful as specific antigens for diagnosis of bovine tuberculosis by measuring humoral immune response using ELISA. |