Comparison of Cattle Serum Antibody Responses to Five Different Mycobacterial Antigens in an ELISA System

The presence of common zoonosis diseases caused by Mycobacterium tuberculosis complex (MTBC) and nontuberculous mycobacteria (NTM), such as Johne's and Crohn's diseases, poses a public health threat and economic losses to Iranian livestock. Therefore, the early detection of mycobacteria is of paramount importance. In this regard, enzyme-linked immunosorbent assay (ELISA) is a new, simple to use, rapid, and useful diagnostic tool. This study was performed to evaluate different crude antigens obtained from Mycobacterium species using an indirect ELISA test to identify the mycobacterial infection in infected livestock. Five different strains of Mycobacteria including M. tuberculosis, M. phlei, M. bovis, M. avium subspecies paratuberculosis, and M. bovis AN۵ were cultured. The crude antigens in the samples were precipitated with trichloroacetic acid ۴%. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis of crude antigens isolated from different Mycobacterium species was reported. The total level of protein was determined by the Lowry protein assay. After the crude antigen preparation, the ELISA test was performed and the results were compared with the purified protein derivative skin test. Data analysis was performed using SPSS software version ۲۵. All five strains were detected in more than ۹۲% of healthy animals. The highest sensitivity of ELISA tests was in M. bovis AN۵ antigen which was greater than ۸۳%. The highest diagnostic specificity and efficiency of assays were in M. avium subspecies paratuberculosis which was ۹۵.۸۳% and over ۸۳%, respectively. Regarding the results, M. avium subspecies paratuberculosis and M. bovis AN۵ antigens were promising candidates for the design of diagnostic ELISA due to their sensitivity, specificity, and efficiency.

کلیدواژه ها:

Mycobacteria ، Nontuberculous mycobacteria ، Purified protein derivative test ، Enzyme-linked immunosorbent assay