IDENTIFICATION AND CHARACTERIZATION OF MYCOBACTERIUM-PARATUBERCULOSISRECOMBINANT PROTEINS EXPRESSED IN ESCHERICHIA-COLI

Mycobacterium paratuberculosis is the causative agent of Johne's disea se, a chronic enteritis in ruminants, and it has also been isolated an d identified from patients with Crohn's disease, an inflammatory bowel disease. The control of Johne's disease has been hampered by the lack of a reliable diagnostic test because of the large degree of antigeni c cross-reactivity between mycobacterial and non-mycobacterial species . To help identify specific antigen(s) or epitope(s), an M. paratuberc ulosis expression library was screened with antibodies and DNA probes. In total, 54 clones were randomly picked, purified, and characterized by DNA probes and monoclonal antibodies with known specificity to ind ividual mycobacterial antigens. Four clones carrying the heat shock pr otein 65K-, two representing the secreted protein 32K-, three represen ting the 21K-, and 20 clones representing the specific insertion eleme nt of M. paratuberculosis (IS900)-encoding genes and their gene produc ts were identified and characterized. Well-defined recombinant antigen s and/or epitopes representing M. paratuberculosis may facilitate the development of specific diagnostic tests and the investigation of thei r role in these chronic diseases.