Mycobacterium avium subsp. paratuberculosis (Map) strain Kag-1 which had been isolated in Japan and adapted to a protein free medium was compared immunologically and genetically with Mycobacterium strain 18 which is currently used for the production of diagnostic antigens of bovine paratuberculosis. Antigens prepared from strain Kag-1 induced a delayed-type hypersensitivity response and interferon-gamma induction comparable to those of strain P-18. The immunological and genetical characterization of strain Kag-1 indicated higher similarity to the reference strain of Map than that of strain P-18. Strain Kag-1 may have promise as a candidate strain to improve the diagnostic antigens for bovine paratuberculosis. (Immune System Section, Department of Immunology Tel +81-29-838-7857)
