A glycolipid antigen specific to Mycobacterium paratuberculosis: structure and antigenicity

Mycobacterium paratuberculosis (National Animal Disease Center strain 18 and American Type Culture Collection strain 19698), the causative agent of Johne Disease (bovine paratuberculosis), contains a major immunoreactive glycopeptidolipid (polar GPL-I) that has been isolated and characterized. (formula; see text) Thus, the glycolipid antigen belongs to the polar mycoside C glycopeptidolipid family present in other mycobacterial species. The distal 2,3-di-O-methyl-alpha-L-fucopyranosyl-(1----3)-alpha-L-rhamnopyranosi de unit, the obvious antigen determinant, appears to be characteristic of M. paratuberculosis. The glycolipid can be recognized readily in isolates of M. paratuberculosis by TLC and its presence may be used as a characteristic marker of the infectious agent. The polar glycopeptidolipid was highly reactive in ELISA against serum from an animal hyperimmunized with M. paratuberculosis strain 18, indicating its basic immunogenicity.