Structures of the typing antigens of atypical mycobacteria: a brief review of present knowledge.

The overall structures of the typing antigens from serovars in the Mycobacterium avium-Mycobacterium intracellulare-Mycobacterium scrofulaceum complex have been elucidated. They are polar versions of the well-known C mycosides and have the general structure: [Formula: see text]. The lipopeptidyl-O-(3, 4-di-O-Me-Rha) "core" is common to all serovars; however, the oligosaccharide moiety is different. Detailed analyses of the oligosaccharides from selected serovars show that they contain four sugars at most. The same internal disaccharide residue [L-rhamnopyranosyl (alpha 1 leads to 2) 6-deoxytalose] is present in all oligosaccharides, whereas the outer one or two sugar residues are unique and apparently provide the distinctive features required for serological specificity.