Polar Mycosides C Antigenic Glycopeptidolipids

The polar mycosides C isolated from mycobacteria serovar 14 and 25 contained an unusual amino sugar which had been isolated previously from the lipooligosaccharides of M. kansasii and called kansosamine. Its 

MAIS serovars Oligosaccharidic chains, linked to hydroxyl 3 of L-Rhap-(al-2)-6-deoxy-L-talose References 

12 4-(2 hydroxy)propionamido-4,6-dideoxy-3-OMe D-Glcp-(pi-3)-4-0-Me L-Rhap-(al-3)-L-Rhap-(al- (208) 

As the polar mycosides C behave as antigens they must be located in the outer layers of the mycobacterial cell. In fact their external location was demonstrated in M. intracellulare by the use of ferritin-labelled antibodies 214). It has long been known that mycobacteria of the MAIS complex are surrounded by an electron-transparent zone when ultra-thin sections of infected host tissues are examined under the electron microscope. This zone is essentially composed of parallel fibrils wrapped longitudinally around the bacterium. This material was isolated by the use of urea density gradients and analyzed chemically. The three amino acids characteristic of mycosides C and alaninol as well as 6-deoxytalose were identified 194). This material consisted mainly of a mixture of polar and apolar mycosides C, in a ratio about 7 3 (275). 

Polar mycosides C from serovars 4 and 20 were prepared in radioactive form by growing suitable strains of M. avium on media containing [6- H]-fucose, [2- H]-mannose or [methyl- H]-methionine, in order to study their behaviour inside macrophages 216). 

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