Comparative studies of antigenic glycolipids of mycobacteria related to the leprosy bacillus

The leprosy bacillus, Mycobacterium leprae, is a member of a small group of mycobacteria comprising the species Mycobacterium bovis, Mycobacterium marinum, Mycobacterium kansasii, Mycobacterium tuberculosis, Mycobacterium ulcerans and related taxa. This relationship is based on the similarity of the characteristic lipid types in the cell envelope. Mycobacterium leprae produces a phenolic glycolipid antigen which is species specific. This communication reports a comparison of the specificity of the lipid antigens of other members of this group of mycobacteria. Mycobacterium kansasii, in accordance with previous studies, produces phenolic glycolipid and trehalose-based lipooligosaccharide antigens which do not cross react with antisera raised against other mycobacteria. The phenolic glycolipid and an uncharacterised polar glycolipid, with the properties of a lipooligosaccharide, from Mycobacterium marinum are also shown to be specific antigens. An acylated trehalose glycolipid antigen from Mycobacterium tuberculosis H37Rv reacts strongly with antisera raised against the same strain and sera from eight out of ten tuberculosis patients. The phenolic glycolipid antigen, isolated only from Mycobacterium tuberculosis "Canetti" variants, did not react with antisera raised against the type strain, Mycobacterium tuberculosis H37Rv, although it had been shown previously to react with sera from tuberculosis patients. It is apparent that there are populations of the tubercle bacillus which differ in the lipid antigens expressed on their cell surface.