Structure and antigenicity of the phosphorylated lipopolysaccharide antigens from the leprosy and tubercle bacilli.
A family of major arabinose- and mannose-containing phosphorylated lipopolysaccharides was isolated from Mycobacterium leprae and Mycobacterium tuberculosis. The only antigenic member of the family, lipoarabinomannan (LAM)-B, was purified by anion exchange and gel filtration chromatography in detergent and recovered in large quantities (15 mg/g of bacteria). It yielded a broad diffuse band on polyacrylamide gel electrophoresis but appeared homogeneous by this criterion and gel filtration. Besides arabinose and mannose, it contained glycerol and a polyol phosphate and was acylated by lactate, succinate, palmitate, and 10-methyloctadecanoate. The phosphate was released by alkalinolysis and identified by thin layer chromatography and gas chromatography-mass spectrometry as myoinositol 1-phosphate. Thus, the group-specific "arabinomannan" of the genus Mycobacterium in the native state is acylated, contains the substituents of phosphatidylinositol, and is apparently membrane associated. LAM-B is one of the dominant immunogens of the leprosy bacillus reacting readily with antibodies from lepromatous leprosy patients and monoclonal antibodies in plate and nitrocellulose enzyme-linked immunosorbent assay and on electrophoretic immunoblots. It is immunologically cross-reactive with a like product from M. tuberculosis. LAM-B is clearly the pervasive "glycoprotein" antigen of the leprosy bacillus and may be the long sought lipoteichoic acid-like polymer of Mycobacterium with a role in cell wall physiology, macrophage recognition, and perhaps an involvement in cross-protective immunity.
D000942:Antigens, Bacterial / Q000032:analysis; D001089:Arabinose / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D005227:Fatty Acids / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008070:Lipopolysaccharides / Q000032:analysis / Q000276:immunology*; D008358:Mannose / Q000032:analysis; D009166:Mycobacterium leprae / Q000276:immunology*; D009169:Mycobacterium tuberculosis / Q000276:immunology*
D000942:Antigens, Bacterial; D005227:Fatty Acids; D008070:Lipopolysaccharides; C050016:lipoarabinomannan; D001089:Arabinose; D008358:Mannose