Isolation and characterization of serologically active phosphatidylinositol oligomannosides of Mycobacterium tuberculosis.

Phospholipids extracted with hot methanol from Mycobacterium tuberculosis, strain H37Rv, were fractionated with solvent mixtures and by partition chromatography on silica-gel columns. Of 12 components detected on a thin-layer chromatogram of the total phospholipid fraction, 6 components were purified. They were all phosphatidylinositol oligomannosides: two hexamannosides (H-2 and H-3), one tetramannoside (H-4), one trimannoside (H-5), and two dimannosides (H-6 and H-7). The molar ratios of fatty acid to phosphorus were 3 for H-2, H-4, H-5, and H-6, and 4 for H-3 and H-7. In each lipid, more than 80% of the total fatty acids were palmitic and tuberculostearic acids. Each of the six lipids had serological activity to various degrees.