Characterization of cytostatically active glycosphingolipids isolated fromthioglycollate-elicited murine macrophages

Two acidic glycosphingolipids (gangliosides) derived from mouse macrophage membranes and separated by thin-layer chromatography have a strong cytostat ic effect on human and mouse tumor cells. The structure of the two ganglios ides, named Tc M phi G1 and M phi G2, was elucidated by application of phys icochemical and immunochemical methods. Gas chromatography and mass spectro metry of M phi G1 and M phi G2 classified them as isomeric monosialoganglio sides with ceramide moieties composed of sphingosine as the long-chain base , C-16 and C-18 fatty acids, respectively, and a lacto-tetraose backbone. F or M phi G1, additional immunochemical findings led to the proposed structu re IV(3)NeuAc-nLcOse(4)Cer. The immunochemical reactions of M phi G2 sugges t a branched structure for the oligosaccharide moiety.