Isolation and characterization of glycosphingolipids from human leukocytes a unique glycosphingolipid pattern in a case of acute myelomonoblastic leukemia

Abstract

Neutral glycosphingolipids and gangliosides were isolated from the malignant cells of a patient with acute myelomonoblastic leukemia. Structural analyses were performed by gas-liquid chromatography and by high-performance liquid chromatography combined with enzymatic hydrolysis of glycosphingolipids using glycosidases. We found that, in contrast to normal leukocytes and chronic leukemia cells which have only a single tetraosylceramide species, these acute myelomonoblastic leukemia cells have approximately equal amounts of both globo- and neolactotetraosylceramide. This is the first population of human leukocytes in which we found two families of neutral glycosphingolipids to be present. The ganglioside fraction was composed of appreciable quantities of both NeuAc α2 → 3Gal β1 → 4Glc β1 → 1Cer (GM3, hematoside) and NeuAc α2 → 3Gal β1 → 4GlcNAc β1 → 3Gal β1 → 4Glc β1 → 1Cer (sialoparagloboside). These cells did not have the ‘leukocyte-specific’ N-acetylneuraminosyllactotriaosylceramide found in normal human lymphocytes and neutrophils. These results are discussed in relation to normal leukocyte differentiation and acute leukemia. The present study also illustrates the usefulness of combining enzymatic degradation with high-performance liquid chromatography for glycosphingolipid structural determination.