Disialoganglioside GD3 is selectively expressed by developing and mature human mast cells

Abstract

Background: Disialoganglioside GD3 is expressed on the surface of selected cell types. Anti-GD3 mAb administered to human subjects with malignant melanoma produces signs and symptoms of immediate hypersensitivity reactions. Objective: The expression of GD3 by human mast cells was assessed during mast cell development in vitro and in samples of lung and skin. Methods: GD3 on tissue- and in vitro–derived mast cells was analyzed after double labeling of cells for tryptase (G3 mAb) or Kit (YB5.B8 mAb) and GD3 (R24 mAb). Glycolipids in extracts of fetal liver–derived mast cells were examined by using high-performance thin-layer chromatography. Results: Flow cytometry showed that the percentage of GD3+ cells increased in parallel to Kit+ cells during the recombinant human stem cell factor–dependent development of fetal liver–derived mast cells. Double-labeling experiments showed that GD3+ cells were also surface Kit+ and granule tryptase positive, identifying them as mast cells in preparations of lung-, skin-, fetal liver–, and cord blood–derived cells. The major acidic glycolipid detected was NeuAcα2-8NeuAcα2-3Galβ1-4Glcβ1-1′Cer (GD3). Among peripheral blood leukocytes, only basophils and about 10% of the T cells were labeled with anti-GD3 mAb. Anti-GD3 mAb–conjugated magnetic beads were used to purify mast cells to greater than 90% purity from dispersed skin cells enriched to approximately 12% purity by means of density-dependent sedimentation but were less proficient for dispersed human lung mast cells, most likely because of other cell types that express GD3. Conclusion: GD3 is expressed on the surface of developing human mast cells in parallel to tryptase in secretory granules and, like Kit, can serve as a target for their enrichment by immunoaffinity techniques. (J Allergy Clin Immunol 2001;107:322-30.)