Background: Disialoganggioside GD3 is expressed on the surface of selected
cell types, Anti-GD3 mAb administered to human subjects with malignant mela
noma produces signs and symptoms of immediate hypersensitivity reactions.
Objective: The expression of GD3 by human mast cells was assessed during ma
st 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 e
xamined by using high-performance thin-layer chromatography.
Results: Flow cytometry showed that the percentage of GD3(+) cells increase
d in parallel to Kit(+) cells during the recombinant human stem cell factor
-dependent development of fetal liver-derived mast cells. Double-labeling e
xperiments showed that GD3(+) cells were also surface Kit(+) and granule tr
yptase positive, identifying them as mast cells in preparations of lung-, s
kin-, fetal liver-, and cord blood-derived cells. The major acidic glycolip
id detected was NeuAc alpha2-8NeuAc alpha2-3Gal beta1-4Glc beta1-1'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 bea
ds were used to purify mast cells to greater than 90% purity from dispersed
skin cells enriched to approximately 12% purity by means of density-depend
ent sedimentation but were less proficient for dispersed human lung mast ce
lls, 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.