SULFATIDES TRIGGER CYTOKINE GENE-EXPRESSION AND SECRETION IN HUMAN MONOCYTES

We investigated whether sulfatides are able to trigger transmembrane s ignals and activation of selective cell functions in human monocytes. Sulfatides stimulated an increase in cytosolic free-calcium in monocyt es, and this depended on the release of calcium from intracellular sto res. Non-sulfated galactocerebrosides had no effect on monocyte cytoso lic free calcium. Sulfatides enhanced expression of tumor necrosis fac tor, interleukin-8, and interleukin-1 beta but not interleukin-12/natu ral killer cell stimulating factor mRNAs. Sulfatides also triggered se cretion of cytokines into the extracellular medium, although they were much less effective than lypopolysaccharide. Both enhanced expression of cytokine mRNAs and secretion by sulfatides required sulfation of t he galactose ring of the glycolipid as non-sulfated galactocerebroside s had no effect. These findings suggest that sulfatides that are relea sed at sites of inflammation can amplify the inflammatory reaction tri ggering cytokine expression in, and release by, monocytes.