RAPID COMMUNICATION Differential Release of Mast Cell Interleukin-6 Via c-kit

Mast cells represent a potential source of interleukin-6 (ILlenge with SCF, bone marrow-derived cultured mouse mast 6) and other cytokines that have been implicated in host cells (BMCMCs) released amounts of IL-6 that were greater defense, tissue maintenance/remodeling, immunoregulathan 100-fold more than those produced by unstimulated tion, and many other biologic responses. In acquired imcells, but that were substantially less than those produced mune responses to parasites or allergens, the extensive IgEin response to IgE and specific antigen. Moreover, BMCMCs dependent activation of mast cells via FceRI can result in the released IL-6 upon challenge with concentrations of SCF that release of large quantities of biogenic amines that are stored resulted in little or no detectable release of tumor necrosis in the cells’ cytoplasmic granules as well as the production factor-a, leukotriene C4, histamine, or serotonin. These findof lipid mediators and many cytokines; these products toings indicate that SCF, a widely expressed protein that is gether can orchestrate an intense inflammatory response. critical for mast cell development and survival, can also reguWe now report that activation of mouse mast cells via c-kit, late the differential release of mast cell mediators. the receptor for the pleiotropic survival/growth factor, stem q 1997 by The American Society of Hematology. cell factor (SCF), can induce the release of IL-6. Upon chal-