Signal Transduction from the High Affinity IgE Receptor

Mast cells and basophils synthesize and store histamine, proteoglycans, and proteases in their granules and have surface receptors (FceRI) that bind IgE with high affinity. The interaction of multivalent antigen with this cell-bound IgE results in aggregation of FceRI and activation of the cells to release an array of inflammatory mediators. These mediators include the granular contents, arachidonic acid from phospholipids produced by the action of phospholipase enzymes, and cytokines such as tumor necrosis factor (TNF-α). Unlike the rapid release within minutes of preformed mediators, release of most cytokines is a slow process that requires several hours. This chapter reviews the current understanding of these intracellular pathways; most of this information is based on studies with the rat basophilic leukemia RBL-2H3 cultured mast cell line.