Activating and Inhibitory Receptors on Mast Cells

Abstract

Definition Cell activation results from the transient displacement of a balance of positive and negative signals that are constitutively generated in resting cells. This physiological balance can be displaced when cell surface receptors are engaged by extracellular ligands. Mast cells express a variety of membrane receptors that control the biological responses of these cells. These include activating receptors and inhibitory receptors. Activating receptors positively regulate biological responses of mast cells. Receptors for the Fc portion of immunoglobulins (FcR) such as high-affinity IgE receptors (FceRI) trigger an array of secretory responses including the exocy-tosis of preformed mediators, the generation of arachidonic acid-derived eicosanoids, and the secretion of cytokines, chemokines, and growth factors. FceRI do not trigger proliferative signals.