Mast cells are activated by cross-linking of the high-affinity FcεRI receptor, initiated by the
binding of multivalent antigen to prebound IgE molecules in the receptor complex. Once
activated, mast cells elicit three types of biological responses:(i) secretion of preformed
granules,(ii) synthesis and secretion of cytokines, and (iii) synthesis of lipid mediators. These
responses form the basis of one of the most potent effector systems in immunity—immediate
hypersensitivity—which includes, in the most extreme cases, anaphylaxis. The speed and …