Mast cell activation and effector function

Mast cell activation and effector function refers to the physiological and pathological processes by which mast cells, specialized granulocytes of the innate immune system, respond to stimuli to release inflammatory mediators. The most well-characterized activation pathway is the Type I hypersensitivity reaction, mediated by the cross-linking of allergen-specific immunoglobulin E (IgE) bound to the high-affinity IgE receptor (FcεRI) [1][3]. Upon activation, mast cells undergo rapid degranulation, releasing preformed mediators such as histamine, heparin, and neutral proteases like tryptase, which induce vasodilation and bronchoconstriction [2][4]. This is followed by the de novo synthesis of lipid mediators (e.g., leukotrienes and prostaglandins) and a variety of pro-inflammatory cytokines and chemokines [3]. While these functions are essential for host defense against parasites and the neutralization of venoms, dysregulated mast cell activation is the primary driver of allergic diseases, asthma, and systemic anaphylaxis [4][6]. Therapeutic intervention typically involves mast cell stabilizers like cromolyn sodium, monoclonal antibodies such as omalizumab that sequester IgE, or small-molecule inhibitors targeting essential signaling kinases like KIT, SYK, or BTK [5].

Other names

Mast cell degranulationMast cell-mediated immune responseType I hypersensitivity pathwayMast cell activation syndrome (MCAS) pathway

Inhibition of IgE binding to the high-affinity IgE receptor (FcεRI), stabilization of the mast cell plasma membrane to prevent degranulation, and inhibition of intracellular tyrosine kinases (e.g., KIT, SYK, BTK) required for signal transduction [5].