Molecular Mechanisms Controlling Immunoglobulin E Responses

Immunoglobulin E (IgE)-mediated allergic reactions comprise the classic type I immediate hypersensitivity reactions that occur within seconds to minutes of exposure to allergens or antigens. The ability of B lymphocytes to produce IgE in response to antigens relies on a complex set of molecular events, several of which have been delineated only recently. The Th type 2 cytokines IL-4 and IL-13 are the key mediators in Ig class switching to IgE and therefore are important for IgE-dependent mast cell degranulation. IgE production is the end result of highly coordinated and specific immune responses beginning with exposure to allergens in a genetically predisposed individual. The underlying mechanism that links these reactions is the binding of IgE to high-affinity Fc receptor on the surface of mast cells or basophils and crosslinking of FccRI/IgE complex by antigens.