Mast cells and basophils share common mechanisms of function.
Both have receptors with an affinity for the Fc region of IgE antibody. The antibody is produced by plasma cells on re-encountering a particular foreign antigen to which they have previously been primed. The antibody, specific to the antigen, passes to mast cells in connective tissue or basophils in blood.
At the surface of the cell, the antibody bridges two membrane-bound receptors. This triggers, via secondary messengers, elevation of calcium within the cell and degranulation of the cytoplasm.
Within the granules are an array of inflammatory mediators; also, arachidonic acid metabolites are newly synthesized e.g. leukotrienes B4, C4 and D4; prostaglandins and thromboxane.
The histological effect is to encourage increased transit of newly-activated inflammatory cells and cytokines to the area, and to promote vasodilatation, vasopermeability and bronchoconstriction. Extremes of the response can manifest clinically as atopic allergy and type I hypersensitivity.
Last reviewed 01/2018