Tuesday, October 6, 2009
A mast cell is a connective and fatty tissue cell which produces basophilic and cytoplasmatic granules which contain histamine and heparin, which play an important role during allergic reactions and inflammation response. Mast cells are derived from an undifferentiated precursor of monocytic origin in the perivascular connective tissue. During inflammatory processes, the mast cells releases their granules, as well as various hormonal mediators into the interstitium. Mast cells can be stimulated to degranulate by direct injury, cross-linking of Immunoglobulin E (IgE) receptors, or by activated complement proteins. Evidence suggests that mast cells have a fundamental role in innate immunity as they elaborate a vast array of important cytokines and other inflammatory mediators, expressing multiple pattern recognition receptors thought to be involved in recognizing broad classes of pathogens.