Mast Cells in Allergy, Host Defense, and Immune Regulation

Mast cells are long-lived resident tissue cells found at sites that interface with the external environment, such as the skin, airways, and gastrointestinal tract. Mast cells are known to be critical for many aspects of allergic disease, through IgE-mediated release of preformed, granule-associated mediators such as histamine and proteases as well as production of lipid mediators such as LTC₄ and PGD₂. Mast cells also produce a wide range of cytokines and chemokines. Through such mediators they can influence immune regulation, including the mobilization of dendritic cells. Closely associated with blood vessels, these cells may be particularly important in the early recruitment of immune cells to sites of tissue damage and infection and can be activated by multiple pathogen-associated pathways. They produce unique profiles of mediators in response to viral and bacterial infection, and have a crucial role in defense against several parasites. Mast cells have also been shown to regulate angiogenesis and tissue remodeling in chronic inflammation and cancer. Through the use of mast cell-deficient mouse models and the study of human mast cells we are developing a better understanding of how these cells might be targeted for therapy in a variety of diseases.