Isolation of tissue mast cells.

Located primarily in tissues, mast cells are one of the principal effector cells in allergic inflammation. Mast cells derive from mononuclear precursor cells which undergo their final phase of differentiation in the tissues. Mast cells express a unique set of proteases and display functional diversity depending on the tissue in which they differentiate--a phenomenon often referred to as mast cell heterogeneity. Enzymatic digestion and density centrifugation have often been used to isolate human mast cells from tissues such as lung and skin, frequently resulting in cells with low viability and purity. Here, we describe a protocol that combines gentle enzymatic digestion with positive selection techniques to isolate reasonably viable and substantially enriched preparations of tissue mast cells.