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a polypeptide chain found in external secretions (for example, tears, saliva, colostrum) associated with immunoglobulins A and M. It also may occur in free form but when attached to dimeric IgA, it facilitates transport across the mucosal epithelial surface. The secretory piece is derived by proteolytic cleavage of the immunoglobulin receptor on epithelial cells.
a glycopeptide that is attached to immunoglobulin A (IgA). It is necessary for the secretion of IgA into mucosal spaces.
pertaining to secretion.
the specialized cells in a secretory gland that perform the secretory function.
a polypeptide synthesized by epithelial cells that binds to IgA to form secretory IgA (SIgA).
see secretory diarrhea.
intracellular granules composed of secretory proteins after their conversion by the Golgi apparatus.
secretory IgA (SIgA)
a class of immunoglobulin found in some body secretions, e.g. saliva, respiratory secretions, milk and colostrum, that is responsible for local immunity. See also immunoglobulin.