Immunoglobulin A

Immunoglobulin A (IgA) is an antibody which plays a critical role in mucosal immunity. In its secretory form, IgA is the main immunoglobulin found in mucous secretions, including tears, saliva, colostrum and secretions from the genito-urinary tract, gastrointestinal tractprostate and respiratory epithelium. It is also found in small amounts in blood.