IMMUNOGLOBULIN A

Immunoglobulin A (IgA) is an antibody and, in its secretory form, is the main immunoglobulin found in mucous secretions, including tears, saliva, colostrum, intestinal juice, vaginal fluid and secretions from the prostate and respiratory epithelium. It is also found in small amounts in blood. Because it is resistant to degradation by enzymes, secretory IgA can survive in harsh environments such as the digestive and respiratory tracts, to provide protection against microbes that multiply in body secretions.
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Immunoglobulin A n. Abbr. IgA The class of antibodies produced predominantly against ingested antigens, found in body secretions such as saliva, [more]Immunoglobulin A - Community and Resources

Noun
1. one of the most common of the five major classes of immunoglobulins; the chief antibody in the membranes of the gastrointestinal and respiratory tracts
(synonym) IgA
(hypernym) immunoglobulin, Ig, immune serum globulin, immune gamma globulin, immune globulin