secretory component
(SC) a 70,000 dalton glycopeptide occurring in secretory IgA; synthesized not by the plasma cell producing the IgA but added while the IgA is crossing the epithelium; it may protect secretory IgA from proteolytic attack after secretion, or it may play some role in the process of secretion. Secretory component deficiency has been seen in a few patients; there is complete lack of IgA in external secretions although serum IgA is normal. Called also secretory piece.
Medical dictionary.
2011.