Chewing stimulates secretion of human salivary secretory immunoglobulin A

Immunoglobulin A (IgA) is the most abundant immunoglobulin in saliva and ot her mucosal secretions and plays an important role in mucosal immunity. The present study examined whether secretion of IgA, like other salivary prote ins, is increased by reflex stimulation. Parotid saliva was collected from subjects into separate vials under resting conditions and during chewing-st imulated secretion over 45 min. Enzyme-linked immunosorbent assay (ELISA) i ndicated that chewing increased IgA secretion. The extent and pattern of th e increase were similar to those of total protein and acinar cell amylase. SDS gel electrophoresis and Western blotting showed that high-molecular-wei ght forms of IgA-containing secretory component predominated in all saliva samples. Secretory component, the cleaved epithelial receptor for polymeric IgA, was secreted in a pattern very similar to that of IgA. It is conclude d that chewing stimulates epithelial cell transcytosis of IgA and increases secretion of secretory IgA into saliva.