Immunology and Immunopathology of the Intestines: A study of Stimuli Operative in the Release of Antibodies in the Rat Intestine

Abstract

We describe here a series of experiments which have been undertaken in the course of several years to try and study secretory mechanisms operative in the release of antibodies in the lumen of the intestine. The results of our experiments suggest that there are a number of stimuli that are efficacious in eliciting antibody release in the lumen of the rat intestine. These include the peptide hormones cholecystokinin and substance P, and cholinergic agonists such as pilocarpine. The fact that food has a similar effect indicates that the stimulation of antibody release is a physiological process co-ordinated with the ingestion of foreign antigens. We have also shown that food mediates its effect by means of cholecystokinin. Cholecystokinin promotes the release of antibodies belonging to the IgA, IgG, IgM and IgE isotypes. There is reason to believe that not all the IgA is secretory IgA. Antibody release can be inhibited by the CCK antagonist proglumide and by cholinergic antagonists. The intracellular messengers that participate in this process are changes in cytosolic calcium. It is proposed that the release of antibodies in the gastrointestinal tract is an active secretory process.