In addition to its function as a central part of the digestive system, the intestinal epithelium
also forms a physical barrier between the antigen-rich gut lumen and the sterile core of the
body. The barrier function of the intestine is not only passive but is also manifested through a
highly specialized and expanded innate and adaptive mucosal immune system, that
provides immediate and effective immune protection at this critical entry site for pathogens. 1
Not all luminal antigens are harmful, however, and the induction and maintenance of …