The Role of TIM-4 in Food Allergy Hai Ning Shi, W. Allan Walker  Gastroenterology  Volume 133, Issue 5, Pages 1723-1726 (November 2007) DOI: 10.1053/j.gastro.2007.09.047 Copyright © 2007 AGA Institute Terms and Conditions

Figure 1 The intestinal epithelium is a single cell layer that forms the interface between the external and the internal environments of a host and separates luminal antigens (bacteria, bacterial products, and food) of the gastrointestinal tract from the largest population of lymphocytes in the body. The intestinal mucosal immune system plays an important role in the induction and maintenance of tolerance to food and other innocuous luminal antigens and in the protection of the epithelial barrier against pathogenic invasion. This function of the intestinal epithelial mucosal system is tightly regulated and can be influenced by effective antigen presentation and by the cytokine microenvironment. The T-cell stimuli derived from DCs therefore, include MHC II peptide (signal 1), the expression or absence of costimulatory molecules (signal 2), and the expression or absence of polarizing cytokines, which may provide an additional signal (signal 3). The induction of nonresponsiveness (tolerance) is thought to be mediated by clonal deletion, clonal anergy, and the generation of regulatory T cells producing IL-10 and/or transforming growth factor-β. Failure to precisely regulate the mucosal immune system may result in the development of mucosal inflammation and an allergic response. The bacterial superantigen SEB induces upregulation of TIM-4 on DC, which contributes to Th2 differentiation and the development of an allergic response. (Color version of this figure available online at www.gastrojournal.org) Gastroenterology 2007 133, 1723-1726DOI: (10.1053/j.gastro.2007.09.047) Copyright © 2007 AGA Institute Terms and Conditions