Food allergyOral tolerance and allergic responses to food proteinsStrobel, Stephan; Mowat, Allan McIAuthor Information aPeninsula Postgraduate Health Institute, Peninsula Medical School, Plymouth, UK bDivision of Immunology, Infection and Inflammation, University of Glasgow, Biomedical Research Centre, Glasgow, UK Correspondence to Stephan Strobel, MD, PhD, Peninsula Postgraduate Health Institute, John Bull Building, Peninsula Medical School HQ, Tamar Science Park, Research Way, Plymouth PL6 8BU, UK Tel: +44 1752 437470; fax: +44 1752 517842; e-mail: Stephan.Strobel@pms.ac.uk Current Opinion in Allergy and Clinical Immunology: June 2006 - Volume 6 - Issue 3 - p 207-213 doi: 10.1097/01.all.0000225162.98391.81 Buy Metrics Abstract Purpose of review The default response to protein antigens in the intestine is the induction of systemic and local hyporesponsiveness, ensuring the prevention of coeliac disease and food allergies. Interest is increasing in the role of dietary manipulation and probiotics in treating allergic and other diseases, but less is known about how these regimens might influence systemic and local immune responses. This paper addresses the mechanisms at the interface of innate and adaptive immunity that determine how the body responds to orally administered proteins and how local bacteria modify these. Recent findings This paper discusses evidence that dendritic cells in the intestinal mucosa are the critical cells that take up dietary proteins and migrate to the draining mesenteric lymph node, where they induce regulatory CD4+ T-cell differentiation. The properties of tolerized T cells are discussed and it is proposed that the gut microenvironment maintains homeostasis by conditioning dendritic cells to remain in a quiescent state. Inhibitory signalling by commensal bacteria possibly contributes to this process. Summary A regulatory network controls how dietary antigens are taken up and presented to T lymphocytes by specialized antigen-presenting cells. Elucidating their nature and how they are influenced by external factors such as probiotics may help develop novel therapies for allergy and help understand diseases such as coeliac disease. Copyright © 2006 Wolters Kluwer Health, Inc. All rights reserved.