Ingestion of innocuous antigens, including food proteins, normally results in local and
systemic immune nonresponsiveness in a process termed oral tolerance. Oral tolerance to
food proteins is likely to be intimately linked to mechanisms that are responsible for
gastrointestinal tolerance to large numbers of commensal microbes. Here we review our
current understanding of the immune mechanisms responsible for oral tolerance and how
perturbations in these mechanisms might promote the loss of oral tolerance and …