Antigen processing and presentation by intestinal epithelial cells - polarity and complexity

The mechanisms by which gut-associated lymphoid tissue (GALT) maintains a balance between oral tolerance and active immune response in the face of exposure to high antigen concentrations remains a central question in mucosal immunity. Here, Robert Hershberg ann colleagues discuss the evidence that human intestinal epithelial cells function as antigen-presenting cells (APCs) capable of regulating T-cell responses in the intestinal mucosa.