Interactions between Epithelial Cells and Dendritic Cells in Bacterial Handling

The role of the intestinal microflora in the development and correct functionality of the immune system is becoming increasingly evident. A perturbation of the gastrointestinal microflora or unwanted immune responses to this flora have been demonstrated to play a critical role in the pathogenesis of inflammatory bowel disease (IBD) in experimental animal models but recently also in tumorigenesis. It has been proposed to modify the intestinal microflora via the administration of probiotics in IBD patients. In order to better understand how probiotics could be beneficial to the host, it is important to understand how bacteria are handled at mucosal surfaces and how dendritic cells and epithelial cells communicate with each other to 'tolerate' the intestinal flora. This article is intended to summarize recent advances on the function of gut immune cells and on some of the features that have been documented on the immunophenotypic characteristics of some probiotic strains.