IMMUNOLOGICAL INFLUENCES ON INTESTINAL PROLIFERATION AND DIFFERENTIATION

Intestinal epithelium has the property to renew very quickly. The cryp ts present at the base of the villi contain stem cells that give rise to the different cell types present in the intestinal epithelium. Stem cells have a high proliferative activity with a small mitotic potenti al. As the cells migrate along the villi they differentiate and acquir e intestinal properties. It was previously thought that intestinal dif ferentiation resulted from autonomous regulation: here we summarize st udies showing that intestinal differentiation is the result of many co mplex cross talks between the different partners forming the intestina l environment. In this review we concentrate on the activity of two of these partners; one is the lymphoid system and the other comprises th e microbiota. We have also analyzed the latest results on the identifi cation and the implications of transcription factors on the induction of intestinal properties with a special focus on the role of the extra cellular matrix on the expression of specific intestinal transcription factors.