Structure of the intestinal flora responsible for development of the gut immune system in a rodent model

The intestinal flora comprising indigenous, autochthonous bacteria is const antly present in the alimentary tract of host animals, including humans. Th e indigenous bacteria greatly affect the structure and functions of the int estinal mucosa. Studies involving gnotobiotic mice or rats have shown that the presence of limited kinds of intestinal bacteria is responsible for the development of the gut immune system, such as secretory IgA, major histoco mpatibility complex molecules and intraepithelial lymphocytes. Understandin g of the structure of the intestinal flora or the organization of the micro bial population in the intestine, based on evaluation of the immunological responses, may clarify its functions in the host animal. (C) 2000 Editions scientifiques et medicales Elsevier SAS.