Intestinal M cells: The fallible sentinels?

• 作 者: Harvey Miller Jianbing Zhang R
• 机 构: Institute for Biological Sciences
• 出 处: 世界胃肠病学杂志（英文版）
• 发表日期: 2004年期
• 关键词: M cell Gastrointestinal Development Pathogenesis Mucosal immunity
• 基金项目: the National Institutes of Health USA;National Research Council Canada (A-base) and Dow AgroScience

The gastrointestinal tract represents the largest mucosal membrane surface in the human body. The immune system in the gut is the first line of host defense against mucosal microbial pathogens and it plays a crucial role in maintaining mucosal homeostasis. Membranous or microfold cells, commonly referred to as microfold cells, are specialized epithelial cells of the gut-associated lymphoid tissues (GALT) and they play a sentinel role for the intestinal immune system by delivering luminal antigens through the follicle-associated epithelium to the underlying immune cells. M cells sample and uptake antigens at their apical membrane, encase them in vesicles to transport them to the basolateral membrane of M cells, and from there deliver antigens to the nearby lymphocytes. On the flip side, some intestinal pathogens exploit M cells as their portal of entry to invade the host and cause infections. In this article, we briefly review our current knowledge on the morphology, development, and function of M cells, with an emphasis on their dual role in the pathogenesis of gut infection and in the development of host mucosal immunity.