Gebert A, Göke M, Rothkötter H J, Dietrich C F
Abt. Funktionelle und Angewandte Anatomie, Medizinische Hochschule Hannover.
Z Gastroenterol. 2000 Oct;38(10):855-72. doi: 10.1055/s-2000-10001.
The gut-associated lymphoid tissues, e.g., the Peyer's patches and the appendix, constantly internalize antigenic material to rapidly generate an immune response, if necessary. This sampling of antigens is performed by specialized epithelial cells, the "membranous" or "microfold" (M) cells of the dome epithelia. M cells possess a unique ultrastructure and are typically in contact with lymphoid cells. They endocytose macromolecules and particles, including entire microorganisms, at their apical membrane, transport these in vesicles to their basolateral membrane, and exocytose them to the intercellular space. This article reviews the structural and functional characteristics of M cells in the digestive tract in humans and other species. Specializations of M cells for antigen uptake and transport comprise the composition of their apical membrane, a modified cytoskeleton as compared to enterocytes, and a large pocket-like invagination of the basolateral membrane populated by lymphocytes. Besides ultrastructural characteristics, histochemical markers are listed that are available for detecting M cells. The origin and differentiation pathways of M cells and enterocytes of the dome epithelium are outlined and critically commented on. Because M cells are known entry sites of various pathogens and, in the future, might be employed for the oral application of drugs and vaccines, the clinical relevance of M cells in health and disease is discussed.
肠道相关淋巴组织，如派尔集合淋巴结和阑尾，会持续摄取抗原物质，以便在必要时迅速产生免疫反应。这种抗原采样由特化的上皮细胞，即圆顶上皮的“膜性”或“微褶”（M）细胞来执行。M细胞具有独特的超微结构，通常与淋巴细胞接触。它们在顶端膜内吞大分子和颗粒，包括完整的微生物，将这些物质通过囊泡运输到基底外侧膜，然后将其分泌到细胞间隙。本文综述了人类和其他物种消化道中M细胞的结构和功能特征。M细胞用于抗原摄取和运输的特化包括其顶端膜的组成、与肠上皮细胞相比经过修饰的细胞骨架，以及由淋巴细胞填充的基底外侧膜的大口袋状内陷。除了超微结构特征外，还列出了可用于检测M细胞的组织化学标记物。概述并批判性地评论了圆顶上皮M细胞和肠上皮细胞的起源及分化途径。由于M细胞是各种病原体已知的进入位点，并且在未来可能会用于药物和疫苗的口服应用，因此讨论了M细胞在健康和疾病中的临床相关性。
