Chodosh J, Nordquist R E, Kennedy R C
Molecular Pathogenesis of Eye Infection Research Center, Dean A. McGee Eye Institute, Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City 73104, USA.
Dev Comp Immunol. 1998 Sep-Dec;22(5-6):621-30. doi: 10.1016/s0145-305x(98)00022-6.
Organized mucosa-associated lymphoid tissue (O-MALT) is defined by mucosal lymphoid follicles with unique overlying lymphoepithelia, and classically appears in tissues with a simple columnar epithelium. Within follicle-associated epithelium, goblet cells are characteristically absent, replaced by ultrastructurally distinct antigen-absorptive cells, termed M cells (or microfold cells) for the appearance of their apical cell membranes. To determine if mammalian conjunctiva, with its stratified squamous epithelium, can be considered as a site of O-MALT, we compared the light and electron microscopic anatomy of conjunctiva from fourteen species of non-human adult mammals, and the conjunctiva of human adults harvested at autopsy. Lymphoid follicles in the conjunctiva were demonstrated in all mammals studied except for mice and rats. In those mammals with conjunctival lymphoid follicles, the follicle-associated conjunctival epithelium was notable for an absence of goblet cells. Transmission electron microscopy demonstrated an intimate association of lymphocytes with surface epithelial cells, but epithelial cell morphology was uniform overlying the follicle, and other ultrastructural features of M cells were absent. Therefore, conjunctival lymphoid follicle-associated stratified squamous epithelium demonstrates some but not all features of O-MALT lymphoepithelia. Further studies are necessary to determine what role conjunctival lymphoid tissue may play in mucosal immunity.
有组织的黏膜相关淋巴组织（O-MALT）由具有独特覆盖淋巴上皮的黏膜淋巴滤泡定义，经典地出现在具有单层柱状上皮的组织中。在滤泡相关上皮内，杯状细胞特征性缺失，取而代之的是超微结构独特的抗原吸收细胞，因其顶端细胞膜的外观而被称为M细胞（或微褶细胞）。为了确定具有复层鳞状上皮的哺乳动物结膜是否可被视为O-MALT的一个部位，我们比较了14种非人类成年哺乳动物结膜以及成人尸检时获取的结膜的光镜和电镜解剖结构。除小鼠和大鼠外，在所有研究的哺乳动物中均发现结膜中有淋巴滤泡。在那些有结膜淋巴滤泡的哺乳动物中，滤泡相关的结膜上皮以缺乏杯状细胞为显著特征。透射电子显微镜显示淋巴细胞与表面上皮细胞紧密相连，但滤泡上方的上皮细胞形态均匀，且不存在M细胞的其他超微结构特征。因此，结膜淋巴滤泡相关的复层鳞状上皮表现出了一些但并非全部的O-MALT淋巴上皮特征。需要进一步研究以确定结膜淋巴组织在黏膜免疫中可能发挥的作用。
