van Ewijk W, Brekelmans P J, Jacobs R, Wisse E
Dept. Cell Biology & Genetics, Erasmus University, Rotterdam, The Netherlands.
Scanning Microsc. 1988 Dec;2(4):2129-40.
The three-dimensional architecture of the thymus and mesenteric lymph node reveals several different stromal cell types important in the development and function of T cells. In the thymic cortex, T cells proliferate and differentiate in a meshwork of epithelial-reticular cells. They then migrate towards the medulla where they may interact with interdigitating cells. T cells migrate from the thymus through perivascular spaces, surrounding large vessels at the cortico-medullary boundary. In this area also large thymic cystic cavities are found, their function remains at present unclear. Mature "selected" T cells leave the thymus most probably by the venous bloodstream, to enter peripheral lymph nodes. Upon entering the lymph node they cross the wall of high endothelial venules. On the other hand, lymph enters the node by afferent lymphatics draining into various types of sinuses. Here, macrophages are strategically located to phagocytose and process antigen. These cells then expose antigen to T cells and B cells within the lymph node parenchyma, thus creating a microenvironment for the onset of an immune response. The various microenvironments important in T cell development and T cell function are shown in this paper using scanning electron microscopy as a dissecting tool. We discuss our morphological findings in the light of recent data on the physiology of T cell differentiation and function.
胸腺和肠系膜淋巴结的三维结构揭示了几种对T细胞发育和功能至关重要的不同基质细胞类型。在胸腺皮质中，T细胞在上皮网状细胞的网络中增殖和分化。然后它们向髓质迁移，在那里它们可能与交错突细胞相互作用。T细胞通过血管周围间隙从胸腺迁移，围绕皮质-髓质边界的大血管。在这个区域也发现了大的胸腺囊性腔，其功能目前尚不清楚。成熟的“选择”T细胞很可能通过静脉血流离开胸腺，进入外周淋巴结。进入淋巴结后，它们穿过高内皮微静脉壁。另一方面，淋巴通过引流到各种类型窦的输入淋巴管进入淋巴结。在这里，巨噬细胞位于战略位置以吞噬和处理抗原。然后这些细胞将抗原呈递给淋巴结实质内的T细胞和B细胞，从而为免疫反应的启动创造一个微环境。本文使用扫描电子显微镜作为解剖工具展示了对T细胞发育和T细胞功能重要的各种微环境。我们根据最近关于T细胞分化和功能生理学的数据讨论我们的形态学发现。
