Williams M B, Butcher E C
Department of Pathology, and the Digestive Disease Center, Stanford University School of Medicine, CA 94305, USA.
J Immunol. 1997 Aug 15;159(4):1746-52.
The specificity and efficiency of extravasation of subsets of memory and naive lymphocytes into organized lymphoid tissues has been the subject of recent controversy, but has not been directly assessed in physiologic systems. Here, we compare the lymphoid organ homing of naive and phenotypically defined memory T cells, focusing on memory subsets differentially expressing the integrin receptor alpha4beta7, which is implicated in homing to mucosal sites. Naive T cells (CD44(low), Thy1+) home to all secondary lymphoid organs. Alpha4beta7(high) memory-phenotype (CD44(high)) T cells home to Peyer's patches as efficiently as naive lymphocytes, whereas alpha4beta7- memory-phenotype T cells are essentially excluded from entry into these mucosal lymphoid organs. In contrast, alpha4beta7- memory-phenotype cells home approximately twice as efficiently as alpha4beta7(high) T cells to peripheral lymph nodes, but only approximately 20% as well as naive T cells. Interestingly, the spleen recruits all three identified subsets with nearly equal efficiency. The relative subset localization is similar 2.5 h after injection and after overnight trafficking, suggesting that memory cells can directly extravasate from blood into Peyer's Patches and lymph nodes. We conclude that subsets of memory T cells defined by patterns of homing receptor expression display differential homing to organized lymphoid tissues, an ability that may facilitate homeostatic interactions and target contributions to specialized regional immune responses.
记忆性淋巴细胞和初始淋巴细胞亚群向有组织的淋巴组织外渗的特异性和效率一直是近期争论的焦点，但尚未在生理系统中得到直接评估。在此，我们比较了初始T细胞和表型定义的记忆性T细胞的淋巴器官归巢情况，重点关注差异表达整合素受体α4β7的记忆亚群，该受体与归巢至黏膜部位有关。初始T细胞（CD44低表达、Thy1+）归巢至所有二级淋巴器官。α4β7高表达记忆表型（CD44高表达）的T细胞向派尔集合淋巴结归巢的效率与初始淋巴细胞相同，而α4β7低表达记忆表型的T细胞基本上被排除进入这些黏膜淋巴器官。相反，α4β7低表达记忆表型的细胞向外周淋巴结归巢的效率约为α4β7高表达T细胞的两倍，但仅约为初始T细胞的20%。有趣的是，脾脏以几乎相同的效率募集所有三个已鉴定的亚群。注射后2.5小时以及过夜迁移后，相对亚群定位相似，这表明记忆细胞可以直接从血液外渗至派尔集合淋巴结和淋巴结。我们得出结论，由归巢受体表达模式定义的记忆性T细胞亚群对有组织的淋巴组织表现出不同的归巢能力，这种能力可能有助于稳态相互作用以及对特定区域免疫反应的靶向贡献。
