Houston S A, Cerovic V, Thomson C, Brewer J, Mowat A M, Milling S
Centre for Immunobiology, Institute for Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
Mucosal Immunol. 2016 Mar;9(2):468-78. doi: 10.1038/mi.2015.77. Epub 2015 Sep 2.
Dendritic cells (DCs) in the small intestine (SI) and colon are fundamental to direct intestinal immune responses; they migrate to the mesenteric lymph nodes (MLNs) and prime T cells. We demonstrate anatomical segregation of lymphatic drainage from the intestine, specifically that DCs from the SI and colon migrate to different nodes within the MLN, here called the sMLN and cMLN. As a consequence, different frequencies of DC subsets observed in the SI and colon are reflected among the DCs in the sMLN and cMLN. Consistent with the SI's function in absorbing food, fed antigen is presented in the sMLN, but not in the cMLN. Furthermore, the levels of expression of CCR9 and α4β7 are increased on T cells in the sMLN compared with the cMLN. DCs from the cMLN and colon are unable to metabolize vitamin A to retinoic acid (RA); thus, DCs may contribute to the differential expression of tissue homing markers observed in the sMLN and cMLN. In summary, the sMLN and cMLN, and the DCs that migrate to these LNs are anatomically and immunologically separate. This segregation allows immune responses in the SI and colon to be controlled independently.
小肠（SI）和结肠中的树突状细胞（DC）是直接引导肠道免疫反应的基础；它们迁移至肠系膜淋巴结（MLN）并激活T细胞。我们证明了来自肠道的淋巴引流存在解剖学上的分隔，具体而言，来自SI和结肠的DC迁移至MLN内不同的淋巴结，此处分别称为sMLN和cMLN。因此，在SI和结肠中观察到的不同频率的DC亚群反映在sMLN和cMLN中的DC之间。与SI吸收食物的功能一致，喂食抗原呈递于sMLN而非cMLN。此外，与cMLN相比，sMLN中T细胞上CCR9和α4β7的表达水平升高。来自cMLN和结肠的DC无法将维生素A代谢为视黄酸（RA）；因此，DC可能导致了在sMLN和cMLN中观察到的组织归巢标志物的差异表达。总之，sMLN和cMLN以及迁移至这些淋巴结的DC在解剖学和免疫学上是分离的。这种分隔使得SI和结肠中的免疫反应能够独立控制。
