The Functions of Migrating Dendritic Cells

肠道的表面积比皮肤大近200倍，并暴露于许多致病微生物。它需要有效的免疫反应来保护它免受感染。另一方面，免疫反应不能针对也存在的无害细菌和食物蛋白质。当它们发生时，这些不适当的反应会产生严重的后果，导致炎症性肠病或食物过敏。为了保证我们的健康，两者之间的平衡？豁免权？然后呢？宽容？维持这种平衡的关键细胞是树突状细胞（DC）。DC在淋巴中持续迁移，将关于肠的信息携带至肠系膜淋巴结（MLN）中的免疫细胞。在到达MLN时，DC与T淋巴细胞相互作用。这种相互作用被认为控制免疫或耐受是否会发生。了解DC如何控制这些过程可能对口服疫苗的设计或预防炎症性肠病非常有益。然而，迁移性DC的研究一直很困难，因为它们不能容易地与MLN中的其他细胞分离。收集肯定是迁移的DC的细胞的唯一方法是通过手术，其用于收集含有DC的淋巴液。以前这种手术只能在大型动物身上进行，我们已经开发出人道的手术技术，从小鼠身上收集迁移的DC，并将它们送回MLN。这将使我们能够首次研究这些细胞及其与T细胞的相互作用，使用仅在小鼠中可用的复杂免疫学技术和资源。我们是目前世界上唯一能够从小鼠淋巴中收集迁移性DC的团队。我们相信，对这些细胞的研究将产生关于免疫反应如何控制的重要信息。

The intestine has a surface area nearly two hundred times greater than the skin, and is exposed to many pathogenic micro-organisms. It requires an effective immune response to protect it from infections. On the other hand, immune responses must not be made against the harmless bacteria and food proteins that are also present. When they occur, these inappropriate responses have serious consequences, leading to inflammatory bowel diseases or food allergies. To ensure our health, the balance between ?immunity? and ?tolerance? must be maintained.A critical cell for maintaining this balance is the dendritic cell (DC). DCs migrate continually, in lymph, carrying information about the intestine to the immune cells in the mesenteric lymph nodes (MLN). On reaching the MLN, DCs interact with T lymphocytes. This interaction is thought to control whether immunity or tolerance will occur. Understanding how DCs control these processes is likely to be highly beneficial in the design of oral vaccines or prevention of inflammatory bowel diseases. However, study of migrating DCs has been difficult because they cannot easily be separated from other cells in the MLNs. The only way to collect cells which are certain to be migrating DCs is by surgery, which is used to collect the DC-containing lymph. Previously this surgery has only been possible in large animals.We have developed humane surgical techniques to collect migrating DCs from mice, and to return them to the MLNs. This will enable us, for the first time, to study these cells and their interactions with T cells, using the sophisticated immunological techniques and resources that are only available in mice. We are currently the only group in the world able to collect migrating DCs from mouse lymph. We believe that the study of these cells will generate important information about how immune responses are controlled.