Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
Innate Immun. 2010 Dec;16(6):391-404. doi: 10.1177/1753425909357577. Epub 2010 Jan 18.
From the moment we are born, we are exposed to a vast variety of microbes. The intestine in particular is perhaps inhabited by the largest number of microbes, consisting of both established commensals as well as sporadic pathogens. Mucosal surfaces form an important barrier against microbial invasion. Together with the physical barrier that they provide, mucosal surfaces also rely on innate immune functions to sense luminal microbes and signal accordingly to generate protective immune responses. However, since innate immune recognition is microbial specific and antigen-independent, the contact with both beneficial commensals and harmful pathogens creates the need for discrimination between the two. The mechanisms governing the ability of the mucosal immune system to discriminate between commensals and pathogens have long been unclear; however, recent discoveries have shed some light on this distinction. This review will summarize the current theories put forth to explain how the mucosal immune system maintains tolerance towards commensals while retaining the ability to mount inflammatory responses against pathogens.
从我们出生的那一刻起，我们就接触到了各种各样的微生物。特别是肠道，可能居住着数量最多的微生物，包括已建立的共生菌以及偶发的病原体。黏膜表面是抵御微生物入侵的重要屏障。黏膜表面除了提供物理屏障外，还依赖于先天免疫功能来感知腔微生物，并相应地发出信号，产生保护性免疫反应。然而，由于先天免疫识别具有微生物特异性和抗原非依赖性，因此与有益共生菌和有害病原体的接触都需要对两者进行区分。长期以来，黏膜免疫系统区分共生菌和病原体的能力的机制一直不清楚；然而，最近的发现为这一区别提供了一些线索。这篇综述将总结目前提出的解释黏膜免疫系统如何在对共生菌保持耐受的同时保留对病原体产生炎症反应的能力的理论。
