The internal surfaces of the human body are covered by distinct types of epithelial cells and mucus-secreting cells. The mucosal surfaces serve many vital functions, such as respiration (nasal passage and lung), absorption (gastrointestinal tract), excretion (lung, urinary tract, large intestine), and reproduction (reproductive tract). In performing these functions, the host is inevitably exposed to environmental antigens, food particles, commensal flora, and pathogens. Mucosal surfaces contain specialized dendritic cells (DCs) capable of sensing these external stimuli and mounting appropriate local responses depending on the nature of the elements they encounter. In the absence of pathogens, mucosal DCs either ignore the antigen or induce regulatory responses. Upon recognition of microorganisms that invade the mucosal barrier, mucosal DCs mount robust protective immunity. This review highlights progress in our understanding of how mucosal DCs process external information and direct appropriate responses by mobilizing various cells of the innate and adaptive immune systems to achieve homeostasis and protection.

中文翻译：

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粘膜树突状细胞。

人体的内表面被不同类型的上皮细胞和粘液分泌细胞所覆盖。粘膜表面具有许多重要功能，例如呼吸（鼻腔和肺），吸收（胃肠道），排泄（肺，泌尿道，大肠）和生殖（生殖道）。在执行这些功能时，宿主不可避免地要暴露于环境抗原，食物颗粒，共生菌群和病原体。粘膜表面包含专门的树突状细胞（DC），它们能够感知这些外部刺激并根据其遇到的元素的性质进行适当的局部反应。在没有病原体的情况下，粘膜DC会忽略抗原或诱导调节反应。在识别到侵入粘膜屏障的微生物后，粘膜DC具有强大的保护免疫力。这篇综述突出了我们对粘膜DC如何处理外部信息并通过动员先天性和适应性免疫系统的各种细胞以实现体内平衡和保护的直接反应的理解的进展。