McMahon Eileen J, Bailey Samantha L, Miller Stephen D
Department of Biology, Westmont College, 955 La Paz Rd, Santa Barbara, CA 93108, United States.
Neurochem Int. 2006 Jul;49(2):195-203. doi: 10.1016/j.neuint.2006.04.004. Epub 2006 May 30.
Dendritic cells (DCs) are a heterogeneous population of migratory cells specialized for the uptake, processing, and presentation of antigen to T cells. They consist of a variety of mature subpopulations, classically divided into "lymphoid" and "myeloid" subsets. Although there likely exists significant plasticity and redundancy between DC subpopulations, unique differences have been noted in their abilities for T cell stimulation, tolerance induction, T helper cell polarization, cytokine secretion, and anatomic localization. Although DCs are conspicuously absent from the healthy CNS parenchyma, their presence in the vascular-rich regions of the healthy CNS has been well established and suggests they may have a role in immune surveillance. DCs do accumulate in the CNS parenchyma in a wide range of inflammatory responses including parasite, viral, or bacterial infection and CNS autoimmune disease. They also are present in CNS immune responses without overt T cell involvement, such as the inflammation accompanying CNS injury or neurodegeneration. Controversy remains on the role of CNS DCs during inflammation and whether they differentiate from CNS-resident microglia or infiltrate from a blood-borne population. This review will summarize DC subsets and function, overview the current research on DCs in the healthy and inflamed CNS, and address discrepancies between experimental studies.
树突状细胞（DCs）是一类异质性的游走细胞群体，专门负责摄取、处理抗原并将其呈递给T细胞。它们由多种成熟亚群组成，传统上分为“淋巴样”和“髓样”亚群。尽管DC亚群之间可能存在显著的可塑性和冗余性，但在它们刺激T细胞、诱导耐受、T辅助细胞极化、细胞因子分泌及解剖定位的能力方面已发现存在独特差异。虽然在健康的中枢神经系统实质中明显不存在DC，但它们在健康中枢神经系统血管丰富区域的存在已得到充分证实，这表明它们可能在免疫监视中发挥作用。在包括寄生虫、病毒或细菌感染以及中枢神经系统自身免疫性疾病在内的多种炎症反应中，DC确实会在中枢神经系统实质中积聚。它们也存在于没有明显T细胞参与的中枢神经系统免疫反应中，例如伴随中枢神经系统损伤或神经退行性变的炎症。关于中枢神经系统DC在炎症过程中的作用以及它们是由中枢神经系统驻留的小胶质细胞分化而来还是从血源性群体浸润而来，仍存在争议。本综述将总结DC亚群及其功能，概述目前关于健康和炎症性中枢神经系统中DC的研究，并探讨实验研究之间的差异。
