树突细胞（DC）是已知功能最强大的专职抗原呈递细胞（APC），能高效摄取、加工并呈递抗原给T细胞，同时上调表达主要组织相容性复合物（MHC）Ⅰ、Ⅱ类分子，协同刺激分子和黏附分子，为T细胞激活提供协同刺激信号，从而启动适应性免疫应答。近年来对DC表面标记的研究揭示了更为细致的DC亚群分类，也推动了不同亚群DC生物学功能的研究进展。DC启动免疫应答具有双重作用，一方面能促进适应性免疫应答的激活，清除病原体；另一方面又能诱导调节性T细胞的产生，导致免疫耐受。DC在启动保护性免疫反应的同时，还可能因捕获、传递入侵的病毒而促进某些病毒感染。DC因其复杂的生物学功能而成为研究免疫应答反应的热点。本文主要对上述内容的研究进展做一简要综述。

Dendritic cells (DCs) are known as the most powerful professional antigen-presenting cells (APCs). DCs could efficiently uptake, process and present antigens to T cells. During this process, DCs upregulate major histocompatibility complex (MHC) typeⅠand type Ⅱ molecules, costimulatory molecules and adhesion molecules, providing costimulatory signal to T cell activation, in order to trigger the adaptive immune response. In recent years, studies of the DC surface markers revealed a more detailed classification of DC subsets, which also contributed to research progress of the biological function of different DC subsets of DCs. DCs have dual role in the initiation of immune response. On the one hand, DCs can promote the activation of adaptive immune response to clear pathogens; on the other hand, DCs can induce immune tolerance through induction of regulatory T cells. In addition, DCs may also facilitate the virus infection by capturing some virus particles and transporting to their target cells. The functional complexity makes DCs become a research hotspot of immune response. In this paper, recent research progression related to the above fields is reviewed.