Kielian Tammy
Department of Anatomy and Neurobiology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
Front Biosci. 2004 Jan 1;9:732-50. doi: 10.2741/1266.
Microglia are one of the resident mononuclear phagocyte populations within the central nervous system (CNS). These cells share many phenotypical and functional characteristics with macrophages, suggesting that microglia participate in innate immune responses in the brain. As such, microglia are uniquely poised to provide an initial line of defense against invading pathogens into the CNS prior to peripheral leukocyte infiltration. Numerous studies have shown that microglia are capable of producing a wide array of chemokines that act to initiate or promote inflammatory processes in the CNS through facilitating the recruitment of peripheral immune cells into the CNS parenchyma. In addition, microglia also express numerous chemokine receptors that are involved in cell migration and serve as co-receptors for human immunodeficiency virus-1 (HIV-1) infection. The findings obtained from studies of chemokine expression in animal models of CNS infectious diseases as well as from patient populations highlight a marked promiscuity in cerebral chemokine expression patterns with simultaneous expression of multiple chemokines being the general rule. A detailed discussion regarding the profiles and implications of chemokine and chemokine receptor expression in the context of various CNS infectious diseases including HIV-1 encephalitis, other viral encephalitides, bacterial meningitis, and brain abscess is presented. Future studies dissecting the potential roles of individual chemokines and their receptors in the context of CNS infectious diseases may provide insights into the complex regulatory network dictating neuroinflammatory responses.
小胶质细胞是中枢神经系统（CNS）内的常驻单核吞噬细胞群体之一。这些细胞与巨噬细胞具有许多表型和功能特征，表明小胶质细胞参与大脑的固有免疫反应。因此，在周围白细胞浸润之前，小胶质细胞具有独特的能力，能够为抵御病原体侵入中枢神经系统提供第一道防线。大量研究表明，小胶质细胞能够产生多种趋化因子，这些趋化因子通过促进外周免疫细胞向中枢神经系统实质的募集，从而启动或促进中枢神经系统的炎症过程。此外，小胶质细胞还表达多种趋化因子受体，这些受体参与细胞迁移，并作为人类免疫缺陷病毒1型（HIV-1）感染的共受体。从中枢神经系统传染病动物模型以及患者群体中趋化因子表达研究中获得的结果表明，脑趋化因子表达模式存在明显的混杂性，同时表达多种趋化因子是普遍规律。本文详细讨论了趋化因子和趋化因子受体在包括HIV-1脑炎、其他病毒性脑炎、细菌性脑膜炎和脑脓肿在内的各种中枢神经系统传染病中的表达情况及其意义。未来在中枢神经系统传染病背景下剖析单个趋化因子及其受体潜在作用的研究，可能会为支配神经炎症反应的复杂调控网络提供见解。
