Ulvestad E, Williams K, Bjerkvig R, Tiekotter K, Antel J, Matre R
Department of Microbiology and Immunology, Gade Institute, University of Bergen, Norway.
J Leukoc Biol. 1994 Dec;56(6):732-40. doi: 10.1002/jlb.56.6.732.
Resting microglia comprise up to 13% of the cells in human central nervous system (CNS) white matter. Their large number and dendritic morphology make them ideally suited to survey the CNS for noxious stimuli. Upon activation microglia gradually lose dendritic processes and transform into typical phagocytic macrophages. Microglia have been implicated as the main antigen presenting cell within the CNS, and appear to be of central importance as effectors and regulators of demyelination. To further characterize the capacity for immune reactivity within the human CNS, we have studied several characteristics of microglia, both in situ and in vitro. We find that human microglia have ultrastructural, phenotypic (CD11c, CD68, acid phosphatase), and functional (FcR and CR mediated phagocytosis) properties typical for cells of the monocyte lineage. Our data indicate that microglia also have properties in common with dendritic antigen-presenting cells. Electron microscopy studies show extended dendritic cell processes on cultured microglia, and microglia are, like dendritic cells, negative for the monocyte markers nonspecific esterase, endogenous peroxidase, CD14, and RFD7. Microglia constitutively express HLA-DR in situ, and express the dendritic cell marker RFD1 upon activation. Coculturing of microglia with CD4+ T cells results in clustering of T cells around microglia and initiation of a mixed lymphocyte reaction, both distinguishing features of dendritic cells. These functional properties of microglia may be of importance for the maintenance of an immunologic response in the CNS, an organ where dendritic cells, in contrast to other organs, have not previously been identified.
静息小胶质细胞占人类中枢神经系统（CNS）白质细胞的比例高达13%。其数量众多且具有树突形态，使其非常适合在中枢神经系统中监测有害刺激。激活后，小胶质细胞逐渐失去树突状突起并转变为典型的吞噬性巨噬细胞。小胶质细胞被认为是中枢神经系统内主要的抗原呈递细胞，并且作为脱髓鞘的效应器和调节因子似乎至关重要。为了进一步表征人类中枢神经系统内的免疫反应能力，我们研究了小胶质细胞在原位和体外的几个特征。我们发现人类小胶质细胞具有单核细胞谱系细胞典型的超微结构、表型（CD11c、CD68、酸性磷酸酶）和功能（FcR和CR介导的吞噬作用）特性。我们的数据表明，小胶质细胞也具有与树突状抗原呈递细胞相同的特性。电子显微镜研究显示培养的小胶质细胞上有延伸的树突状细胞突起，并且小胶质细胞与树突状细胞一样，对单核细胞标志物非特异性酯酶、内源性过氧化物酶、CD14和RFD7呈阴性。小胶质细胞在原位组成性表达HLA - DR，并在激活时表达树突状细胞标志物RFD1。小胶质细胞与CD4 + T细胞共培养会导致T细胞在小胶质细胞周围聚集并引发混合淋巴细胞反应，这两者都是树突状细胞的显著特征。小胶质细胞的这些功能特性可能对维持中枢神经系统中的免疫反应很重要，在这个器官中，与其他器官不同，此前尚未发现树突状细胞。
