FLOW CYTOMETRIC IDENTIFICATION OF A MINORITY POPULATION OF MHC CLASS-II POSITIVE CELLS IN THE NORMAL RAT RETINA DISTINCT FROM CD45(LOW)CD11B C(+)CD4(LOW) PARENCHYMAL MICROGLIA
FLOW CYTOMETRIC IDENTIFICATION OF A MINORITY POPULATION OF MHC CLASS-II POSITIVE CELLS IN THE NORMAL RAT RETINA DISTINCT FROM CD45(LOW)CD11B C(+)CD4(LOW) PARENCHYMAL MICROGLIA
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DOI：
10.1136/bjo.79.9.834
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发表时间：
1995-09-01
影响因子：
4.1
通讯作者：
SEDGWICK, JD
中科院分区：
文献类型：
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作者：
DICK, AD;FORD, AL;SEDGWICK, JD
目的-本研究旨在通过流式细胞术分离和分类正常大鼠视网膜中小胶质细胞的细胞表面表型，以期鉴定视网膜内推定的抗原呈递细胞（APC），这是迄今为止免疫组织化学无法做到的。正常大鼠视网膜小胶质细胞的分离和分类使用一种改进的分离技术，采用梯度Percoll密度梯度细胞分离和如何结果-视网膜小胶质细胞可以通过基于其CD 45（低）CD 11b/c（+）CD 4（低）细胞表面表达的细胞计数来定义。在正常大鼠视网膜中的组成型MHC II类表达几乎完全局限于一个非常小的群体的细胞表达既不低（小胶质细胞），也不高水平的CD 45。三色流式细胞仪分析证实这些MHC II类阳性细胞为ED 2（+）。结论-使用这种敏感的分离技术，我们鉴定了分支的、常驻小胶质细胞的细胞表面特征，并发现它们不组成性表达MHC II类。然而，在表型不同的细胞群体上存在组成型MHC II类表达（CD 45（低/高）ED 2（+））。我们建议这些细胞是对应的血管周围的巨噬细胞中发现的中枢神经系统的抗原外渗的T细胞，虽然他们的确切的视网膜位置只能通过免疫组化分析来确认。实质小胶质细胞作为APC的作用仍不明确。未来使用这种技术分离小胶质细胞和假定的血管周围细胞将有助于确定这些细胞在视网膜内免疫反应的启动和持续中所起的作用。
Aims-This study aimed to isolate and classify by flow cytometry, the cell surface phenotype of microglia in the normal rat retina with a view to identifying putative antigen presenting cells (APC) within the retina, which has to date not been possible by immunohistochemistry.Methods-Normal rat retinal microglia were isolated and classified using a modification of an isolation technique employing graduated Percoll density gradient cell separation and how cytometric phenotypic criteria used for CNS microglia.Results-Retinal microglia can be defined by how cytometry on the basis of their CD45(low)CD11b/c(+)CD4(low) cell surface expression. Constitutive MHC class II expression in the normal rat retina was confined almost exclusively to a very minor population of cells expressing neither low (microglia) nor high levels of CD45. Three colour flow cytometric analysis confirmed that these MHC class II positive cells were ED2(+).Conclusions-Using this sensitive isolation technique we have identified the cell surface characteristics of ramified, resident microglia, and found that they do not constitutively express MHC class II. There is, however, constitutive MHC class II expression on a phenotypically distinct population of cells (CD45(low/high)ED2(+)). We propose these cells are the counterpart of the perivascular macrophages found in the CNS which present antigen to extravasating T cells, although their exact retinal location can only be confirmed by immunohistochemical analysis. The role of parenchymal microglia as APC remains undefined. Future isolation of microglia and putative perivascular cells using this technique will help identify the role these cells play in the initiation and perpetuation of immune responses within the retina.