IMMUNOPHENOTYPIC DIVERSITY OF BRAIN MACROPHAGES: IMPLICATIONS FOR NEUROAIDS

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。人类感染艾滋病毒或猕猴感染SIV通常会导致脑炎(蜂窝或SIVE)，其特征是巨噬细胞和多核巨细胞在血管周围聚集，其中许多是生产性感染。据推测，SIVE/HIVE的发展与循环中单核细胞进入大脑的迁移(和滞留)增加有关。这些单核细胞进入大脑将促进神经侵袭，并为感染提供额外的细胞。由于缺乏能够很容易地区分血管周围巨噬细胞、最近迁移的单核细胞和实质小胶质细胞的特定标记物，对这种胚泡发育的直接评估一直受挫。近年来，CD14和CD45的表达以及CD11b的表达被用来区分实质小胶质细胞(CD11b+CD14和CD45)和血管周围巨噬细胞(CD11b+CD14+CD45+)，并将后者定义为中枢神经系统感染的主要细胞类型。然而，很明显，共享CD11b、CD14和CD45表达的SIV感染细胞群是异质性的。这表明我们可能正在研究几个细胞群体，包括那些最近从血液中迁入的细胞。为了进一步评估这一点，并试图确定其他脑巨噬细胞群体的免疫表型，包括那些最近进入中枢神经系统的细胞，我们对各种细胞标记物进行了多标记共聚焦显微镜检查，并结合SIV的原位杂交(ISH)。所用标记物包括CD11b、CD14、CD45、髓系组织细胞抗原(克隆MAC387)、髓系相关蛋白8(MRP8)和14(MRP14)、CD68、HAM56、LN5和CD163。未被SIV感染的MAC387+、MRP8+、MRP14+细胞的存在可能代表最近招募的单核/巨噬细胞或抵抗感染的巨噬细胞群。最后，CD163似乎标记激活的小胶质细胞，因为在正常动物中没有看到实质细胞的标记，而在脑炎动物中有广泛的标记。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Infection of humans with HIV or macaques with SIV often leads to an encephalitis (HIVE or SIVE) characterized by perivascular accumulations of macrophages and multinucleated giant cells, many of which are productively infected. It is assumed that the development of SIVE/HIVE is associated with increased migration (and retention) of circulating monocytes into the brain. The immigration of these monocytes into the brain would facilitate neuroinvasion and provide additional cells for infection. Direct assessment of this hypyothesis has been frustrated by the lack of specific markers that can easily differentiate among perivascular macrophages, recently immigrated monocytes, and parenchymal microglia. Recently, expression of CD14 and CD45 in conjunction with CD11b has been used to differentiate parenchymal microglia (CD11b+ CD14¿CD45¿) from perivascular macrophages (CD11b+ CD14+CD45+) and define the latter as the primary cell type productively infected in the CNS. It was clear, however, that the population of SIV-infected cells that shared expression of CD11b, CD14 and CD45 was heterogeneous. This suggested that we might be looking at several populations of cells including those that had recently immigrated from the blood. To assess this further and try to define the immunophenotypes of additional populations of brain macrophages, including those that had recently entered the CNS, we performed multilabel confocal microscopy for a variety of cell markers combined with in situ hybridzation (ISH) for SIV. The markers used included CD11b, CD14, CD45, myeloid histocyte antigen (clone MAC387), myeloid related proteins 8 (MRP8) and 14 (MRP14), CD68, HAM56, LN5 and CD163. The presence of MAC387+, MRP8+, MRP14+ cells not infected by SIV could represent either recently recruited monocyte/macrophages or a population of macrophages resistant to infection. Lastly, CD163 appears to label ¿activated¿ microglia as no labeling of parenchymal cells was seen in normal animals, while in animals with encephalitis there labeling was extensive.