MONOCYTE TRAFFIC AND THE NEUROPATHOGENESIS OF AIDS

脑巨噬细胞是中枢神经系统HIV/SIV感染的靶细胞。我们已经证明，血管周围脑巨噬细胞是SIV脑炎(SIVE)动物SIV感染的主要靶点。血管周围巨噬细胞群具有与HIV感染者和痴呆患者血液中循环PBMC相似的免疫表型(CD14/CD16/CD69阳性)。使用CD8耗竭和SIV感染导致SIVE高发生率的模型，我们观察到显著的血管周围巨噬细胞聚集。我们假设，一个独特的、可识别的感染血液单核/巨噬细胞群体，类似于大脑中的血管周围细胞，向中枢神经系统输送，该群体由CD8淋巴细胞控制。为了验证这一假设，我们将：检查SIV感染动物的中枢神经系统，分析病毒血症高峰期和SIVE动物脑巨噬细胞亚群的表型、相对细胞数量和感染水平。这将通过免疫组织化学、共聚焦显微镜下的双标记和三标记免疫荧光以及定量图像分析来检测血管周围脑巨噬细胞CD14/CD16/CD69和gp120的表达。2.确定SIV感染猕猴血液中的单核/巨噬细胞群，其免疫表型与血管周围脑巨噬细胞相对应。我们建议检测外周血单核/巨噬细胞群(CD14)，以了解疾病发展过程中血液和脑中CD14/CD69和CD14/CD16细胞的数量，b)SIV感染水平，以及c)外周血单核/巨噬细胞亚群的env和nef序列与脑和其他组织巨噬细胞的比较。3.检测CD8淋巴细胞对血液和脑内单核/巨噬细胞病毒感染的数量和水平的控制能力。基于对CD8耗竭动物血管周围巨噬细胞快速聚集的观察，我们将研究CD8淋巴细胞通过以下组合来控制感染的单核/巨噬细胞的能力：a)直接裂解，b)间接抑制病毒复制，c)通过体外血脑屏障模型抑制血单核/巨噬细胞运输。

Brain macrophages are targets of HIV/SIV infection in the CNS. We have shown that perivascular brain macrophages are a major target of SIV infection in animals with SIV encephalitis (SIVE). The perivascular macrophage population has a similar immunophenotype to circulating PBMC's observed in the blood of HIV infected humans with dementia (CD14/CD16/CD69 positive). Using a model of CD8 depletion with SIV infection that results in a high incidence of SIVE, we observe significant perivascular macrophage accumulation. We hypothesize that a distinct, identifiable population of infected blood monocyte/macrophages similar to perivascular cell in the brain traffics to the CNS and that this population is held in check by CD8+ lymphocytes. To test this hypothesis we will: Examine the CNS of SIV infected animals with and without CD8 depletion to analyze the phenotype, relative cell numbers, and level of infection of subpopulations of brain macrophages at peak viremia and in animals with SIVE. This will be achieved by using immunohistochemistry, double and triple label immunoflourescence with confocal microscopy and quantitative image analysis to examine the expression of CD14/CD16/CD69 and gp120 by perivascular brain macrophages. 2. Identify populations of monocyte/macrophages in the blood of SIV infected macaques that correspond immunophenotypically to perivascular brain macrophages. We propose to examine populations of peripheral blood monocyte/macrophages (CD14+) for a) the number of CD14/CD69+ and CD14/CD16+ cells in the blood and brain during disease development b) the level of SIV infection, and c) env and nef sequences of peripheral blood monocyte/macrophage subpopulations in comparison to brain and other tissue macrophages. 3. Determine the ability of CD8+ lymphocytes to control the number and level of viral infection of blood and brain monocyte/macrophages. Based on the observation of the rapid accumulation of perivascular macrophages in CD8 depleted animals we will study the ability of CD8+ lymphocytes to keep infected blood monocyte/macrophages in check by combinations of : a) direct lysis b) indirect inhibition of viral replication, and c) inhibition of blood monocyte/macrophage traffic through an in vitro BBB model.