HIV-1 INFECTION IN HUMAN FETAL BRAIN CELL CULTURES & PEDIATRIC AIDS BRAIN TISSUE

解释HIV-1如何导致儿童大脑损伤的机制 一直专注于其他的解释;要么HIV-1可以诱导毒素 从感染的巨噬细胞和/或导致低水平感染，在选择 神经胶质细胞群。 我们建立了一个有用的HIV-1模型 感染人类胎儿脑细胞培养来解决这个问题。 通过用病毒体感染或用前病毒DNA转染， 不表达HIV-1的CD 4受体的人胎儿星形胶质细胞， 迅速发展为非细胞病变但具有生产性的感染， 会逐渐减弱为持续性感染 病毒基因组的持久性 在宿主染色体中保持整合状态， 在RNA或蛋白质水平表达。 然而，HIV-1可以被激活， 由CD 4+人淋巴细胞提供的因子。 细胞因子TNF-α和 II-1 β也能够激活潜伏的HIV-1基因组， 转染，再次进展为生产性但有限的感染。 已知从人单核细胞诱导HIV-1的其他细胞因子， GM-CSF、II-6、II-2和干扰素不能激活星形胶质细胞中的HIV-1。 这些细胞因子特异性的进一步证据来自于 使用转染到星形细胞中的HIV-1 LTR CAT载体进行实验。 CAT活性在用TNF-α和II-1 β处理的细胞中最高 即使在没有病毒反式激活因子达特蛋白的情况下。 在24 向持续感染的星形胶质细胞添加细胞因子（HIV-1 mRNA）的小时数 对于Nef、达特和Rev蛋白，可以鉴定。 NEF成绩单 似乎是最丰富的HIV-1转录本。 脑检查 12例儿童AIDS患者的组织中也发现了星形胶质细胞、GFAP 染色，4例中与HIV-1放射性标记探针杂交呈阳性 例 在其中几个部分中，没有HIV-1的证据 抗原p24和gp 41。 这些结果表明，星形胶质细胞可能 携带一种未表达的HIV-1前病毒DNA，可以在 大脑通过细胞因子。 据报道，TNF-α和II-1 β是 存在于艾滋病患者的脑组织中 进一步研究 HIV-1基因转录调控的分子机制及其对人类免疫缺陷病毒（HIV-1）基因表达的影响 目前，儿科艾滋病脑病的临床相关性 中求进工作总

Mechanisms that explain how HIV-1 causes damage in the pediatric brain have focused on alternative explanations; either HIV-1 can induce toxins from infected macrophages and/or cause a low level infection in select populations of glial cells. We have established a useful model of HIV-1 infection in human fetal brain cell cultures to address this question. Through either infection with virions or transfection with proviral DNA, human fetal astrocytes, which do not express the CD4 receptor for HIV-1, quickly develop a non-cytopathic but productive infection which gradually diminishes to a persistent infection. Persistence of the viral genome is maintained in an integrated state in the host chromosome without expression at the RNA or protein levels. However, HIV-1 can be activated by factors provided by CD4 + human lymphocytes. Cytokines TNF-alpha and II-1 beta are also able to activate the latent HIV-1 genome following transfection, to again progress into a productive but limited infection. Other cytokines known to induce HIV-1 from human monocyte cells such as GM-CSF, II-6,II-2, and interferon do not activate HIV-1 from astrocyte. Further evidence of the specificity of these cytokines comes from experiments using an HIV-1 LTR CAT vector transfected into astroctyes. CAT activity is highest in cells treated with TNF-alpha and II-1 beta even in the absence of the viral transactivator, tat protein. Within 24 hrs of cytokine addition to persistently infected astrocytes, HIV-1 mRNAs for nef, tat, and rev proteins can be identified. The nef transcript appears to be the most abundant HIV-1 transcript. Examination of brain tissues from 12 pediatric AIDS cases also revealed astrocytes, GFAP staining, with positive hybridization to HIV-1 radiolabeled probes in 4 cases. In several of these sections, there was no evidence for HIV-1 antigens, p24 and gp 41. These results suggest that astrocytes may harbor an unexpressed HIV-1 proviral DNA that can be activated in the brain through cytokines. TNF-alpha and II-1 beta are reported to be present in AIDS brain tissue in high concentrations. Further study of the molecular mechanism of transcriptional control of HIV-1 and its clinical correlates in pediatric AIDS encephalopathy are currently in progress.