HIV MACROPHAGE TROPISM

描述：巨噬细胞（M）对人类免疫缺陷病毒型至关重要 1（HIV）发病机制。除了它们的抗原呈递功能之外，这些 细胞似乎是HIV感染的重要靶点， 组织中几乎所有的主要HIV毒株都能在M中复制， 嗜巨噬细胞（M-嗜性）病毒株占绝对优势 这些细胞可能与病毒感染有关， 传播，特别是性获得性感染。实质性工作 在过去的十年里，已经完成了定义分子决定因素的工作， M向性这包括将HIV Env V3环鉴定为关键的 用于定义细胞向性的结构域，以及辅助受体的鉴定， 特别是趋化因子受体CCR 5，它是有效进入 M嗜性HIV毒株进入M以及CD 4 +T细胞。尽管有这些令人印象深刻 研究进展，特定的进入机制，利用CD 4和CCR 5（R5）的病毒 菌株）感染M的效率高于使用CD 4和CXCR 4（X4 菌株）。因此，HIV感染的效率可能涉及细胞因子， 除了CD 4和趋化因子受体。在研究期间， 细胞因子可能会影响艾滋病毒的进入，我们发现， 独立产生的针对tetraspan细胞表面蛋白，CD 63， 可以阻止HIV进入M细胞，但不能阻止T细胞。尽管我们对 CD 63，另一种四聚糖蛋白CD 81已被提议作为HCV的受体， 和其它tetraspan蛋白参与信号转导。 值得注意的是，四种独立产生的CD 63特异性单克隆抗体， 抑制M的HIV感染，反对非特异性机制， 封锁因此，CD 63可能在M嗜性中起关键作用。拟议中的小说 针对艾滋病毒进入的抗逆转录病毒疗法。具体目标1。进一步 表征抗CD 63抑制HIV进入M，我们将评估菌株 依赖，以及与此相关的趋化因子受体（CCR 5或CXCR 4）的使用 抑制作用我们将确认CD 63对多个参数的影响， 包括受体表达、构象和支持 融合/感染通过将病毒受体引入细胞背景， 是CD 63缺陷的，然后也引入CD 63。具体目标2。以识别 CD 63介导的HIV进入的机制，包括a）CD 63结合gp 120，CD 4 和CCR 5，B）受体/辅助受体相互作用或共定位，c）对 CD 4周转和d）信号转导。具体目标3。来表征和 定义获得性HIV对抗CD 63抑制的抗性机制。我们将 还评估了抗CD 63抑制与抑制 趋化因子受体结合（AMD 3100用于CXCR 4，以及候选CCR 5 拮抗剂）和病毒融合（T-20），特别是对于具有 对这些进入抑制剂的耐药性。

DESCRIPTION: Macrophages (M) are crucial for human immunodeficiency virus type 1 (HIV) pathogenesis. In addition to their antigen presenting function, these cells appear to be important targets for HIV infection in extravascular tissues. Nearly all primary HIV strains are capable of replication in M, and the overwhelming predominance of macrophage-tropic (M-tropic) virus strains early in disease suggests that these cells may be involved in virus transmission, particularly for sexually acquired infection. Substantial work has been accomplished over the last decade to define molecular determinants of M-tropism. This includes identification of the HIV Env V3 loop as a critical domain for defining cellular tropism, and the identification of coreceptors, particularly the chemokine receptor CCR5, which is required for efficient entry of M-tropic HIV strains into M as well as CD4+T cells. Despite these impressive advances, specific mechanisms of entry, viruses that use CD4 and CCR5 (R5 strains) infect M more efficiently that those using CD4 and CXCR 4 (X4 strains). Efficiency of HIV infection may therefore involve cellular factors in addition to CD4 and chemokine receptors. During studies to identify additional cellular factors that could impact HIV entry, we found that a number of independently generated antibodies to a tetraspan cell surface protein, CD63, could block HIV entry into M, but not T cells. Although little is known about CD63, another tetraspan protein CD81 has been proposed as a receptor for HCV, and other tetraspan proteins have been implicated in signal transduction. Notably, four independently generated monoclonal antibodies specific for CD63 inhibited HIV infection of M, arguing against non-specific mechanisms of blockade. Thus CD63 could play a critical role in M-tropism. The proposed novel anti-retroviral therapies targeting HIV entry. Specific Aim 1. To further characterize anti-CD63 inhibition of HIV entry into M, we will assess strain dependence, and chemokine receptor usage (CCR5 or CXCR4) associated with this inhibition. We will confirm the impact of CD63 on multiple parameters, including receptor expression, conformation, and ability to support fusion/infection by introducing viral receptors into cellular backgrounds that are CD63 deficient, then introducing CD63 as well. Specific Aim 2. To identify mechanisms of CD63-mediated HIV entry, including a) CD63 binding to gp120, CD4 and CCR5, b) receptor/coreceptor interactions or co-localization, c) effects on CD4 turnover and d) signal transduction. Specific Aim 3. To characterize and define mechanisms of acquired HIV resistance to anti-CD63 inhibition. We will also assess potential synergy of anti-CD63 inhibition together with inhibition of chemokine receptor binding (AMD 3100 for CXCR4, as well as candidate CCR5 antagonists) and viral fusion (T-20), particularly for virus strains with resistance to these entry inhibitors.