INTERACTIONS OF HUMAN IMMUNODEFICIENCY VIRUS WITH THE CD4 RECEPTOR

人类免疫缺陷病毒与 CD4 受体的相互作用

• 批准号: 6098959
• 负责人: Edward Berger
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6098959
• 关键词: CD4 molecule; HIV envelope protein; T lymphocyte; cell type; cofactor; complementary DNA; cytokine receptors; genetic strain; host organism interaction; human immunodeficiency virus 1; laboratory mouse; laboratory rabbit; macrophage; membrane fusion; tissue /cell culture; virus infection mechanism

During the past year, this laboratory continued studies on the mechanism of HIV entry and tropism, as well as development of therapeutic and protective strategies based on the molecules involved in entry. 1) Expansion of the coreceptor repertoire. Initially, we identified CXCR4 and CCR5 as major coreceptors. We have since shown that amongst diverse primary HIV-1 isolates, usage of these coreceptors correlates closely with tropism for T-cell lines vs. primary macrophages. We also found that many primary strains use CCR3, as well as the orphan receptor STRL33. Coreceptor activity has also been observed for CCR8; since CCR8 is abundantly expressed in thymus but not in peripheral T cells or macrophages, we are exploring the possibility that HIV might adapt to use this coreceptor when replicating in the thymus. We also demonstrated that another orphan is a receptor for fractalkine, the first member of the CX3C family of chemokines; CX3CR1 was found to have coreceptor activity for diverse HIV-1 strains. In the HL60 model for eosinophil differention, we demonstrated different modes of regulation for CCR3 and CCR1. 2) Molecular mechanism of fusion. We have expanded on our earlier demonstration that soluble CD4 activates Env to fuse with cells expressing coreceptor but not CD4. We have shown that soluble CD4 exposes new neutralization epitopes involved in coreceptor interaction. These findings have implications for new HIV vaccine strategies. We have also initiated efforts to define minimal regions of Env essential for interaction with coreceptors, as well as to define critical regions of the coreceptors, with particular emphasis on the importance of transmembrane regions. 3) Therapeutic strategies based on molecules involved in fusion. We analyzed a battery of compounds identified by the Division of AIDS as HIV inhibitors that act at an early step in the replication cycle. Several of these were found to be potent inhibitors of Env-mediated fusion. Each acted with comparable efficiency with different coreceptors; the molecular site of action of these inhibitors is an important question for their potential use as anti-HIV drugs or topical transmission-blocking agents. We also demonstrated fusion inhibition by synthetic peptides representing certain transmembrane regions of CXCR4 and CCR5. Finally we characterized a single-chain immunotoxin made with a monoclonal antibody having broad cross-reactivity against diverse HIV-1 strains; the immunotoxin showed selective cytotoxicity against HIV Env-expressing cells, with potency greater than that of CD4-Pseudomonas exotoxin. We are pursuing the possible utility of Env-targeted toxins for eliminating reservoirs of HIV-infected cells from people undergoing highly active antiretroviral therapy.

在过去的一年中，该实验室继续 研究艾滋病毒进入和潮流的机制以及 基于 参与进入的分子。 1）肌感受器的扩展 曲目。最初，我们将CXCR4和CCR5确定为主要 受体受体。从那以后，我们已经表明，在各种初选中 HIV-1分离株，这些共感受器的使用与 T细胞线与原发性巨噬细胞的热带主义。我们还发现 许多主要菌株使用CCR3以及孤儿受体 strl33。还观察到CCR8的共感受器活性。 由于CCR8在胸腺中大量表达，但在周围不表达 T细胞或巨噬细胞，我们正在探索HIV的可能性 在胸腺中复制时，可能会适应使用该共肽。 我们还证明了另一个孤儿是 Fractalkine，CX3C趋化因子家族的第一个成员； 发现CX3CR1具有多种HIV-1的共肽活性 菌株。在嗜酸性粒细胞差异的HL60模型中，我们 证明了CCR3和CCR1的不同调节模式。 2）融合的分子机制。我们已经扩展了 早期的演示可溶性CD4激活Env与 表达共肽的细胞，但不表达CD4。我们已经表明 可溶性CD4暴露了涉及的新的中和表位 共感受器的相互作用。这些发现对新的影响 艾滋病毒疫苗策略。我们还开始努力定义 Env与共感受器相互作用必不可少的Env的最小区域 以及定义cocecector的关键区域，特别是 强调跨膜区域的重要性。 3） 基于融合的分子的治疗策略。我们 分析了由艾滋病划分鉴定的一系列化合物 作为在复制周期早期起作用的艾滋病毒抑制剂。 发现其中一些是Env介导的有效抑制剂 融合。每种都以可比的效率作用，不同 受体受体；这些抑制剂的分子作用部位是 重要的问题是它们可能用作抗HIV药物或 局部传输阻滞剂。我们还展示了融合 由代表某些跨膜的合成肽抑制 CXCR4和CCR5区域。最后，我们描述了一个 用单克隆抗体制成的单链免疫毒素 针对不同的HIV-1菌株的广泛交叉反应；这 免疫毒素对HIV的选择性细胞毒性 表达环境的细胞，其效力大于 CD4妊娠毒素。我们正在追求 靶向的毒素，用于消除感染HIV感染细胞的储层 来自接受高度活跃的抗逆转录病毒疗法的人。