Role of HIV-1 Env Diversity in Cellular Tropism

描述（由申请人提供）：HIV-1表现出复杂的共受体使用和宿主细胞库表型。HIV-1靶向的细胞类型可以对疾病进展产生深远的影响，提供不同的细胞内环境，促进免疫逃避，调节病毒准种内的变异，并为潜伏感染提供宿主。巨噬细胞对HIV-1变异的嗜性在病毒进入和宿主细胞表达共受体CCR5或CXCR4的水平上受到调节。辅助受体使用的遗传决定因素映射到HIV- 1 env，特别是env gp120中的高变结构域V3。cxcr4介导的进入对于不同的细胞类型是不同的。拟议研究的基本原理是使用cxcr4的病毒在体内发展，并促进疾病进展。假设是，映射到V3外Env区域的复杂的、不连续的决定因素以细胞类型依赖的方式调节Env gp120和CXCR4之间的相互作用。提出了三个具体目标：1。绘制包膜gp120 V1-V5区域的体内基因型进化图谱2. 在不同的原代细胞中定位gp120中赋予D-X4表型的决定因素；和3。确定gp120介导的辅助受体使用对巨噬细胞和胸腺细胞的功能影响。研究是横断面的，包括来自外周血的主要亚型B、A和D病毒，纵向的，包括来自抗逆转录病毒治疗前后的外周血病毒，以及来自外周血和组织隔间的病毒。拟议的研究使用创新技术和纵向评估来自具有明确临床变量的个体的包膜的基因型、表型和功能，以确定在晚期疾病发展之前体内出现的病毒的决定因素。拟议的研究对于定义使用CXCR4感染巨噬细胞和胸腺细胞的包膜的独特表型特征，帮助临床医生确定儿童开始抗逆转录病毒治疗的最佳时间的免疫生物标志物，开发新的，趋化因子受体相互作用的细胞类型特异性抑制剂具有重要意义。设计具有跨亚型和共受体使用作用的治疗性疫苗，以防止具有扩大的向性和发病机制的病毒进化。

DESCRIPTION (provided by applicant): HIV-1 displays complex phenotypes for coreceptor usage and repertoire of host cells. Types of cells targeted by HIV-1 can have a profound impact for disease progression, provide different intracellular milieus that can facilitate evasion of immunity, modulation of variants within the viral quasispecies, and provide reservoirs for latent infection. Macrophage tropism by variants of HIV-1 is regulated at the level of entry by viral use and host cell expression of coreceptors CCR5 or CXCR4. Genetic determinants of coreceptor usage map to HIV- 1 env, in particular hypervariable domain V3 in Env gp120. CXCR4-mediated entry can be distinct for different cell types. The rationale for the proposed studies is that CXCR4-using viruses develop in vivo, and contribute to disease progression. The hypothesis is that complex, discontinuous determinants that map to regions of Env outside V3 modulate interactions between Env gp120 and CXCR4 in a cell-type dependent manner. Three Specific Aims are proposed: 1. Map genotypic evolution in vivo of envelope gp120 V1-V5 regions; 2. Map determinants in gp120 that confer D-X4 phenotype in different primary cells; and 3. Determine functional impact of gp120-mediated coreceptor usage on macrophages and thymocytes. Studies are cross-sectional, including primary subtype B, A, and D viruses from peripheral blood, and longitudinal, including viruses from peripheral blood prior to and following antiretroviral therapy and from peripheral blood and tissue compartments. The proposed studies use innovative technologies and longitudinal evaluation of genotype, phenotype, and function of envelopes from individuals with well-defined clinical variables to identify determinants among viruses that emerge in vivo prior to development of late stage disease. The proposed studies are significant for defining unique phenotypic characteristics of envelopes that use CXCR4 for infection of macrophages and thymocytes, immune biomarkers that aid clinicians in defining the optimal timing for initiation of ART in children, development of novel, cell-type specific inhibitors of chemokine receptor interactions, and designing therapeutic vaccines with effects across subtypes and coreceptor usage to prevent evolution of viruses with expanded tropism and pathogenesis.