Role of HIV-1 Env Diversity in Cellular Tropism

描述（由申请人提供）：HIV-1显示出辅助受体使用和宿主细胞库的复杂表型。HIV-1靶向的细胞类型可对疾病进展产生深远影响，提供可促进免疫逃避的不同细胞内环境，调节病毒准种内的变体，并提供潜伏感染的储库。HIV-1变体的巨噬细胞嗜性在进入水平上通过病毒使用和宿主细胞表达辅助受体CCR 5或CXCR 4来调节。辅助受体使用的遗传决定因素映射到HIV- 1 env，特别是Env gp 120中的高变结构域V3。CXCR 4介导的进入对于不同的细胞类型可以是不同的。拟议研究的基本原理是使用CXCR 4的病毒在体内发展，并有助于疾病进展。假设是映射到V3外的Env区域的复杂的、不连续的决定簇以细胞类型依赖性方式调节Env gp 120和CXCR 4之间的相互作用。提出了三个具体目标：1。绘制包膜gp 120 V1-V5区的体内基因型进化图; 2.在不同原代细胞中赋予D-X4表型的gp 120中的图谱决定簇;和3.确定gp 120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，以及纵向的，包括抗逆转录病毒治疗前后来自外周血的病毒以及来自外周血和组织室的病毒。拟议的研究使用创新技术和纵向评估基因型，表型和包膜功能的个人与明确的临床变量，以确定病毒中出现的决定因素在体内发展晚期疾病之前。所提出的研究对于定义使用CXCR 4感染巨噬细胞和胸腺细胞的包膜的独特表型特征、帮助临床医生定义儿童中开始ART的最佳时机的免疫生物标志物、新型趋化因子受体相互作用的细胞类型特异性抑制剂的开发，以及设计具有跨亚型和辅助受体使用的效果的治疗性疫苗，以防止具有扩展的嗜性和致病性的病毒的进化。

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.