Role of HIV-1 Env Diversity in Cellular Tropism

描述(由申请人提供)：HIV-1显示共受体用途和宿主细胞谱系的复杂表型。HIV-1靶向的细胞类型可以对疾病的发展产生深远的影响，提供不同的细胞内环境，有助于逃避免疫，调节病毒准种内的变异，并为潜在感染提供蓄水池。HIV-1变异体的巨噬细胞趋向性在进入水平上受病毒使用和宿主细胞表达辅助受体CCR5或CXCR4的调节。共受体使用的遗传决定因素映射到HIV-1环境，特别是环境gp120中的高变区V3。CXCR4介导的进入对于不同的细胞类型可能是不同的。这项拟议研究的基本原理是，使用CXCR4的病毒在体内发展，并有助于疾病的进展。假设是复杂的、不连续的决定因素映射到V3外的Env区域，以细胞类型依赖的方式调节Env gp120和CXCR4之间的相互作用。我们提出了三个具体的目标：1.定位gp120包膜V1-V5区的基因进化；2.定位不同原代细胞中决定D-X4表型的gp120决定因素；3.确定gp120介导的辅受体使用对巨噬细胞和胸腺细胞的功能影响。研究是横向的，包括来自外周血的主要B、A和D亚型病毒，以及纵向的，包括来自抗逆转录病毒治疗前后以及来自外周血和组织间的病毒。拟议的研究使用创新技术和对来自具有明确临床变量的个体的包膜的基因型、表型和功能的纵向评估，以确定在晚期疾病发展之前体内出现的病毒的决定因素。这项拟议的研究对于确定使用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启动ART的最佳时机的免疫生物标记物、开发新型的、细胞类型的趋化因子受体相互作用的特异性抑制剂以及设计跨亚型和辅助受体使用的治疗性疫苗以防止具有扩大的趋向性和致病机制的病毒的进化具有重要意义。

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.