Mechanisms and optimization of epitope presentation by HIV-infectable cell subset

项目摘要/摘要 HIV特异性细胞毒性T淋巴细胞(CTL)在控制HIV病毒血症中起着关键作用 自然控制的情况，使他们成为疫苗战略的有吸引力的候选者。然而， 到目前为止，尽管产生了CTL反应，但开发的疫苗未能预防艾滋病毒感染。 针对病毒某些区域的CTL反应在控制艾滋病毒方面可能更有效 比CTL具有其他特异性的复制表明疫苗应该引起选定的CTL反应 与保护相关的。HIV感染细胞对同源表位的有效呈现是至关重要的 保护性CTL反应的条件。然而，令人惊讶的是，人们对细胞内的了解仍然很少。 CD8 T细胞识别的HIV表位的呈递机制。大多数关于艾滋病毒的研究- 特定的CTL功能以合成肽的形式利用同源表位，从而绕过所有细胞内 蛋白质降解的步骤导致表位的呈现。HIV感染几种表达CD4的病毒 将呈现HIV表位的亚群(CD4T细胞、单核/巨噬细胞和树突状细胞)。是否 这些亚集呈现相似的表位，具有相同的动力学尚不清楚。表位呈现的变化 亚群之间的差异可能会影响CTL的抗病毒效果。相反地，识别艾滋病毒有效的区域 在所有亚群中加工成表位对于保护性CTL的鉴定是至关重要的 免疫原的反应和选择。在新的表位处理分析的基础上，我们表现出了优势 一些HIV表位的处理，这是一种依赖于我们用来改变无关的产生的基序的属性 表位。我们还发现了一个与表位处理效率有关的新因素，即高度可变的 最优HIV表位的细胞内稳定性，也是由特定基序驱动的。最后，我们证明了CD4T细胞 比单核细胞的加工活性低，这影响了降解的动力学和抗原性。 由艾滋病毒蛋白质制成的产品。这些数据表明，表位生产受到规则的控制，这些规则可能是 被利用来设计定制的免疫原。具体来说，我们建议：1)确定CTL反应 与艾滋病毒的自发控制相关，病毒血症有效地识别和杀死所有可感染艾滋病毒的细胞亚群。 利用大量的控制者和进步者，我们将评估CD8T的功能 受各种HIV感染亚群刺激的细胞。2)鉴定不同抗原共同产生的多肽 导致自发性可控病毒血症的可感染亚群的处理途径。使用纳米颗粒 为了针对细胞亚群中的HIV蛋白，我们将识别所有亚群产生的抗原肽。3)设计 以及导致选择性呈现保护性HIV表位的测试序列签名。这项建议 依赖于跨学科协作方法，涉及计算科学、生物工程工具和 为原代细胞设计的表位处理和CTL功能的生化和免疫学分析。

Project summary/abstract HIV-specific cytotoxic T-lymphocytes (CTL) play a critical role in containing HIV viremia in acute infection or in situation of spontaneous control, rendering them attractive candidates for vaccine strategies. However vaccines developed so far have failed to protect against HIV infection, this despite generating CTL responses. The fact that CTL responses against certain areas of the virus may be more effective at controlling HIV replication than CTL with other specificities suggests that vaccine should elicit selected CTL responses associated with protection. Effective presentation of the cognate epitopes by HIV-infected cells is a crucial condition for protective CTL responses. However, there is still surprisingly little understanding of intracellular mechanisms governing the presentation of HIV epitopes recognized by CD8 T cells. Most studies on HIV- specific CTL functions utilize cognate epitopes in the form of synthetic peptides, thus bypassing all intracellular steps of protein degradation leading to the presentation of epitopes. HIV infects several CD4-expressing subsets (CD4 T cells, monocyte/macrophages and dendritic cells) that will present HIV epitopes. Whether these subsets present similar epitopes with identical kinetics is unknown. Variations in epitope presentation between subsets may affect the antiviral efficacy of CTL. Conversely identifying areas of HIV that are efficiently processed into epitopes in all subsets is of highest importance for the identification of protective CTL responses and selection of immunogens. Building on novel epitope processing assays, we showed preferential processing of some HIV epitopes, a property that relies on motifs we used to alter the production of irrelevant epitopes. We also identified a novel factor involved in epitope processing efficiency, namely the highly variable intracellular stability of optimal HIV epitopes, also driven by specific motifs. Finally we show that CD4 T cells have lower processing activities than monocytes, which affects the kinetics and antigenicity of degradation products from HIV proteins. These data suggest that epitope production is controlled by rules that could be exploited to design customized immunogens. Specifically we propose to: 1) Determine whether CTL responses associated with spontaneous control of HIV viremia efficiently recognize and kill all HIV-infectable cell subsets. Taking advantage of a large cohort of controllers and progressors, we will assess the functionality of CD8 T cells stimulated by various HIV-infected subsets. 2) Identify peptides commonly produced in distinct antigen processing pathways of infectable subsets contributing to spontaneous controlled viremia. Using nanoparticles to target HIV proteins inside cell subsets, we will identify antigenic peptides produced by all subsets. 3) Design and test sequence signatures leading to the selective presentation of protective HIV epitopes. This proposal relies on a cross-disciplinary collaborative approach involving computational science, bioengineered tools and biochemical and immunological assays of epitope processing and CTL functions designed for primary cells.