Immune responses against HIV-induced cell-derived neoepitopes and HIV control

针对 HIV 诱导的细胞衍生新表位的免疫反应和 HIV 控制

• 批准号: 7736994
• 负责人: Sylvie Le Gall
• 金额: $ 50.81万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7736994
• 关键词: Antigens; Antiviral Agents; Biochemical; Biological Assay; CD4 Positive T Lymphocytes; Cell surface; Cells; Collaborations; Computational Science; Computer Analysis; Cytosol; Cytotoxic T-Lymphocytes; Dendritic Cells; Endoplasmic Reticulum; Epitopes; HIV; HIV Infections; Human Genome; Immune; Immune response; In Vitro; Mass Spectrum Analysis; Mutation; Pattern; Peptide Hydrolases; Peptides; Persons; Process; Production; Property; Proteins; Research; Scanning; Testing; Vaccine Design; Viral; antigen processing; base; cellular targeting; cohort; design; innovation; monocyte; multicatalytic endopeptidase complex; novel; pressure; prevent; programs; response; transmission process

DESCRIPTION (provided by applicant): Current strategies aiming at identifying protective cytotoxic T cell (CTL) responses and designing vaccines against HIV are based on the assumption that immune responses elicited during HIV infection are only directed against HIV epitopes. The limitations of these strategies are the elusiveness of HIV-specific protective immune responses and the fact that many HIV-specific CTL exert pressure on HIV leading to viral mutations and subsequent immune escape. Thus eliciting HIV-specific CTL responses may not be sufficient to block the transmission of HIV. This proposal will specifically test the hypothesis that unconventional HIV-induced host- derived neoepitopes uniquely processed and presented in HIV-infected cells (but not in healthy cells) elicit CTL responses contributing to spontaneous HIV immune control. The identification of these HIV-induced Host- Derived Antiviral Epitopes (HDAE) and corresponding CTL responses -not subjected to immune pressure- will be performed in a unique cohort of HIV spontaneous controllers with weak HIV-specific CTL responses. Cellular and HIV proteins are degraded into epitopes or epitope precursors by the proteasome and other peptidases in the cytosol and then trimmed in the endoplasmic reticulum before being loaded onto MHC-I and displayed at the cell surface for recognition by CTL. 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. In HIV-infected cells, the altered expression and activities of the antigen processing machinery that we recently identified, the presence of an additional HIV-encoded protease along with massive degradation of specific cellular targets are likely to alter the degradation pattern of cellular proteins and produce HDAE. Yet it is impossible to identify HDAE-specific CTL responses by a comprehensive screen of cellular peptides. Through a collaboration with Microsoft Research, we will build a customized prediction program and scan the human genome for antigenic peptides produced in HIV-infected primary cells. With an innovative mass spectrometry- based analysis, we will identify antigenic precursors uniquely found in the cytosol of HIV-infected CD4 T cells from HIV controllers. Their identity will be confirmed through computational analysis and in vitro degradation of target proteins. We will screen HIV-infected persons for CTL responses against HDAE, isolate HDAE-specific CTL and assess their antiviral capacity. We will also assess the capacity of monocyte-derived dendritic cells to cross-present HDAE endogenously processed by HIV-infected CD4 T cells, to stimulate CTL whose antiviral capacity will be assessed. This proposal relies on a cross-disciplinary collaboration involving computational science, novel biochemical and immunological assays designed for primary cells. Identifying HDAE will contribute to the design of novel immunogens eliciting CTL responses that will prevent HIV transmission. The production and presentation of epitopes stimulating efficient immune responses against HIV is key to rational vaccine design. We hypothesize that HIV-induced unconventional degradation of cellular proteins leads to the production of cell-derived novel epitopes contributing to immune control. This project seeks to identify these HIV- induced cell-derived neoepitopes through innovative biochemical and computational approaches and to assess the antiviral capacity of cytotoxic T cells against these neoepitopes.

描述（由申请人提供）：旨在识别保护性细胞毒性T细胞（CTL）反应和针对HIV的疫苗设计的当前策略是基于以下假设：HIV感染期间引起的免疫反应仅针对HIV表现。这些策略的局限性是HIV特异性保护性免疫反应的省力，以及许多HIV特异性CTL对HIV施加压力，导致病毒突变和随后的免疫逃脱。因此，引起HIV特异性CTL反应可能不足以阻止HIV的传播。该提案将特别检验以下假设：在HIV感染的细胞（但不在健康细胞中）中，非常规HIV诱导的宿主诱导的宿主衍生出的新皮质引起的CTL反应有助于自发性HIV免疫控制。这些HIV诱导的宿主诱导的抗病毒表位（HDAE）和相应的CTL反应的鉴定将在唯一的HIV自发控制器中进行，而HIV特异性CTL响应将在独特的HIV自发控制器中进行。细胞和HIV蛋白被蛋白酶体和其他肽酶在细胞质中降解为表位或表位前体，然后在内质网中修剪，然后将其加载到MHC-I上并在MHC-I上加载并在细胞表面显示在细胞表面以识别CTL。在新型表位加工测定的基础上，我们展示了某些HIV表位的优先处理，该特性依赖于我们用来改变无关表位的产生的图案。我们还确定了参与表位加工效率的新因素，即最佳HIV表位的高度可变的细胞内稳定性，这也是由特定基序驱动的。在HIV感染的细胞中，我们最近确定的抗原加工机制的表达和活性改变了，存在额外的HIV编码蛋白酶以及特定细胞靶标的大量降解可能会改变细胞蛋白质的降解模式并产生HDAE。然而，不可能通过细胞肽的全面筛选来鉴定HDAE特异性的CTL响应。通过与Microsoft Research的合作，我们将构建一个定制的预测程序，并扫描人类基因组中为HIV感染的原代细胞产生的抗原肽。通过基于创新的质谱分析，我们将在HIV控制器的HIV感染CD4 T细胞的细胞质中识别出独特的抗原前体。它们的身份将通过计算分析和靶蛋白的体外降解来确认。我们将筛选受HIV感染者的CTL反应，以针对HDAE，分离HDAE特异性CTL并评估其抗病毒能力。我们还将评估单核细胞衍生的树突状细胞对通过HIV感染的CD4 T细胞内源处理的交叉跨性HDAE的能力，以刺激将评估其抗病毒药能力的CTL。该建议依赖于涉及计算科学，新型生化和免疫学测定的跨学科合作。识别HDAE将有助于新型免疫原的设计引起CTL反应，从而防止HIV传播。 刺激对HIV的有效免疫反应的表位的产生和表现是理性疫苗设计的关键。我们假设HIV诱导的细胞蛋白的非常规降解会导致产生有助于免疫控制的细胞来源的新型表位。该项目旨在通过创新的生化和计算方法来鉴定这些艾滋病毒诱导的细胞衍生的新皮特，并评估细胞毒性T细胞针对这些新皮标的抗病毒能力。