The HLA-E peptidome in HIV infection

HIV感染中的HLA-E肽组

• 批准号: 9411277
• 负责人: Sylvie Le Gall
• 金额: $ 25.65万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-14 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9411277
• 关键词: Alleles; Animals; Antigen Presentation Pathway; Antigens; Area; Attenuated; Binding; CD4 Positive T Lymphocytes; CD8-Positive T-Lymphocytes; CD8B1 gene; CD94 Antigen; Cells; Cellular Stress; Collaborations; Computer Analysis; Cytolysis; Cytomegalovirus; Cytotoxic T-Lymphocytes; Epitopes; HIV; HIV Antigens; HIV Genome; HIV Infections; HIV vaccine; HLA-A gene; Haplotypes; Hepatitis C; Hot Spot; Human; Immune; Immune Targeting; Immune Tolerance; Immune response; Individual; Infection; Institutes; KLRD1 gene; Lead; Length; Mass Spectrum Analysis; Mosaicism; Mycobacterium tuberculosis; Natural Killer Cells; Nature; Peptide Signal Sequences; Peptide/MHC Complex; Peptides; Persons; Population; Proteins; Proteome; Reading Frames; Research; Role; SIV; SIV Vaccines; Salmonella; Sampling; Sequence Homology; Surface; T cell response; T-Lymphocyte; Testing; Time; Vaccine Design; Vaccines; Variant; Virus; Walkers; biochemical tools; cell type; cohort; computerized tools; cytotoxicity; density; design; immune clearance; interest; killings; novel; pathogen; receptor; response

Abstract The diversity of HIV sequences and the highly polymorphic nature of MHC-Ia (HLA-A/B/C allomorphs) lead to a highly heterogeneous display of HIV peptides across individuals and create a major obstacle for the design of HIV vaccines. While the diversity of HIV sequences can be overcome through the design of mosaic antigens or immunogens focused on conserved areas of the HIV proteome, the diversity of MHC-Ia is unavoidable. HLA-E is a non-classical MHC-Ib molecule highly conserved among humans (only 2 conserved alleles) that was originally identified for its role in immune tolerance. In 2016 two studies provided the first evidence of cytolytic immune responses against MHC-E-restricted HIV/SIV peptides. They showed broad CD8 T cell immune responses against MHC-E-restricted SIV peptides in a vaccine setting, and cytolytic NK response triggered by one HIV Gag peptide displayed by HLA-E and blocking inhibitory NKG2A receptor (the latter from collaborator Dr Barker and coauthored by the PI). An HLA-E-directed vaccine strategy would be applicable to the population regardless of the MHC-Ia diversity. However HIV peptides displayed by HLA-E in HIV-infected CD4 T cells have not been identified as the only known HIV binder was imputed by sequence homology. This R21 proposal tests the hypothesis that HIV- infected CD4 T cells display a diverse set of HLA-E-restricted HIV peptides targetable by various HLA-E restricted cytolytic immune responses. We developed mass spectrometry approaches and computational tools to identify self- and virus-derived intracellular and MHC-bound peptides from various cell types, including HIV-infected primary CD4 T cells. These HIV peptides include known HIV epitopes, peptides of non-canonical lengths, peptides derived from alternate reading frames of HIV genome, and uncovered novel T cell immune responses. The coverage of the HIV proteome by MHC-peptides in various types of infected cells is uneven, includes common hot spots of nested MHC-bound peptides, which do not correlate with the density of known HIV immune responses. This suggests that the immune responses elicited in natural HIV infection do not fully cover the HIV peptidome displayed by infected cells. Only a direct analysis of HLA-E-bound peptides will identify relevant targets for immune recognition, including peptides generated from alternate reading frames of HIV proteins. Here we propose to 1) define the HLA-E peptidome presented by HIV-infected CD4 T cells, 2) Identify HLA-E- restricted cytolytic immune responses against HIV (including CD8/4 T cells and NK cells). This proposal builds on the PI's expertise in HIV antigen processing and presentation, long-time collaborator Dr Heckerman from Microsoft Research for computational analysis of HLA-E peptides, collaborator Dr Barker for expertise in NK cells, and Dr Walker for CD8 T cells expertise and access to a large cohort of HIV+ donors.

摘要 HIV序列的多样性和MHC-Ia（HLA-A/B/C同种异型物）的高度多态性性质导致了一种新的HIV-1基因。 HIV肽在个体间的高度异质性展示，并为设计 艾滋病毒疫苗。虽然HIV序列的多样性可以通过设计嵌合抗原或嵌合抗原来克服， 由于免疫原集中在HIV蛋白质组的保守区域，MHC-Ia的多样性是不可避免的。HLA-E 是一种在人类中高度保守的非经典MHC-Ib分子（只有2个保守的等位基因）， 最初被鉴定为在免疫耐受中的作用。2016年，两项研究提供了第一个证据， 针对MHC-E限制性HIV/SIV肽的溶细胞免疫应答。他们表现出广泛的CD 8 T细胞 在疫苗环境中针对MHC-E限制性SIV肽的免疫应答和细胞溶解性NK应答 由HLA-E展示的一种HIV Gag肽触发，并阻断抑制性NKG 2A受体（后者来自 Barker博士和PI共同撰写）。 HLA-E导向的疫苗策略将适用于人群，无论MHC-Ia的多样性如何。 然而，在HIV感染的CD 4 T细胞中由HLA-E展示的HIV肽还没有被鉴定为唯一的免疫抑制剂。 已知的HIV结合物通过序列同源性来估算。这项R21提案检验了艾滋病毒- 受感染的CD 4 T细胞显示出多种HLA-E限制的HIV肽， 限制性溶细胞免疫反应。 我们开发了质谱方法和计算工具来识别自身和病毒衍生的 细胞内和MHC结合的肽，包括HIV感染的原代CD 4 T细胞。 这些HIV肽包括已知的HIV表位、非规范长度的肽、衍生自 HIV基因组的交替阅读框架，并发现了新的T细胞免疫反应。的覆盖范围 HIV蛋白质组由MHC-多肽组成，在各类感染细胞中是不均衡的，包括共同的热点区域， 巢状MHC结合肽，其与已知的HIV免疫应答的密度不相关。这 表明在自然HIV感染中引起的免疫应答不完全覆盖HIV肽组 被感染的细胞展示出来。只有HLA-E结合肽的直接分析才能鉴定出相关的靶点， 免疫识别，包括由HIV蛋白的交替阅读框产生的肽。 在这里，我们提出1）定义HIV感染的CD 4 T细胞呈递的HLA-E肽组，2）鉴定HLA-E-T细胞， 针对HIV的限制性溶细胞免疫应答（包括CD 8/4 T细胞和NK细胞）。 该提案建立在PI在HIV抗原加工和呈递方面的专业知识基础上， 来自微软研究院的Heckerman博士进行HLA-E肽的计算分析，合作者Barker博士 NK细胞方面的专业知识，以及步行者博士的CD 8 T细胞专业知识和获得大量HIV+捐赠者的机会。