Structural correlates of T cell receptor signaling

T 细胞受体信号传导的结构相关性

• 批准号: 8773573
• 负责人: Kenan Christopher GARCIA
• 金额: $ 45.18万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-12-01 至 2018-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8773573
• 关键词: Address; Affinity; Agonist; Antigens; Autoantigens; Autoimmune Diseases; Autoimmune Process; Autoimmunity; Binding; Bioinformatics; Biophysics; Blood; CD4 Positive T Lymphocytes; Cellular biology; Communicable Diseases; Complement; Complex; Coupled; Coupling; Development; Discrimination; Disease; Docking; Engineering; Exhibits; Geometry; HIV; HLA-DR15; HLA-DR4 Antigen; Health; Human; Image; Immune; Immune System Diseases; Immune system; Immunity; Immunology; Immunotherapeutic agent; Individual; Interleukin-2; Left; Libraries; Ligands; Literature; Logic; Malignant Neoplasms; Mediating; Memory; Methodology; Molecular; Molecular Mimicry; Multiple Sclerosis; Mus; Natural Immunity; Pathogenesis; Patients; Peptide Library; Peptide Signal Sequences; Peptide/MHC Complex; Peptides; Peripheral; Pharmaceutical Preparations; Phenotype; Play; Property; Protein Engineering; Proteome; Receptor Signaling; Relative (related person); Role; Sampling; Sequence Analysis; Series; Signal Transduction; Structure; System; T memory cell; T-Cell Receptor; T-Lymphocyte; TNFRSF10A gene; Testing; Time; Translating; Yeasts; base; biophysical properties; cross reactivity; deep sequencing; design; in vivo; insight; interfacial; microbial; pathogen; prevent; protein aminoacid sequence; response; tool

DESCRIPTION (provided by applicant): The ability of T cells to engage functionally distinct ligands throughout development and peripheral surveillance has been attributed to TCR cross-reactivity. Yet, it is still unclear to what extent TCRs really are cross-reactive, or how cross-reactivity impacts signaling. These questions are important to understanding the mechanisms for, and consequences of, TCR ligand discrimination in normal and pathogenic immunity. Here we wish to apply a powerful methodology, peptide-MHC yeast display coupled with deep sequencing, to explore the interplay between TCR cross-reactivity, structure, and function by asking: 1-How cross-reactive are TCRs? Our peptide-MHC libraries enable, for the first time, an experimental determination of TCR/pMHC cross-reactivity that can gauge the extent of cross-reactivity between different TCRs to a common pMHC, autoimmune TCRs, and TCRs isolated from different types of T cells. 2-Do TCR/pMHC cross-reactivity and binding topology play instructive roles in TCR signaling? Most 'alternative' agonist peptides characterized in the literature are simply cognate ligands with conservative substitutions that are recognized in similar structural modes by a TCR, leading to the common assumption that TCR signaling is structurally indiscriminate. In contrast, we found that a non-homologous peptide discovered by pMHC yeast display was recognized with high affinity by a TCR in an unusual docking geometry that failed to activate intracellular signaling. This was the first demonstration that the docking mode of the TCR/pMHC complex is an important variable in TCR signaling. We wish to identify peptides that are recognized by several TCRs in diverse structural modes, and ask how the biophysical parameters of TCR cross-reactivity modulate downstream signaling in mouse and human systems where state-of-the-art tools exist to interrogate mechanism. 3-Do TCR/pMHC cross-reactivity and docking geometry influence human autoimmune disease? TCR cross-reactivity, molecular mimicry, and several aberrant structural features of self-antigen recognition have been proposed to play roles in development of autoimmune disease. Indeed, several MBP-reactive TCRs derived from patients with Multiple Sclerosis assume a very unusual binding mode with MBP presented by HLA-DR15. We wish to test these hypotheses by probing the cross-reactive properties of MBP-reactive human TCRs, and identifying peptides that are recognized in different binding modes than the MBP autoantigen. 4-What is the molecular basis of non- signaling TCR/pMHC interactions in natural human immunity? Unexpectedly, we recently found that a high percentage of T cell clones isolated from human blood using HIV-DR4 tetramers do not signal in response to these peptide antigens, apparently engaged in 'non-productive', but specific, TCR/pMHC interactions in vivo. We wish to determine the structural basis for how TCR binding is decoupled from signaling by these peptides, and isolate cognate endogenous agonist peptides. Collectively, we propose to both interrogate and manipulate basic aspects of TCR cross-reactivity in a manner that is directly germane to human translational immunology.

描述(由申请人提供)：T细胞在整个发育和外周监视过程中与不同功能配体结合的能力被归因于TCR交叉反应。然而，目前仍不清楚TCR在多大程度上确实存在交叉反应，或者交叉反应如何影响信号传递。这些问题对于理解正常免疫和致病免疫中TCR配体歧视的机制和后果是重要的。在这里，我们希望应用一种强大的方法，肽-MHC酵母展示结合深度测序，通过以下问题来探索TCR交叉反应、结构和功能之间的相互作用：1-TCR的交叉反应如何？我们的多肽-MHC文库首次实现了TCR/pMHC交叉反应的实验测定，可以测量不同TCR与共同的pMHC、自身免疫性TCR和从不同类型T细胞分离的TCR之间的交叉反应程度。2-TCR/pMHC交叉反应和结合拓扑在TCR信号转导中起指导作用吗？文献中描述的大多数“替代”激动肽都是具有保守取代基的简单同源配体，TCR以相似的结构模式识别这些配体，导致人们普遍认为TCR信号在结构上是不分青红皂白的。相反，我们发现pMHC酵母展示发现的一种非同源多肽被TCR以高亲和力识别，该TCR处于不寻常的对接几何结构，无法激活细胞内信号。这是第一次证明TCR/pMHC复合体的对接模式是TCR信号中的一个重要变量。我们希望识别被不同结构模式的TCR识别的多肽，并询问TCR交叉反应的生物物理参数如何调节小鼠和人类系统中的下游信号，在这些系统中，存在最先进的工具来询问机制。3-TCR/pMHC交叉反应和对接几何形状是否影响人类自身免疫性疾病？TCR交叉反应、分子模拟和自身抗原识别的几个异常结构特征 已被提出在自身免疫性疾病的发展中发挥作用。事实上，来自多发性硬化症患者的几个MBP反应性TCR呈现出一种非常不寻常的结合模式，与由HLA-DR15呈现的MBP结合。我们希望通过探索MBP反应的人TCR的交叉反应特性来检验这些假设，并识别以不同于MBP自身抗原的结合模式识别的多肽。4-TCR/pMHC在自然免疫中非信号相互作用的分子基础是什么？出乎意料的是，我们最近发现，使用HIV-DR4四聚体从人血中分离出的高比例T细胞克隆不会对这些多肽抗原产生信号，显然参与了体内的TCR/pMHC相互作用，这种相互作用是非生产性的，但具有特异性。我们希望确定TCR结合如何与这些肽的信号解偶联的结构基础，并分离同源内源性激动肽。总的来说，我们建议以一种与人类翻译免疫学直接相关的方式来询问和操纵TCR交叉反应的基本方面。