T cell recognition of the MR1 presented microbial metabolome

项目概要/摘要 粘液相关不变T（MAIT）细胞是一种在人类中普遍存在的先天性T细胞亚群， 在气道里。人MAIT细胞通过表达半恒定TCRα链来定义 TRAV 1 - 2/TRAJ 12/20/33及其受非多态性MHC I类分子、MHC相关 蛋白1（MR 1）。MAIT细胞识别结核分枝杆菌，并可被来自结核分枝杆菌的小有机分子激活。 核黄素生物合成途径。我们已经证明，MR 1限制性T细胞可以使用不受MR 1限制的TCR。 TRAV 1 -2，并能识别生物体（S.化脓菌）不能产生核黄素。因此我们 将MAIT细胞定义为MR 1限制性T细胞（MR 1 T）的子集。此外，我们发现并非所有的MR 1 T都能 基于与已知MAIT激动剂/MR 1配体5-（2-氧代亚丙基氨基）- 6-D-核糖基氨基尿嘧啶（5-OP-RU），因为它们可以基于它们对 微生物感染和与交替的MR 1四聚体结合。我们已经制定了一个管道方法， 鉴定新的微生物来源的MR 1抗原，并证明肺中的MR 1 T的特征在于 通过寡克隆富集，可能由这些抗原驱动。总之，这些数据支持特定的目标 1）定义由来自M的MR 1呈递的配体库。smeg/Mtb和 定义它们由MR 1表示的结构基础。我们专注于结核分枝杆菌的疾病相关性， 而且我们的初步数据表明MR 1反应性T细胞迁移到肺部 在结核病感染期间。我们的目标2是确定MR 1 Ts识别抗原的T细胞库 由来自M的MR 1呈现。smeg/Mtb，并定义其识别MR 1- 抗原复合物这是我们和其他人的初步数据的明显延伸， MR 1 T群体包含以前未被认识到的多样性。我们想知道这种多样性是否 TCR库驱动抗原选择性。与目标1和2直接相关的是我们的目标3，它将决定 MR 1-配体/MR 1 T细胞选择性在人类健康和疾病中的生物学意义。我们 假设具有不同TCR库MR 1 T细胞在感染的组织部位选择性扩增， 通过MR 1对微生物/配体识别的响应。在这里，我们的重点将是结核病，我们利用 Waltz博士（开普敦）的专业知识和患者可及性，从 感染者和对照者。最终，该项目的工作将支持MR 1 T细胞靶向 疫苗和免疫疗法作为一种手段，以提高对疾病的抵抗力暴露于结核分枝杆菌。

Project Summary/Abstract Mucosal associated invariant T (MAIT) cells are an innate-like T cell subset prevalent in humans and enriched in the airway. Human MAIT cells have been defined by the expression of the semi-invariant TCRα chain TRAV1- 2/TRAJ12/20/33 and their restriction by the non-polymorphic MHC class I-like molecule, MHC-related protein 1 (MR1). MAIT cells recognize Mtb and can be activated by small organic molecules, derived from the riboflavin biosynthesis pathway. We have shown that MR1-restricted T cells can use TCRs that are not TRAV1-2, and can recognize organisms (S. pyogenes) that cannot produce riboflavin. Consequently, we define MAIT cells as a subset of MR1-restricted T cells (MR1Ts). Furthermore, we find that not all MR1Ts can be defined based on MR1 tetramer bound to the known MAIT agonist / MR1 ligand 5-(2-oxopropylideneamino)- 6-D- ribitylaminouracil (5-OP-RU), in that they can be defined based on their MR1-dependent response to microbial infection and binding to alternate MR1 tetramers. We have generated a pipeline approach for identifying new, microbially-derived MR1 antigens, and demonstrate that MR1Ts in the lung are characterized by oligoclonal enrichments, possibly driven by these antigens. Together, these data support the specific aims of this grant which are to 1) define the repertoire of ligands presented by MR1 from M. smeg/Mtb and define the structural basis of their presentation by MR1. We focus on Mtb for its disease relevance to human health but also from our preliminary data demonstrating migration of MR1 reactive T cells to the lung during Mtb infection. Our Aim 2 is to define the T cell repertoire of MR1Ts recognizing antigens presented by MR1 from M. smeg/Mtb and define the structural basis of their recognition of the MR1- antigen complex. This is an obvious extension from preliminary data from us and others demonstrating that the MR1T population contains diversity previously unappreciated. We seek to know whether this diversity in the TCR repertoire drives antigen selectivity. Directly related to Aims 1 & 2 is our Aim 3 which will determine the biological significance of MR1-ligand/MR1T cell selectivity in human health and disease. We hypothesize that MR1T cells with a diverse TCR repertoire selectively expand at infected tissue sites in response to microbe/ligand recognition via MR1. Here our focus will be on Mtb, and we capitalize on the expertise and patient accessibility of Dr. Waltz (Capetown) to derive lung (BAL) and PBMC samples from infected and control individuals. Ultimately, the work from this project would support MR1T cell targeted vaccines and immune-therapies as a means to improve resistance to disease following exposure to Mtb.