T cell recognition of the MR1 presented microbial metabolome

项目摘要/摘要 粘膜相关不变T细胞(MAIT)是一种先天的类T细胞亚群，广泛存在于人类中，并得到丰富 在呼吸道里。人类MAIT细胞是由半不变的TcRα链的表达来定义的 TRAV1-2/TRAJ12/20/33及其受MHC相关的非多态MHC类分子的限制 蛋白质1(MR1)。MAIT细胞识别结核分枝杆菌，并可被源自Mtb的小有机分子激活 核黄素生物合成途径。我们已经证明，受MR1限制的T细胞可以使用不受MR1限制的TCR TRAV1-2，并能识别不能产生核黄素的生物(化脓链霉菌)。因此，我们 将MAIT细胞定义为MR1限制性T细胞(MR1T)的子集。此外，我们发现并不是所有的MR1T都可以 基于与已知的MAIT激动剂/MR1配体5-(2-氧代亚丙基氨基)-结合的MR1四聚体- 6-D-核糖胺尿嘧啶(5-OP-RU)，因为它们可以基于它们对MR1的依赖反应来定义 微生物感染和与交替的MR1四聚体结合。我们已经为以下方面生成了管道方法 鉴定新的微生物来源的MR1抗原，并证明肺中的MR1T具有特征 通过寡克隆浓缩，可能是由这些抗原驱动的。总而言之，这些数据支持具体目标 将1)定义由M.smeg/Mtb的MR1提出的配体的谱系，以及 通过MR1定义其演示的结构基础。我们重点研究结核分枝杆菌与其疾病的相关性 人类健康，也来自我们的初步数据显示MR1反应性T细胞迁移到肺 在结核分枝杆菌感染期间。我们的目标2是定义识别抗原的MR1T的T细胞库 由M.smeg/Mtb的MR1提出，并定义了他们识别MR1-的结构基础 抗原复合体。这是来自我们和其他人的初步数据的明显延伸，表明 MR1T种群包含以前未被赏识的多样性。我们试图知道这种多样性是否在 TCR谱系推动了抗原的选择性。与目标1和目标2直接相关的是我们的目标3，它将决定 MR1配体/MR1T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谱系的MR1T细胞选择性地在感染的组织部位扩张 通过MR1对微生物/配体识别的反应。在这里，我们的重点将是MTB，我们将利用 Waltz博士(开普敦)提取肺(BAL)和PBMC样本的专业知识和患者可获得性 感染和控制个体。最终，该项目的工作将支持针对MR1T细胞的 疫苗和免疫疗法作为提高接触结核分枝杆菌后疾病抵抗力的一种手段。

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.