TCR signal strength and iNKT cell subset development

项目摘要 不变自然杀伤T细胞(INKT)在多种生物的多种免疫反应中发挥核心作用 从自身免疫、损伤和感染到怀孕和代谢性疾病以及 癌症。INKT细胞的特点是它们使用非常有限的T细胞抗原受体(TCR)谱系来 识别CD1d提呈的脂类抗原，CD1d是一种非多态的主要组织相容性复合体I类 抗原呈递分子。一些功能不同的iNKT细胞亚群，每个亚群都有倾向 运输到不同的组织，并在激活时分泌不同的细胞因子，已经被定义。尽管它是 显然，这些命运分配是在胸腺选择过程中赋予iNKT细胞的， 指导这些决定的环境线索尚不清楚。我们的初步数据显示，1)在野生型 小鼠iNKT TCR的亲和力与iNKT细胞亚群和反映 选择过程中信号的强度；2)具有固定TCR谱系的小鼠iNKT细胞的发育 在不同的遗传背景上影响相似；3)V的使用和CDR3CDR3的序列是各自独一无二的 INKT细胞亚群；4)iNKT细胞发育的最早可定义阶段的信号和基因表达， 在体内天然配体与TCR结合后，TCR降低的小鼠的TCR立即发生改变 发信号。这些小鼠在iNKT细胞亚群的发育过程中也表现出细胞固有的缺陷。基于这些 初步研究，我们假设iNKT细胞的分化和功能是由TCR特异性决定的 和信号强度。这一假设将通过追求以下具体目标来检验：1)确定 胸腺iNKT亚群组成的菌株差异基础；2)确定亲和力和配体的影响- TCR对iNKT细胞亚群发育的特异性。这项提议是创新的，因为它直接 探讨自身配体的TCR特异性/亲和力在确定iNKT细胞亚群的发展中的作用。 这项拟议的研究具有重要意义，因为它将有助于我们理解iNKT细胞亚群的发育 和动力学，这是免疫干预的先决条件，旨在操纵和优化基于iNKT细胞的 治疗。

Project Summary Invariant Natural Killer T (iNKT) cells play a central role in several immune responses in diverse biological contexts ranging from autoimmunity, injury and infections to pregnancy and metabolic disease as well as cancer. iNKT cells are characterized by their use of a very limited T cell antigen receptor (TCR) repertoire to recognize lipid antigens presented by CD1d, a non-polymorphic major histocompatibility complex class I-like antigen-presenting molecule. A number of functionally distinct iNKT cell subpopulations, each with propensity to traffic to different tissues and to secrete different cytokines upon activation, have been defined. Although it is clear that these fate assignments are conferred upon iNKT cells during selection in the thymus, the environmental cues that direct these decisions are unknown. Our preliminary data show that 1) in wildtype mice, the avidity of the iNKT TCR correlates with iNKT cell subsets and the expression of markers reflecting strength of signaling during selection; 2) the development of iNKT cells in mice with a fixed TCR repertoire is affected similarly on different genetic backgrounds; 3) the V usage and CDR3 sequences are unique to each iNKT cell subset; 4) signaling and gene expression in the earliest definable stage of iNKT cell development, immediately after engagement of the TCR by natural ligands in vivo, is altered in mice with reduced TCR signaling. These mice also exhibit a cell intrinsic defect in development of iNKT cell subsets. Based on these preliminary studies, we hypothesize that iNKT cell differentiation and function is determined by TCR specificity and signal strength. This hypothesis will be tested by pursuing the following specific aims: 1) Determine the basis for strain differences in thymic iNKT subset composition; 2) Determine the effect of affinity and ligand- specificity of the TCR on development of iNKT cell subsets. The proposal is innovative because it directly explores the role of TCR specificity/affinity for self-ligands in specifying the development of iNKT cell subsets. The proposed research is significant because it will inform our understanding of iNKT cell subset development and dynamics, a pre-requisite to immune intervention aimed at manipulating and optimizing iNKT cell-based therapies.