Molecular mechanism of natural killer cell recognition

项目总结 自然杀伤(NK)细胞是先天免疫的主要效应者淋巴细胞，在人类免疫中起着至关重要的作用。 癌症和感染的免疫监测。NK细胞区分健康细胞和异常细胞 一系列激活和抑制受体，识别它们在靶细胞上表达的各自的配体。 NK细胞的识别决定了NK细胞的培养、发育、分化、功能和记忆。 因此，了解NK细胞识别的分子机制在免疫学中具有重要意义。 NK细胞识别具有以下重要特征：(1)它是动态的--NK细胞识别是受支配的 通过活细胞膜上短暂的受体-配体相互作用，(2)它是复杂的-多受体- 配体的相互作用共同决定了NK细胞的反应性，(3)它是特异性的-NK细胞 可以区分健康和异常细胞，(4)是安全的-NK细胞的激活受到严格控制 通过抑制受体避免无意刺激，(5)这是一个结合-信号耦合过程-NK 细胞能够将其结合事件转化为细胞信号，并且(6)它是一个信号整合过程。这 复杂性反映了NK细胞识别的独特要求，这需要同时 检测被测细胞表面的多个配体，精确繁殖 跨细胞膜的识别信号，激活和抑制信号的合理整合，以及精细的 调节NK细胞免疫反应。NK细胞识别的重要性和复杂性促使 深入研究，以了解基本的分子机制。许多车型都已经成为 但调控NK细胞识别的分子机制仍不清楚。中国的主要问题是 大多数研究是无法直接测量受体-配体与单分子的原位相互作用 分辨率，同时在单细胞水平上实时可视化活的NK细胞信号，并全面 确定单个NK细胞的功能表型。在这里，我们提出了一个NK的集成模型 细胞通过整合不同的激活强度和幅度来确定其激活阈值 来自遇到的目标细胞的抑制信号(响应性)，然后调整它以确定未来 在新遭遇时激活的阈值(记忆)。为了检验我们的假设，我们建议应用我们的 最先进的单细胞微吸管分析、单分子和超分辨率成像以及单细胞 测序技术，以直接和精确地测量细胞内表面分子相互作用 单分子水平上单个NK细胞的信号转录组和蛋白质组。这些数据完全可以 阐述NK细胞信号接收、转导、整合和调节的分子机制 承认。这一结果将使我们能够检验我们的假设，并解决免疫学中一个长期存在的问题。 从这项研究中获得的知识将极大地促进我们对NK细胞的了解，并将对 对癌症和感染免疫疗法的发展具有重要意义。

PROJECT SUMMARY Natural killer (NK) cells are the major effector lymphocytes of innate immunity that play a critical role in the immune surveillance of cancer and infection. NK cells distinguish between healthy and abnormal cells by using an array of activating and inhibitory receptors to recognize their respective ligands expressed on a target cell. NK cell recognition determines the education, development, differentiation, function and memory of an NK cell. Thus, understanding the molecular mechanism of NK cell recognition is of critical importance in immunology. NK cell recognition has following important characteristics: (1) it is dynamic – NK cell recognition is governed by the transient receptor-ligand interactions at the live cell membrane, (2) it is complex – multiple receptor- ligand interactions function together to determine the responsiveness of an NK cell, (3) it is specific – NK cells can discriminate between healthy and abnormal cells, (4) it is safe – NK cell activation is stringently controlled by inhibitory receptors to avoid inadvertent stimulation, (5) it is a binding-signaling coupled process – an NK cell is able to translate its binding events to cellular signals, and (6) it is a signaling integration process. This complexity reflects the uniquely demanding nature of NK cell recognition, which requires simultaneous detection of multiple ligands on the surface of the target cell being surveyed, precise propagation of recognition signals across the cell membrane, rational integration of activating and inhibitory signals, and fine- tuning of NK cell immune responses. The importance and complexity of NK cell recognition has motivated intensive research for the understanding of the fundamental molecular mechanism. Many models have been proposed but the molecular mechanism governing NK cell recognition remains elusive. The main problem in most studies is the inability to directly measure in situ receptor-ligand interactions with single-molecule resolution, simultaneously visualize real-time live NK cell signaling at the single-cell level, and comprehensively determine the functional phenotypes of individual NK cells. Here we propose an integration model that an NK cell determines its activation threshold by integrating the strength and amplitude of different activating and inhibitory signals from an encountered target cell (responsiveness) and then adjusts it to determine the future threshold for activation upon a new encounter (memory). To test our hypothesis, we propose to apply our state-of-the-art single-cell micropipette assays, single-molecule and super-resolution imaging, and single-cell sequencing technologies, to directly and precisely measure surface molecular interactions, intracellular signaling, and transcriptome and proteome of single NK cells at the single-molecule level. These data can fully address the molecular mechanism of signal reception, transduction, integration, and regulation of NK cell recognition. The results will allow us to test our hypothesis and settle a long-standing question in immunology. The knowledge gained from this study will greatly advance our understanding of NK cells and will have important implications for the development of immunotherapy against cancer and infection.