Investigating the function of self-recognition receptors in tissue-resident natural killer cells

非淋巴器官，如肝脏，含有大量的天然免疫细胞，这些细胞对免疫保护、组织修复和正常的器官生理至关重要。肝脏经常暴露于肠道微生物来源的抗原，因此，维持免疫耐受是该器官中免疫细胞面临的挑战。我的研究计划侧重于了解调节先天免疫细胞功能的机制，并帮助维持非淋巴器官的免疫耐受性。 先天免疫细胞整合来自生殖系编码受体的信号，例如NKR-P1受体家族的成员，以协调复杂的免疫反应。NKR-P1B是该受体家族的抑制性成员，识别基因连锁的C型凝集素相关的ClR-b配体，用于自我/非自我区分。我们已经检测到NKR-P1B在不同器官的固有淋巴样细胞(ILC)亚群上的表达，包括自然杀伤(NK)细胞。驻留在组织中的NK细胞和ILC亚群构成了肝脏中天然免疫细胞的很大比例。了解NKR-P1B：CLR-b识别在这些细胞的生物学中的作用，以及在肝脏免疫和免疫耐受中的作用，是支持非淋巴器官正常免疫细胞功能的基本科学问题。为此，我们提出了以下目标： 1.确定驻肝NK细胞和ILC亚群的精确分子、表型和受体表达谱。 2.确定NKR-P1B的作用：ClRb识别在肝脏滞留的NK细胞和ILC的发育和稳态中的作用。 3.确定NKR-P1B：ClRb识别在肝脏固有免疫细胞功能中的作用。 利用我们的NKR-P1b和ClR-b缺陷小鼠，我们将通过流式细胞仪和共聚焦显微镜技术研究肝脏驻留的NK细胞和ILC群体的受体和配体的表达、组织分布和动态，以确定NKR-P1b：CLR-b识别在肝脏驻留的NK细胞和ILC发展中的作用。我们还将研究NKR-P1B：CLR-b识别在肝脏驻留的NK细胞动态平衡中的作用，它们与肝脏枯否细胞的相互作用，肠道微生物区系对受体表达和功能的影响，以及免疫耐受的维持。最后，我们将研究NKR-P1B：CLR-b识别在调节先天免疫细胞功能中的作用，以及在肝脏中应对病毒攻击的免疫耐受。 这项研究计划，以及拟议的使用我们的基因敲除小鼠的实验，将探索一种独特的、高度保守的免疫受体的功能：组织驻留的先天免疫细胞中的配基对，以回答有关如何促进免疫决策的基本问题，如自我/非我识别和免疫耐受。这项研究将教给我们关于组织驻留的先天免疫细胞生物学的基本教训，并加强我们对免疫细胞的总体理解。

Non-lymphoid organs, such as the liver, harbour a large population of innate immune cells, which are critical for immune protection, tissue repair, and normal organ physiology. The liver is constantly exposed to gut microbiota-derived antigens, therefore, maintaining immune tolerance is a challenge faced by immune cells in this organ. My research program focuses on understanding the mechanisms, which regulate innate immune cell functions, and aid in the maintenance of immune tolerance in non-lymphoid organs. Innate immune cells integrate signals from germ-line encoded receptors, such as members of the NKR-P1 receptor family to orchestrate complex immune responses. NKR-P1B is an inhibitory member of this receptor family, which recognizes genetically-linked C-type lectin-related Clr-b ligand, for self/non-self discrimination. We have detected NKR-P1B expression on subsets of innate lymphoid cells (ILC), including the natural killer (NK) cells, in different organs. Tissue-resident NK cells and ILC subsets make up a large proportion of innate immune cells in the liver. Understanding the role of NKR-P1B:Clr-b recognition on the biology of these cells, as well as, in liver immunity and immune tolerance, represents a basic science question underpinning normal immune cell functions in non-lymphoid organs. To this end, we have proposed the following aims: 1. Determine the precise molecular, phenotypic, and receptor expression profiles of liver-resident NK cell and ILC subsets. 2. Determine the role of NKR-P1B:Clrb recognition in liver-resident NK cell and ILC development and homeostasis. 3. Determine the role of NKR-P1B:Clrb recognition in liver-resident innate immune cell function. Using our NKR-P1B- and Clr-b-deficient mice, we will study receptor and ligand expression, tissue distribution, and dynamics of liver-resident NK cell and ILC populations by flow cytometry and confocal microscopy techniques to determine the role of NKR-P1B:Clr-b recognition in liver-resident NK cell and ILC development. We will also study the role of NKR-P1B:Clr-b recognition in liver-resident NK cell homeostasis, their interactions with liver Kupffer cells, effects of gut microbiota on receptor expression and function, and maintenance of immune tolerance. Finally, we will study the role of NKR-P1B:Clr-b recognition in the regulation of innate immune cell function, and immune tolerance in response to a virus challenge in the liver. This research program, and the proposed experiments using our gene knock-out mice, will explore the function of a unique and highly conserved immune receptor:ligand pair in tissue-resident innate immune cells to answer basic questions on how immune decisions, such as self/non-self recognition and immune tolerance, are facilitated. This study will teach us fundamental lessons about tissue-resident innate immune cell biology, and strengthen our understanding of immune cells in general.