Regulation Of Natural Killer Cell Activity

自然杀伤细胞活性的调节

• 批准号: 7196648
• 负责人: Eric O Long
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7196648
• 关键词: MHC class I antigen; allergens; angiogenesis; cell line; confocal scanning microscopy; eosinophil; genetically modified animals; immunogenetics; immunologic receptors; immunoregulation; laboratory mouse; natural killer cells; neurogenesis; receptor expression; respiratory hypersensitivity; site directed mutagenesis; transfection /expression vector

Natural killer (NK) cells are a third subtype of lymphocytes besides B and T cells. NK cells provide an important immune function in the defense against viruses and other intracellular pathogens. Unlike B and T cells, NK cells do not exhibit specificity for antigen. They acquired their name because they can kill cells without prior stimulation by antigen. The killing of normal healthy cells is prevented by inhibitory receptors on NK cells that recognize major histocompatibility class I molecules. A large number of receptors, both activating and inhibitory, that regulate the cytotoxic response of NK cells have been described. In order to evaluate the contribution of individual receptors to the control of NK cell activation, mice defective in a given NK cell inhibitory receptor have been used. In addition, a search for the mouse receptor equivalent to the killer cell immunoglobulin-like receptors (KIR) on human NK cells was undertaken. The mouse inhibitory receptor gp49B is interesting because it is expressed on several cell types that can release granules during activation. Such cells include NK cells, mast cells, and neutrophils. An influx of eosinophils into airway spaces is characteristic of allergic asthma and may contribute to pathogenesis such as airway hyperresponsiveness and remodeling, as well as excessive mucus production. We have shown that infiltration of mouse lungs by eosinophils during allergic inflammation is under negative control by the inhibitory receptor gp49B. gp49B, an Ig-like receptor, is known to negatively regulate mast cells and neutrophils through immuno-receptor tyrosine-based inhibition motifs (ITIM) in its cytoplasmic tail. Using mice deficient in gp49B (gp49B KO), we observed an increase in allergic inflammation in the lungs of Ascaris suum-infected, ragweed (RW) sensitized mice upon RW challenge, as compared to C57BL/6 wild type controls. Expression of gp49B was detected on peripheral eosinophils of control mice and on eosinophils from lungs of animals sensitized and challenged with RW. Furthermore, an increase in conjunctival inflammation, with a predominance of eosinophils, neutrophils, and degranulated mast cells, was observed in RW-sensitized gp49B KO animals that had been challenged in the eye, as compared to C57BL/6 controls. These data provide evidence of a functional inhibitory receptor on eosinophils which has the important protective function of dampening eosinophil-mediated allergic inflammation. A property common to the immune system and the nervous system is regulation by a highly complex and adaptable network of cellular interactions. Major histocompatibility complex (MHC) class I molecules, which are ligands of antigen-specific receptors on CD8 T cells and of inhibitory receptors on NK cells, have an important and surprising role in the control of activity-dependent neuronal plasticity in the central nervous system (CNS). While expression of MHC class I molecules in neurons has been reported, corresponding immune receptors have not been identified in the central nervous system. We have shown that a killer cell imunoglobulin-like receptor (KIR) gene is selectively expressed in subregions of the mouse brain where synaptic plasticity and neurogenesis occur, including olfactory bulbs, rostral migratory stream, and dentate gyrus of hippocampus. These results suggest new functions for KIR in the CNS. Uterine tissue in early human pregnancy is characterized by extensive vascular remodeling, invasion of fetal trophoblast cells, and by an abundance of maternal natural killer (NK) cells. Trophoblast cells express membrane-bound and soluble isoforms of the non-classical major histocompatibility class I molecule HLA-G. How NK-trophoblast cell interactions influence vascular remodeling is unknown. We have shown that interferon-gamma secretion by resting NK cells is induced by soluble, but not solid-phase antibodies to the killer cell immunoglobulin-like receptor (KIR) 2DL4, a receptor for HLA-G. KIR2DL4 is constitutively internalized into Rab5-positive compartments by a dynamin-dependent process. Soluble HLA-G was endocytosed into KIR2DL4-containing compartments in NK cells and in 293T cells transfected with KIR2DL4, as shown by confocal microscopy. The profile of genes upregulated by KIR2DL4 engagement on resting NK cells suggests a role in vascularization. IL-8 secretion was induced by transfection of KIR2DL4 into 293T cells, and occurred only with recombinant forms of KIR2DL4 that trafficked to endosomes. We propose that soluble HLA-G produced by fetal trophoblast cells activates maternal NK cells through endocytosis of KIR2DL4, thereby promoting vascularization during implantation.

自然杀伤（NK）细胞是B和T细胞以外的淋巴细胞的第三个亚型。 NK细胞在防御病毒和其他细胞内病原体的防御方面具有重要的免疫功能。与B和T细胞不同，NK细胞对抗原没有特异性。他们之所以获得名称，是因为他们可以在没有抗原刺激的情况下杀死细胞。识别主要组织相容性I类分子的NK细胞上的抑制受体可以预防正常健康细胞的杀戮。已经描述了调节NK细胞细胞毒性反应的大量受体。为了评估单个受体对控制NK细胞活化的贡献，已经使用了给定NK细胞抑制受体中缺陷的小鼠。此外，还进行了与人类NK细胞上的杀伤细胞免疫球蛋白样受体（KIR）相等的小鼠受体的搜索。 小鼠抑制受体GP49B很有趣，因为它在激活过程中可以释放颗粒的几种细胞类型表达。这些细胞包括NK细胞，肥大细胞和中性粒细胞。将嗜酸性粒细胞涌入气道空间是过敏性哮喘的特征，可能有助于发病机理，例如气道高反应性和重塑，以及过量的粘液产生。我们已经表明，在过敏性炎症过程中，嗜酸性粒细胞浸润小鼠肺部受抑制受体GP49B的阴性对照。已知GP49b是一种类似Ig的受体，它通过其细胞质尾巴中的免疫受体酪氨酸抑制基序（ITIM）对肥大细胞和中性粒细胞负调节。使用缺乏GP49B（GP49B KO）的小鼠，我们观察到与C57BL/6野生类型控制相比，在RW挑战时，在RW挑战时，Ascaris Suum感染的Ragweed（RW）敏化小鼠的肺中有过敏性炎症增加。在对照小鼠的周围嗜酸性粒细胞以及来自RW敏感和挑战的动物的肺嗜酸性粒细胞上检测到GP49b的表达。此外，与C57BL/6对照组相比，在RW敏感的GP49B KO动物中观察到了嗜酸性粒细胞，中性粒细胞和脱粒的肥大细胞的结膜炎症的增加，在RW敏感的GP49B KO动物中观察到了受到挑战的RW GP49B KO动物。这些数据提供了嗜酸性粒细胞上功能性抑制受体的证据，这些受体具有抑制嗜酸性粒细胞介导的过敏性炎症的重要保护功能。 免疫系统和神经系统常见的特性是通过高度复杂且适应性的细胞相互作用网络来调节的。主要的组织相容性复合物（MHC）I类分子是CD8 T细胞上抗原特异性受体的配体和NK细胞上抑制性受体的配体，在控制中枢神经系统（CNS）的活性依赖性神经元可塑性方面具有重要而令人惊讶的作用。尽管已经报道了MHC I类分子在神经元中的表达，但在中枢神经系统中尚未鉴定出相应的免疫受体。我们已经表明，在小鼠大脑的子区域中选择性表达了一个杀手细胞的抗肿瘤蛋白样受体（KIR）基因，其中突触可塑性和神经发生发生，包括嗅球，鼻子迁移流，以及海马的齿状回。这些结果表明了CNS中KIR的新功能。 早期妊娠的子宫组织的特征是广泛的血管重塑，胎儿滋养细胞细胞的侵袭以及大量的母体天然杀手（NK）细胞。滋养细胞表达膜结合的膜结合和可溶性同工型，I类分子HLA-G类。 NK-Trophophast细胞相互作用如何影响血管重塑。我们已经表明，静息NK细胞的干扰素 - γ分泌是可溶性的，但不是对杀手细胞免疫球蛋白样受体（KIR）2DL4的固体相抗体，这是HLA-G的受体。 KiR2DL4通过依赖性依赖性过程组成型将RAB5阳性隔室化为RAB5阳性隔室。如共聚焦显微镜所示，将可溶性HLA-G内吞成NK细胞中的KIR2DL4隔室和用KIR2DL4转染的293T细胞中的可溶性HLA-G。 KIR2DL4参与对静息NK细胞上调的基因的谱图表明在血管形成中起作用。通过将KIR2DL4转染到293T细胞中，诱导了IL-8分泌，并且仅以被运送到内体的重组形式的KiR2DL4发生。我们提出，由胎儿滋养细胞细胞产生的可溶性HLA-G通过KIR2DL4的内吞作用激活母体NK细胞，从而在植入过程中促进血管化。