NKT细胞在动脉粥样硬化中的作用

然杀伤T细胞（natural killer T cell,NKT细胞）是一种特殊的淋巴细胞亚群,具有部分T细胞和NK细胞的特征。与这些细胞不同的是,NKT细胞不仅能够识别醣脂类抗原,还在激活后产生促炎症因子和抗炎症因子。由于这些特性,NKT细胞在炎症和免疫方面的研究越来越热。动脉粥样硬化是一种受免疫调节的炎性疾病,因此对NKT细胞在该疾病中作用的研究也逐渐开展起来。     

NKT 细胞在动脉粥样硬化中的作用*

然杀伤T细胞(natural killer T cell,NKT细胞)是一种特殊的淋巴细胞亚群,具有部分T细胞和NK细胞的特征。与这些细胞不同的是,NKT细胞不仅能够识别醣脂类抗原,还在激活后产生促炎症因子和抗炎症因子。由于这些特性,NKT细胞在炎症和免疫方面的研究越来越热。动脉粥样硬化是一种受免疫调节的炎性疾病,因此对NKT细胞在该疾病中作用的研究也逐渐开展起来。     

NKT细胞在抗肿瘤免疫中的作用及其机制

NKT细胞是免疫细胞中一类具有NK细胞特定标志的T细胞亚群,经活化,既可直接作为抗肿瘤效应细胞发挥杀伤作用,又能通过激活其他免疫效应细胞,如NK细胞,间接实现抗肿瘤作用。NKT细胞在抗肿瘤免疫、获得性免疫应答及免疫调节中起着重要作用。     

鱼类自然杀伤样细胞的研究进展

哺乳类自然杀伤(Natural killer,NK)细胞是先天性免疫系统的重要效应细胞,因其非特异的细胞毒杀伤作用而得名,NK细胞可介导先天性免疫应答和获得性免疫应答。与哺乳动物类似的是,在鱼类中也发现与NK细胞功能相似的细胞毒细胞,称为NK样(NK-like)细胞。NK样细胞也具有细胞毒作用,是鱼类抗病毒、细菌、寄生虫感     

恒定自然杀伤T细胞与肿瘤免疫治疗北大核心CSCD

恒定自然杀伤T细胞(i NKT)是T淋巴细胞的一个独特亚群,兼具自然杀伤(NK)细胞和T细胞特征,同时表达T细胞受体(TCR)和NK细胞表面标志。i NKT细胞被激活后,通过分泌细胞因子,活化其它免疫细胞参与先天性免疫和获得性免疫,在抗肿瘤免疫过程中发挥调节作用。在多种癌症患者体内,发现外周血中i NKT细胞的数量降低、功能减弱,进而导致临床治疗效果不佳。近年来,基础研究和早期临床试验结果表明,注射抗原递呈细胞或/和体外培养并活化的i NKT细胞,抗肿瘤免疫治疗效果显著。本文就i NKT细胞的分类及生物学特性,在肿瘤免疫治疗中的作用与其机制,以及其临床应用等进行综述。     

T细胞肿瘤免疫治疗的研究进展

随着科学技术的不断发展,人类对肿瘤疾病认识的不断深入,也带来了医学界对肿瘤治疗模式的改变。通过现代生物技术调节机体的免疫功能状态,利用人体自身免疫系统来治疗肿瘤疾病,并取得了很大的成效。肿瘤免疫治疗成为继手术、化疗和放疗之后的第四种有效治疗肿瘤的方法。用于肿瘤免疫治疗的细胞主要有:T淋巴细胞(T lymphocyte)、树突细胞(dendritic cell,DC)、自然杀伤细胞(natural killer cell,NK cell)、细胞因子诱导的杀伤细胞(cytokine-induced killer cell,CIK cell)以及DC-CIK细胞(dendritic cell-cytokine-induced killer cell)。在肿瘤的发生和发展过程中,T细胞介导的细胞免疫发挥着重要的作用。因此,探索T细胞肿瘤免疫治疗一直是肿瘤免疫研究领域的研究热点,现就T细胞相关的肿瘤免疫疗法研究进展作一综述。     

自然杀伤T细胞的研究进展

自然杀伤T细胞(NKT)是一类具有NK受体和T细胞受体且显示NK细胞和T细胞两方面性质的淋巴细胞.因其表型和功能与T细胞,B细胞和NK细胞等免疫细胞有所不同,近年来颇受关注.NKT细胞具有高度保守的TCR表型(TCRVα24/β11-人),同时共表达NK细胞特有标志CD161.NKT细胞识别由CD1d分子提呈的特异糖脂分子,并能够分泌大量细胞因子,参与机体的先天性免疫和获得性免疫反应.研究发现,NKT细胞在抗感染,抗肿瘤,以及抑制自身免疫性疾病(如:肥胖型糖尿病,再生障碍性贫血等)的发生中发挥着重要作用.本文将对有关NKT细胞特征和功能的研究现状,以及存在的问题作一综述.     

肿瘤免疫治疗中NK细胞的激活策略及研究进展

NK细胞(natural killer cell)是机体固有免疫系统中一类重要的淋巴样细胞,在免疫调节中发挥重要作用。NK细胞MHCⅠ非限制性杀伤肿瘤细胞的特性受到人们广泛关注。然而肿瘤组织浸润难、杀伤活性弱、免疫监视功能低的缺陷极大限制了NK细胞的活性。因此,本文总结了肿瘤免疫治疗中NK细胞激活的机制,探讨了NK细胞在肿瘤免疫治疗中的激活策略,综述了近年来激活NK细胞用于肿瘤免疫治疗的研究进展,以期为利用NK细胞提高肿瘤免疫治疗效果提供新思路。     

自然杀伤T细胞抗感染作用的研究进展

自然杀伤T细胞(NKT细胞)是一类与自然杀伤细胞具有共同表面标记的T细胞,可识别由CD1d呈递的糖脂类抗原。活化后的NKT细胞通过分泌多种细胞因子和趋化因子,增强树突细胞(DC)、T细胞、B细胞等多种免疫细胞的功能,在非特异与特异性免疫之间起桥梁作用。近年来研究发现,NKT细胞不仅在抗细菌感染中发挥重要作用,在抗病毒及抗寄生虫感染中也发挥一定作用。     

MiR-150缺失增强小鼠NKT细胞IFN-γ产生并抑制黑色素瘤细胞的肺转移

CD1d限制性NKT细胞(自然杀伤T细胞)是一群具有免疫调节功能的T细胞亚群,在调控多种免疫应答中发挥重要作用．MicroRNAs介导的RNA干扰已被证明是调控NKT细胞发育和功能的关键分子机制,然而特异microRNA在NKT细胞发育和功能中的作用目前仍不清楚．在本研究中,我们采用miR-150基因敲除小鼠以及流式细胞术、ELISA等方法,观察miR-150对小鼠NKT细胞发育和功能的影响．结果表明：miR-150基因缺失致小鼠胸腺NKT细胞数量减少,但不影响外周NKT细胞的数量;活化后miR-150敲除小鼠NKT细胞与野生型小鼠NKT细胞相比,IFN-γ产生增加．进一步采用小鼠黑色素瘤模型观察miR-150对肿瘤细胞转移的影响,发现miR-150敲除显著增强半乳糖神经鞘氨醇(α-Galcer)对小鼠黑色素瘤细胞肺转移的抑制效果．上述结果为特异microRNA调控NKT细胞发育和功能的研究提供了新的线索．     

Interleukin-10 suppresses natural killer cell but not natural killer T cell activation during bacterial infection

Interleukin (IL)-10 is an anti-inflammatory cytokine known to modulate the outcome of sepsis by decreasing pro-inflammatory cytokine production, including IL-12, a main activator of natural killer (NK) cells. We hypothesized that neutralization of IL-10 would increase NK and natural killer T (NKT) cell activation through increased IL-12 in a mouse model of bacterial peritonitis. NK and NKT cell activations were measured by CD69 expression on NK1.1+/CD3- and NK1.1+/CD3+ cells after cecal ligation and puncture (CLP). NK cells were significantly more activated in mice treated with anti-IL-10 antibodies, whereas no such effect was observed in NKT cells. Similarly, intracellular interferon gamma (IFN-gamma) levels were increased in NK cells of anti-IL-10-treated mice, but not in NKT cells. IL-12 and IL-18 levels were increased in both CLP groups, but in anti-IL-10-treated mice, early IL-12 and late IL-18 levels were significantly higher than in controls. Survival at 18 h after CLP was lower in anti-IL-10 mice, which was associated with increased liver neutrophil accumulation. In summary, these data show an activating effect of IL-10 on NK, but not on NKT cells after CLP, which corresponded with decreased survival, higher IFN-gamma production, and increased remote organ neutrophil accumulation. These effects were not mediated by IL-12 and IL-18 alone, and reinforce a role for NK cells in remote organ dysfunction following peritonitis.     

Evaluation of natural killer cell activity

Natural killer (NK) cells are being appreciated not only for their ability to recognize and lyse tumor cells and virus-infected cells but also for their immunoregulatory properties. NK cells provide a first line of defense against invading pathogens with a two pronged attack, lysis of infected cells and secretion of cytokines and chemokines with potent antipathogen effects. This article describes the standard chromium release assay, which measures the ability of NK cells derived from the peripheral blood to lyse appropriate target cells.     

自然杀伤细胞受体的研究进展

自然杀伤细胞（ＮＫ细胞）可表达两类功能相悖的识别受体,即活化受体（ＫＡＲ）和抑制受体（ＫＩＲ）。ＫＩＲ能识别自身细胞上的ＭＨＣⅠ类分子与自身或外来肽形成２的复合物,所产生的抑制信号可阴断ＫＡＲ的活化,以此抑制ＮＫ细胞的细胞毒作用。如果靶细胞失去ＫＩＲ所识别的配体,ＮＫ细胞即可通过ＫＡＲ对靶细胞进行攻击。本文将介绍此类受体的结构及基识别与信号转导机制的研究进展。     

Avian influenza virus directly infects human natural killer cells and inhibits cell activity

Natural killer (NK) cell is a key component of innate immunity and plays an important role in host defense against virus infection by directly destroying infected cells. Influenza is a respiratory disease transmitted in the early phase of virus infection. Evasion of host innate immunity including NK cells is critical for the virus to expand and establish a successful acute infection. Previously, we showed that human influenza H1N1 virus infects NK cells and induces cell apoptosis, as well as inhibits NK cell activity. In this study, we further demonstrated that avian influenza virus also directly targeted NK cells as an immunoevasion strategy. The avian virus infected human NK cells and induced cell apoptosis. In addition, avian influenza virion and HA protein inhibited NK cell cytotoxicity. This novel strategy has obvious advantages for avian influenza virus, allowing the virus sufficient time to expand and subsequent spread before the onset of the specific immune response. Our findings provide an important clue for the immunopathogenesis of avian influenza, and also suggest that direct targeting NK cells may be a common strategy used by both human and avian influenza viruses to evade NK cell immunity.

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Dok1 and Dok2 proteins regulate natural killer cell development and function

Natural killer (NK) cells are involved in immune responses against tumors and microbes. NK‐cell activation is regulated by intrinsic and extrinsic mechanisms that ensure NK tolerance and efficacy. Here, we show that the cytoplasmic signaling molecules Dok1 and Dok2 are tyrosine phosphorylated upon NK‐cell activation. Overexpression of Dok proteins in human NK cells reduces cell activation induced by NK‐cell‐activating receptors. Dok1 and Dok2 gene ablation in mice induces an NK‐cell maturation defect and leads to increased IFN‐γ production induced by activating receptors. Taken together, these results reveal that Dok1 and Dok2 proteins are involved in an intrinsic negative feedback loop downstream of NK‐cell‐activating receptors in mouse and human.     

Enhancement of natural killer cell cytotoxicity by using static magnetic field to increase their viability

Natural killer (NK) cells are innately immune to the body’s immune system and can actively recognize and kill cancer cells. This study explores the potential for enhancing the killing ability of NK cells by co-culturing the NK cells with the target cells under a static magnetic field (SMF). In this study, NK92-MI cell lines were cultured in the presence of a 0.4-T SMF. The effect of the SMF on NK cell viability was evaluated by means of an MTT assay. Culturing tests were performed with inhibitors of the DAG/IP3, STAT3, ERK, JNK and p38 pathways in order to examine the possible signaling cascade responsible for the SMF effect on the NK92-MI cell viability. Finally, the effect of the SMF on the cytotoxicity of the NK92-MI cells was evaluated by co-culturing the NK cells with K562 leukemia cell lines. The results showed that the application of a 0.4-T SMF significantly increased (p < 0.05) the viability of the NK92-MI cells. Furthermore, the inhibitor tests indicated that the SMF affected cell viability by activating multiple MAPK signaling pathways (ERKs, JNKs, and p38-MAPK). Finally, SMF pre-exposure for 48 hr significantly improved the killing activity of the NK92-MI cells (p < 0.05). That is, pre-exposure to SMF increased the viability of the NK92-MI cells and improved their killing ability against K562 tumor cells. In general, the present results suggest that NK cells pre-exposed to 0.4-T SMF show potential as a tool for immune-therapy treatment of cancer.     

母胎界面自然杀伤细胞的研究进展

自然杀伤(natural killer,NK)细胞是母胎界面丰度最高的免疫细胞,在妊娠早期的子宫蜕膜中大量积聚。研究表明母胎界面NK细胞具有独特表型和功能,在妊娠期免疫耐受调节、子宫内膜蜕膜化、滋养细胞侵袭、子宫螺旋动脉重塑、胎盘形成和胎儿生长、发育等多方面都发挥关键作用,但是其在妊娠中的功能及其作用机制还有待深入研究。本综述总结了近年来母胎界面NK细胞的功能以及它们在妊娠相关疾病中作用的研究进展,旨在对母胎界面NK细胞功能有更全面的了解,并为妊娠相关疾病的诊治提供新的思路。     

Unravelling natural killer cell function: triggering and inhibitory human NK receptors

Natural killer (NK) cells represent a highly specialized lymphoid population characterized by a potent cytolytic activity against tumor or virally infected cells. Their function is finely regulated by a series of inhibitory or activating receptors. The inhibitory receptors, specific for major histocompatibility complex (MHC) class I molecules, allow NK cells to discriminate between normal cells and cells that have lost the expression of MHC class I (e.g., tumor cells). The major receptors responsible for NK cell triggering are NKp46, NKp30, NKp44 and NKG2D. The NK-mediated lysis of tumor cells involves several such receptors, while killing of dendritic cells involves only NKp30. The target-cell ligands recognized by some receptors have been identified, but those to which major receptors bind are not yet known. Nevertheless, functional data suggest that they are primarily expressed on cells upon activation, proliferation or tumor transformation. Thus, the ability of NK cells to lyse target cells requires both the lack of surface MHC class I molecules and the expression of appropriate ligands that trigger NK receptors.     

Natural killer and natural killer T cells in liver fibrosis

The liver lymphocyte population is enriched with natural killer (NK) cells, which play a key role in host defense against viral infection and tumor transformation. Recent evidence from animal models suggests that NK cells also play an important role in inhibiting liver fibrosis by selectively killing early or senescence activated hepatic stellate cells (HSCs) and by producing the anti-fibrotic cytokine IFN-γ. Furthermore, clinical studies have revealed that human NK cells can kill primary human HSCs and that the ability of NK cells from HCV patients to kill HSCs is enhanced and correlates inversely with the stages of liver fibrosis. IFN-α treatment enhances, while other factors (e.g., alcohol, TGF-β) attenuate, the cytotoxicity of NK cells against HSCs, thereby differentially regulating liver fibrogenesis. In addition, the mouse liver lymphocyte population is also enriched for natural killer T (NKT) cells, whereas human liver lymphocytes have a much lower percentage of NKT cells. Many studies suggest that NKT cells promote liver fibrogenesis by producing pro-fibrotic cytokines such as IL-4, IL-13, hedgehog ligands, and osteopontin; however, NKT cells may also attenuate liver fibrosis under certain conditions by killing HSCs and by producing IFN-γ. Finally, the potential for NK and NKT cells to be used as therapeutic targets for anti-fibrotic therapy is discussed. This article is part of a Special Issue entitled: Fibrosis: Translation of basic research to human disease.