NK细胞和NKT细胞在病毒性肝炎中的作用

NK细胞(Natural killer cells)和NKT细胞(Natural killer T cells)参与机体的天然免疫反应。NK细胞在肝炎病毒感染的早期免疫反应中起到重要作用,而慢性病毒性肝炎患者NK细胞功能降低。另外,动物实验显示NKT细胞可致肝组织损伤并能抑制肝炎病毒的复制。因此通过调节NK细胞和NKT细胞的功能治疗病毒性肝炎将有可能成为一种新的策略。     

他克莫司对肾移植受者外周血NK和NKT细胞比例的影响及临床意义

他克莫司(Tacrolimus)是一种强效免疫抑制剂,现已广泛应用于肾脏、肝脏及心脏移植,有效减低了排异反应的发生,提高了移植受者的存活率.但是他克莫司个体药代动力学差异大,不同个体对其血药浓度的敏感性及耐受性有差异,故单纯依靠血药浓度监测不能有效反映移植受者的免疫状态.因此如何了解移植受者的免疫状态,指导免疫抑制剂的个体化应用,在免疫抑制不足及免疫过度之间寻找平衡,成为困扰移植医生的问题.NK细胞(natrural killer cell)是天然免疫系统的主要效应细胞.     

黄芪多糖诱导的树突状细胞增强CIK细胞的杀伤作用

目的:观察黄芪多糖(Astragalus polysaccharides,APS)对树突状细胞(Dendritic cell,DC)抗原提呈功能的影响,并和同源CIK(Cytokine induced killer)细胞共培养,观察DC-CIK和黄芪多糖诱导DC-CIK细胞杀伤A549肺腺癌细胞的活性.方法:提取健康供血者的外周血单个核细胞(PBMC),常规诱导出DC与CIK细胞后,将其共培养,观察黄芪多糖对DC表型变化的影响,定量检测DC-CIK和黄芪多糖诱导DC-CIK细胞培养上清中的IFN-γ和IL-12;并用MTT法测定其体外细胞毒活性.结果:黄芪多糖能提高DC表面分子CD40、CD80、HLA-DR的表达,经黄芪多糖诱导的DC活化的CIK,对A549肺腺癌细胞的杀伤活性高于单纯DC-CIK细胞,差异显著(P＜0.05).结论:黄芪多糖能增强DC的抗原提呈功能,证实黄芪多糖诱导的DC能明显提高CIK对肿瘤细胞的杀伤活性,具有更广阔的应用前景.     

人外周血NK细胞及NKT细胞受体及亚群的差异表达与类风湿关节炎的关系

目的:探讨初诊类风湿关节炎(RA)患者的外周血NK和NKT细胞的活化性、抑制性受体及亚群表达水平的变化,揭示其在RA发病中的可能机制。方法:检测32例初诊RA患者和15例健康人的外周血NK和NKT细胞及其活化性受体和抑制性受体,对自发和刺激后的NK、NKT细胞分泌的IFN-γ、NKT细胞和CD107a+NK细胞进行检测,分析各细胞亚群与临床指标之间的潜在关系。结果:与健康对照组相比,初诊RA患者的NK细胞的比例显著降低(P=0.026);RA患者NK细胞活化性受体NKG2D+,NKP46+和NKT细胞活化性受体NKG2C+,NKG2D+,NKP46+的比例显著增高(P=0.011,P=0.010,P<0.001,P=0.032,P=0.001);NK细胞抑制性受体KIR2DL3+、KIR3DL1+和NKG2A+和NKT细胞抑制性受体KIR2DL3+,NKG2A+的比例显著降低(P=0.002,P=0.002,P=0.014,P=0.027,P=0.002);刺激后的IFN-γ+NK和IFN-γ+NKT细胞的比例,自发和刺激后的CD107a+NK细胞的比例在RA患者中要显著高于对照组(P=0.037,P=0.004,P=0.001,P=0.001)。此外,NK细胞、抑制性NK细胞受体NKG2A+和KIR2DL3+的比例和初诊RA患者的DAS28值显著相关(r=0.357,P=0.045;r=0.399,P=0.024;r=0.468,P=0.021)。结论:人外周血NK细胞及NKT细胞受体及亚群的差异表达、细胞功能的变化可能诱发RA的自身免疫反应。     

中国HIV/AIDS患者NK细胞及NKT细胞变化的检测

目的　探讨HIV感染后机体NK(naturalkillercells)及NKT细胞的变化情况。方法　取外周血细胞 ,用标记荧光的抗体进行染色 ,流式细胞仪分析HIV AIDS患者NK和NKT细胞的变化。结果　HIV AIDS患者NK、NKT细胞和CD4 + T细胞显著低于正常对照 ;CD8+ T细胞显著高于正常对照。HIV AIDS患者NK百分数显著低于正常对照 ,与CD4 + T细胞数量成正比 ,r=0 .2 89,P <0 .0 1 ;NKT细胞数量与CD4 + T细胞数量成正比 ,r =0 .378,P <0 .0 1 ;与CD8+ T细胞数量成正比 ,r =0 .340 ,P <0 .0 1 ;长期不进展组NKT、NK细胞数量与正常对照组差异无显著性。结论　HIV感染可明显降低HIV AIDS患者NK和NKT细胞数量 ,NK和NKT细胞变化与疾病进展密切相关。     

粗江蓠多糖对辐射损伤小鼠NK细胞的影响

目的：研究粗江蓠多糖（Gracilaria Gigas Harvey Polysaccharides,GHPS）对辐射损伤小鼠NK细胞的影响。方法：采用60Coγ射线5Gy全身照射小鼠制造辐射损伤模型,通过乳酸脱氢酶释放法检测不同剂量（10mg/kg,20mg/kg,40mg/kg）的GHPS对辐射损伤小鼠NK细胞杀伤靶细胞能力的影响。结果：辐射对照组小鼠接受60Coγ射线5Gy照射后,NK细胞的活性显著低于正常对照组（P〈0.01）。经腹腔注射（10、20、40）mg/kg GHPS,再接受γ射线5Gy照射后,小鼠NK细胞活性明显高于辐射对照组（P〈0.01）,并有剂量依赖性。结论：5Gyγ射线可以抑制小鼠NK细胞杀伤靶细胞的活性,而GHPS对辐射损伤小鼠的NK细胞有保护作用。     

黄芪多糖对树突状细胞表型及功能成熟的影响

目的 通过体外试验研究黄芪多糖（Astragalus mongholicus, ASP） 对树突状细胞（dendritic cells，DC）功能调节的机制，为进一步阐明黄芪多糖的免疫学活性提供依据。方法 应用流式细胞仪检测技术、扫描电镜技术、酶联免疫吸附试验检测DC表型和功能的各种指标。结果 本实验应用小鼠骨髓来源的DC，通过体外试验证明了黄芪多糖能够提高DC表面分子CD11c和MHCⅡ的表达，并且呈黄芪多糖浓度依赖性；空白组DC的吞噬功能很强，LPS组DC和黄芪多糖处理组DC吞噬功能都明显下降；黄芪多糖能够促进DC白细胞介素-12（IL-12）的表达；电镜观察DC的超微结构，可见黄芪多糖处理组DC突起增多，形态上更加成熟。结论 本实验结果证实了黄芪多糖能促进小鼠骨髓来源的DC表型及功能的成熟。     

NKT细胞亚群及其功能研究进展

NKT细胞是一群兼具NK细胞和T细胞特征的免疫细胞。根据其表达的TCR类型及发育是否依赖于CD1d分子,可将其分为三类:I型NKT细胞、II型NKT细胞和NKT样细胞。NKT细胞活化后,能够迅速产生IFN-γ、IL-4等多种细胞因子,并正向或负向调节免疫应答。由于NKT细胞数量较少且功能复杂,对NKT细胞亚群及其功能认识的不足成为制约其临床应用的瓶颈。本文对NKT细胞亚群及其功能进行综述,阐明了NKT细胞在免疫应答和免疫调节中发挥的重要作用,并指出某些NKT细胞亚群研究的不足。随着人们对NKT细胞亚群及其功能的深入研究,以NKT细胞为主体的免疫治疗具有巨大的临床应用前景。     

NKT细胞

NKT细胞是一个特殊的T细胞亚群 ,因表达NK细胞的表面标志NK1 1而得名。NKT细胞的共受体表型主要是CD4 CD8 ,也可以是CD4+ ,少数为CD8+ 。NKT细胞最大的特征是其TCRαβ中的α链编码基因在同一种动物中是恒定的 ,而β链编码的基因极其有限。NKT细胞在免疫调节、抗肿瘤和自身免疫的调节中起重要作用     

The differential effect of stress on natural killer T (NKT) and NK cell function

When C57Bl/6 mice were exposed to restraint stress for 12 h or 24 h, lymphocytopenia was induced in the liver, spleen, and thymus. We examined which types of lymphocytes were sensitive or resistant to such stress by a immunofluorescence test. T cells of thymic origin were sensitive while NKT and NK cells were resistant. In contrast to the increase in the proportion of NK cells, NK activity of liver lymphocytes against YAC-1 targets decreased at 24 h after stress. On the other hand, their NKT cytotoxicity against syngeneic thymocytes increased in parallel with an increase in their proportion. In perforin -/- B6 mice and B6-gld/gld (Fas ligand-) mice, NK cells were found to mediate cytotoxicity through perforin while NKT cells mediated self-reactive cytotoxicity through Fas ligand. These results suggest that stress increases the proportion of both NK and NKT cells, but that NK cytotoxicity is suppressed while self-reactive NKT cytotoxicity is not, due to a diversity of their functional mechanisms.     

NK cells and NKT cells collaborate in host protection from methylcholanthrene-induced fibrosarcoma

NK1.1(+) V(alpha)14J(alpha)281(+) (NKT) cells can be induced by IL-12 therapy to mediate tumor rejection; however, methylcholanthrene (MCA)-induced fibrosarcoma is the only tumor model described where NKT cells play a natural role in controlling tumor initiation. From our previous study in C57BL/6 mice it remained unclear whether NK cells were also involved in this natural response. Herein, to discriminate the function of NK and NKT cells, we have evaluated fibrosarcoma development in mice deficient in NKT cells, but not NK cells, and mice deficient in NK cells, but not NKT cells. The results indicate that both NK cells and NKT cells are essential and collaborate in natural host immunity against MCA-induced sarcoma. In contrast, sarcoma incidence and growth rate were reduced using IL-12 therapy, this effect was mediated in the absence of T cells (including NKT cells), but not NK cells.     

Relative contribution of NK and NKT cells to the anti-metastatic activities of IL-12

Conventional T cells, NK cells and NKT cells have been implicated in the anti-tumor activities induced by IL-12. Here we show that IL-12-induced immune responses are partially impaired in T and NKT cell-deficient RAG-2(-/-) mice, and in NKT cell-deficient CD1(-/-) mice. In response to a small dose (<1000 U) of IL-12, RAG-2(-/-) and CD1(-/-) mice demonstrated reduced cytotoxicity, serum IFN-gamma elevation and anti-metastatic activities; in contrast, in response to a high dose (>2000 U) of IL-12, the IL-12-induced immune responses of RAG-2(-/-) and CD1(-/-) mice were indistinguishable from wild-type mice. The defective responses to low-dose IL-12 of RAG-2(-/-) mice were corrected by adoptive transfer of NKT cells but not NK cells. These findings indicate that both NK and NKT cells contribute to the anti-metastatic responses induced by IL-12, and that NKT cells are mostly responsible for the low-dose activities of this cytokine.     

The Role of Invariant NKT Cells in Pre-Eclampsia

Problem  Recent data suggest a dominant role of the innate, rather than the adaptive immune system in pregnancy-related immunoregulation. Invariant NKT (iNKT) cells represent a link between the innate and the acquired immune systems; however, little is known about how they function in pre-eclampsia. The aim of our study was to investigate the possible role of iNKT cells in the pathogenesis of pre-eclampsia.
Method of study  Human peripheral blood samples were obtained from pre-eclamptic, healthy pregnant- and non-pregnant women. Freshly separated peripheral blood mononuclear cells were immediately labeled with anti-perforin-, anti-CD69-, anti-CD95-, anti-NKG2A-, anti-NKG2D-, anti-IFN-γ and anti iNKT antibodies and analyzed by flow cytometry.
Results  Pre-eclamptic patients demonstrated increased CD69, perforin and IFN-γ expression, which could be explained by dysregulation of NK cell receptor expression. These Th1 polarized cells were less susceptible to apoptosis than iNKT cells from healthy pregnant women.
Conclusion  Our data suggest that activated iNKT cells of pre-eclamptic women have an increased cytotoxic potential, which may be because of altered expression of NK cell inhibitory and activating receptors.     

Activated CD56(+) lymphocytes (NK+NKT) mediate immunomodulatory and anti-viral effects during Japanese encephalitis virus infection of dendritic cells in-vitro

Japanese encephalitis virus (JEV) remains one of the major causative agents of pediatric encephalitis. Interaction of dendritic cells (DCs) with innate lymphocytes (NK and NKT) represents a crucial event during anti-viral innate immune response. In the current study, we have tried to understand the interaction between JEV, human monocyte derived DCs (MDDCs), and CD56⁺ cells (NK+NKT) in-vitro. We have used two JEV strains (i) JE057434 (neurovirulent, wild-type) and (ii) SA14-14-2 (non-neurovirulent, live-attenuated vaccine) to investigate the effect of viral virulence on the functional status of primary human MDDCs. Our preliminary results indicate that replicating JEV induces MDDCs maturation via PI3K and p38 pathways. We also show that the presence of IL2-activated CD56⁺ cells impart both immunomodulatory and anti-viral effects on DCs infected with JEV. Mechanistic studies illustrate that, IL2-activated CD56⁺ lymphocytes mediated immunomodulation occurs through direct cell-to-cell contact and TNFα, while the anti-viral effect is dependent on direct cell-to-cell contact.     

NK and NKT Cells in Aging and Longevity: Role of Zinc and Metallothioneins

Introduction  During aging, dysregulated immune functions occur contributing to increased susceptibility to morbidity and mortality. However, these dysregulations are normally counterbalanced by continuous adaptation of the body to the deteriorative changes occurring over time. These adaptive changes well occur in healthy centenarians. Discussion  Both innate (natural) and adaptive (acquired) immune responses decline with advancing age. Natural killer (NK) and natural killer T (NKT) cell cytotoxicity, representing one of best models of innate immune response, decreases in aging as well as interferon-γ (IFN-γ) production by both activated types of cells. Both NK and NKT cell cytotoxicity and IFN-γ production increase in very old age with respect to normal aging, especially by NKT cells bearing TCRγδ. The role played by zinc and metallothioneins (MT) is crucial because this affects NK and NKT cell development, maturation, and functions. In particular, some MT polymorphisms are involved in maintaining innate immune response and intracellular zinc ion availability in aging with thus a role of MT genetic background to escape some age-related diseases with subsequent healthy aging and longevity.     

NKG2D performs two functions in invariant NKT cells: direct TCR-independent activation of NK-like cytolysis and co-stimulation of activation by CD1d

Invariant NKT cells are important in the activation and regulation of immune responses. They can also function as CD1d-restricted killer cells. However, the role of activating innate NK-cell receptors expressed on NKT cells in triggering cytolytic function is poorly characterized. Here, we initially confirmed that the cellular stress-ligand receptor NKG2D is expressed on CD4- NKT cells, whereas most CD4+ NKT cells lack this receptor. Interestingly, NKG2D+ NKT cells frequently expressed perforin, and both NKG2D and perforin localized at the site of contact with NKG2D ligand-expressing target cells. CD4- NKT cells degranulated in response to NKG2D engagement in a redirected activation assay independent of stimulation via their invariant TCR. NKT cells killed P815 cells coated with anti-NKG2D mAb and CD1d-negative K562 tumor target cells in an NKG2D-dependent manner. Furthermore, NKG2D engagement co-stimulated TCR-mediated NKT-cell activation in response to endogenous CD1d-presented ligands or suboptimal levels of anti-CD3 triggering. These data indicate that the CD4- subset of human NKT cells can mediate direct lysis of target cells via NKG2D engagement independent of CD1d, and that NKG2D also functions as a co-stimulatory receptor in these cells. NKG2D thus plays both a direct and a co-stimulatory role in the activation of NKT cells.     

C57BL/6小鼠不同组织器官中NKT细胞的比较

目的比较C57BL/6小鼠肝脏、肺脏、脾脏和肠系膜淋巴结中NKT细胞的含量、亚型和功能的特点。方法分离正常C57BL/6小鼠肝脏、肺脏、脾脏和肠系膜淋巴结的淋巴细胞,利用细胞表面分子染色的方法,观察不同组织器官中CD3+NK1.1+NKT细胞及其亚型的含量;淋巴细胞经过PMA和离子霉素刺激后,应用细胞内细胞因子染色的方法,通过流式细胞仪观察NKT细胞IFN-γ、IL-4、IL-9和IL-17的产生情况。结果肝脏中NKT细胞的含量为(25.2±12)%,显著高于肺脏、脾脏和肠系膜淋巴结。肝脏、脾脏和肠系膜淋巴结中NKT细胞以CD4+细胞亚群为主,而肺脏中NKT细胞以CD4-CD8-亚群为主,同时肠系膜淋巴结的NKT细胞中存在CD4+CD8+亚群。不同组织器官中NKT细胞IFN-γ、IL-4、IL-9和IL-17产生的能力有差别。结论 C57BL/6小鼠肝脏、肺脏、脾脏和肠系膜淋巴结的NKT细胞在含量、表型和功能方面可能存在明显的差异。     

Activated NKT cells imprint NK‐cell differentiation,functionality and education

NK cells represent a vital component of the innate immune system. The recent discoveries demonstrating that the functionality of NK cells depends on their differentiation and education status underscore their potential as targets for immune intervention. However, to exploit their full potential, a detailed understanding of the cellular interactions involved in these processes is required. In this regard, the cross‐talk between NKT cells and NK cells needs to be better understood. Our results provide strong evidence for NKT cell‐induced effects on key biological features of NK cells. NKT‐cell activation results in the generation of highly active CD27^high NK cells with improved functionality. In this context, degranulation activity and IFNγ production were mainly detected in the educated subset. In a mCMV infection model, we also demonstrated that NKT‐cell stimulation induced the generation of highly functional educated and uneducated NK cells, crucial players in viral control. Thus, our findings reveal new fundamental aspects of the NKT‐NK cell axis that provide important hints for the manipulation of NK cells in clinical settings.