自然杀伤T淋巴细胞与肝脏疾病

自然杀伤T淋巴细胞（natural killer T cells，NKT细胞）是一类同时表达恒定的T淋巴细胞受体（TCR）αβ（人为Vα24／Vβ11，鼠为Vα14／Vβ8）和NK细胞标志的T细胞亚群；主要起源于胸腺，发育成熟过程大多依赖于MHC-Ⅰ类样分子CD1d；主要分布于肝脏、骨髓、胸腺等器官，约占小鼠肝脏内成熟T淋巴细胞（T细胞）的30％，占人类肝脏T细胞的10％，外周血也有少量分布；主要经抗原提呈细胞表面CD1d提呈的糖脂类抗原活化，并迅速地释放大量的IFNγ和IL-4等细胞因子，通过调节Th1／Th2细胞间的平衡，在自身免疫性疾病、抗感染、抗肿瘤等方面发挥重要的作用。近年研究表明，NKT细胞与肝脏疾病关系密切，可能参与了肝炎、肝硬化、肝癌等诸多肝脏疾病的发生与发展。     

细胞因子诱导的肿瘤杀伤细胞的临床应用

细胞因子诱导的杀伤细胞（CIK）是一类异质细胞群,由上世纪80年代中期Schmidt-wolf从外周血单核细胞中诱导产生,同时表达CD3和CD56两种膜蛋白分子,兼具T淋巴细胞强大的杀瘤活性和NK细胞的非MHC限制性,故又被称为NK细胞样T淋巴细胞。与以往报告的一些抗肿瘤效应细胞相比,CIK细胞杀瘤活性更强、杀瘤谱更广。     

自然杀伤性T细胞在肝病中的功能作用

<正>自然杀伤性T(natural killer T cell,NKT)细胞是非特异性T淋巴细胞的一类亚群,可同时表达自然杀伤细胞及T细胞的相关受体,与自然杀伤(natural killer,NK)细胞共享部分表型及功能[1]。NKT细胞可被分为两类亚群:Ⅰ型(iNKT)及Ⅱ型NKT细胞(iiNKT)。其中iNKT也被称为经典NKT,其可以     

糖皮质激素诱导的肿瘤坏死因子受体相关蛋白及其配体在肝脏疾病中的作用

糖皮质激素诱导的肿瘤坏死因子受体(GITR)属于肿瘤坏死因子受体家族,与其特异性配体GITRL结合后,所介导的下游信号既可以作为协同刺激分子,促进效应T淋巴细胞增殖与细胞因子分泌;还可以影响调节性T淋巴细胞增殖和抑制效应T淋巴细胞的功能,从而调控效应T淋巴细胞的炎症反应与杀伤肿瘤细胞的作用。GITRL主要表达于抗原递呈细胞且有胞内结构域,与GITR结合后,可以通过受体/配体逆向信号从而影响抗原递呈细胞的功能。在肝脏疾病中,GITRL/GITR信号不仅与肝移植术后和基因治疗中免疫排异反应有关,也与肿瘤免疫微环境形成、肿瘤的免疫逃逸有关。GITRL/GITR在其他肝脏疾病发生和进展中的作用仍有待进一步研究。     

自然杀伤T细胞在病毒感染性疾病中的特征及研究进展

自然杀伤T细胞(natural killer T cells,NKT细胞)属于T淋巴细胞,能特异性识别抗原递呈细胞表面主要组织相容性复合体I类样分子CDld递呈的糖脂类抗原.活化的NKT细胞能发挥抗病毒感染和抗肿瘤等作用,参与机体重要的免疫反应.本文对NKT细胞抗病毒作用的相关进展进行综述,同时分析NKT细胞参与肝损伤等慢性病毒感染的发病进程.     

原发性胆汁性肝硬化的细胞免疫学发病机制

原发性胆汁性肝硬化（PBC）是一种器官特异性的进行性自身免疫疾病,常见于女性,以肝脏门脉周围的淋巴细胞浸润,胆管上皮细胞特异性损伤以及血清中高滴度抗线粒体抗体（AMA）为主要特征。最新的PBC研究采用了CD4启动子控制下的TGFβ受体2显性失活（dnTGFβRⅡ）小鼠模型,这种小鼠模型很好地模拟了PBC患者的典型特征。在这种小鼠的基因背景下,通过分别敲除Rag1,μ以及CD1d基因建立了多种双基因缺陷鼠,通过研究发现T细胞,B细胞以及CD1d限制的NKT细胞等对肝脏淋巴细胞浸润,胆管上皮细胞损伤以及AMA的产生发挥着重要的作用。一系列的细胞免疫学实验结果显示,是CD8＋T细胞而非CD4＋T细胞在肝脏损伤过程中起着决定性的作用,而B细胞除分泌抗自身抗体之外,还具有抑制PBC发生的免疫调节作用。这些机制的研究为揭示人类PBC疾病的细胞免疫学致病机理提供了有力的证据和依托     

CD4＋CD25＋调节性T细胞与肿瘤免疫研究进展

最早关于调节性T细胞（Tregulatory,Treg）与实体瘤关系的研究是2001年在非小细胞肺癌和卵巢癌患者的肿瘤浸润淋巴细胞中发现Treg细胞比例上调,此后在胃肠道肿瘤、胰腺癌、乳腺癌、恶性黑色素瘤等患者的外周血和肿瘤局部微环境均发现Treg细胞数目增加、比重升高,显著高于正常人,提示肿瘤可使Treg数量明显增多,从而导致T细胞功能紊乱,抑制宿主的抗肿瘤免疫应答,使抗肿瘤效应细胞功能下调。     

自然杀伤T细胞与肺部疾病

自然杀伤(NK)T细胞是一种非经典的天然T细胞亚群, 可以识别CD1d分子递呈的脂质抗原。根据T细胞受体基因编码序列的可变性, 通常将NKT细胞分为2个亚群, 即Ⅰ型NKT细胞和Ⅱ型NKT细胞。Ⅰ型NKT细胞可以分为NKT1、NKT2、NKT17和NKT10细胞等亚群。研究显示NKT细胞在肺部疾病发生发展中发挥重要作用。本文将对NKT细胞的分类、发育分化及其在肺部疾病中的作用进行探讨。     

消化系恶性肿瘤病人LAK细胞和NK细胞功能与表型的变化

通过观察20例正常人和24例消化系恶性肿瘤病人外周血自然杀伤细胞(NK)和淋巴因子激活的杀伤细胞(LAK)的活性变化,以及加用重组白细胞介素2(rIL-2)刺激前后T淋巴细胞表型变化。结果发现肿瘤病人的NK细胞活性明显下降,但经rIL-2激活后LAK细胞活性得到明显提高,其溶解率接近正常水平。肿瘤病人的总T淋巴细胞(CD_(3+))和辅助/诱导T淋巴细胞(CD_(4+))水平低于正常,但抑制/杀伤淋巴细胞(CD_(8+))水平正常。辅助/诱导淋巴细胞与抑制/杀伤淋巴细胞之比为1.18,低于正常水平(1.55)。经加入rIL-2培养后,CD_(3+)和CD_(8+)淋巴细胞的比率明显升高并达正常水平。而在正常人此变化不明显,且加用rIL-2培养与不加者无显著差异。IL-2受体的表达正常人与肿瘤病人无异。结果显示胃肠道恶性肿瘤病人的免疫机制受到抑制,但能被IL-2提高至正常水平。     

自然杀伤细胞在肝脏疾病中的作用

自然杀伤（NK ）细胞是1975年发现的一类胞内含有大颗粒的淋巴细胞,广泛分布于机体的淋巴样和非淋巴样的组织内,具有免疫防御与免疫监视的功能。NK细胞具有独特的表型,在各种器官中的频数从高到低依次为肺、肝、外周血、脾、骨髓、淋巴结、胸腺,功能受组织微环境影响明显,主要通过肿瘤坏死因子相关凋亡诱导配体（TRAIL）介导的细胞毒性作用和分泌细胞因子清除病原体和抑制肿瘤发生。当前,NK细胞在肝脏疾病中的作用研究获得了较大的进展。如肝脏 NK 细胞与外周NK细胞相比,可分泌更多的细胞杀伤因子,发挥更强的抗肿瘤作用［1］;慢性 HCV 感染及利用 IFN-α治疗时,肝脏NK细胞可被活化,从而控制肝炎和肝纤维化;同时,慢性HCV感染或长期酒精摄入也可削弱肝脏NK细胞的杀伤作用而致病。本文总结了NK细胞作为潜在的肝脏疾病治疗靶标,在肝内抗病毒、抗纤维化、抗肿瘤作用研究中的最新进展。     

Tumor microenvironment in primary liver tumors: A challenging role of natural killer cells

In the last years, several studies have been focused on elucidate the role of tumor microenvironment(TME) in cancer development and progression. Within TME, cells from adaptive and innate immune system are one of the main abundant components. The dynamic interactions between immune and cancer cells lead to the activation of complex molecular mechanisms that sustain tumor growth. This important cross-talk has been elucidate for several kind of tumors and occurs also in patients with liver cancer, such as hepatocellular carcinoma(HCC) and intrahepatic cholangiocarcinoma(iCCA). Liver is well-known to be an important immunological organ with unique microenvironment. Here, in normal conditions, the rich immune-infiltrating cells cooperate with non-parenchymal cells, such as liver sinusoidal endothelial cells and Kupffer cells, favoring self-tolerance against gut antigens. The presence of underling liver immunosuppressive microenvironment highlights the importance to dissect the interaction between HCC and iCCA cells with immune infiltrating cells, in order to understand how this cross-talk promotes tumor growth. Deeper attention is, in fact, focused on immune-based therapy for these tumors, as promising approach to counteract the intrinsic anti-tumor activity of this microenvironment. In this review, we will examine the key pathways underlying TME cell-cell communications, with deeper focus on the role of natural killer cells in primary liver tumors, such as HCC and iCCA, as new opportunities for immune-based therapeutic strategies.     

Hiding Lipid Presentation: Viral Interference with CD1d-Restricted Invariant Natural Killer T (iNKT) Cell Activation

The immune system plays a major role in protecting the host against viral infection. Rapid initial protection is conveyed by innate immune cells, while adaptive immunity (including T lymphocytes) requires several days to develop, yet provides high specificity and long-lasting memory. Invariant natural killer T (iNKT) cells are an unusual subset of T lymphocytes, expressing a semi-invariant T cell receptor together with markers of the innate NK cell lineage. Activated iNKT cells can exert direct cytolysis and can rapidly release a variety of immune-polarizing cytokines, thereby regulating the ensuing adaptive immune response. iNKT cells recognize lipids in the context of the antigen-presenting molecule CD1d. Intriguingly, CD1d-restricted iNKT cells appear to play a critical role in anti-viral defense: increased susceptibility to disseminated viral infections is observed both in patients with iNKT cell deficiency as well as in CD1d- and iNKT cell-deficient mice. Moreover, viruses have recently been found to use sophisticated strategies to withstand iNKT cell-mediated elimination. This review focuses on CD1d-restricted lipid presentation and the strategies viruses deploy to subvert this pathway.     

Induced pluripotency as a potential path towards iNKT cell-mediated cancer immunotherapy

Invariant natural killer T (iNKT) cells are characterized by the expression of an invariant Vα14-Jα18 paired with Vβ8/7/2 in mice, and Vα24-Jα18 with Vβ11 in humans, that recognizes glycolipids, such as α-galactosylceramide (α-GalCer), presented on the MHC class I-like molecule, CD1d. iNKT cells act as innate T lymphocytes and serve as a bridge between the innate and acquired immune systems. iNKT cells augment anti-tumor responses by producing IFN-γ, which acts on NK cells to eliminate MHC-non-restricted (MHC(-)) target tumor cells, and on CD8(+) cytotoxic T lymphocytes to directly kill MHC-restricted (MHC(+)) tumor cells. Thus, when iNKT cells are activated by α-GalCer-pulsed dendritic cells, both MHC(-) and MHC(+) tumor cells can be effectively eliminated. Both of these tumor cell types are simultaneously present in cancer patients, and at present iNKT cells are only the cell type capable of eliminating them. Based on these findings, we have developed iNKT cell-targeted adjuvant immunotherapies with strong anti-tumor activity in humans. However, two-thirds of patients were ineligible for this therapy due to the limited numbers of iNKT cells in their bodies. In order to overcome the problem in cancer patients, we successfully established a method to generate iNKT cells with adjuvant activity from embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). In this review, we would like to outline the clinical potential for iNKT cells derived from ESCs and iPSCs for cancer immunotherapy, and the technical hurdles that must be overcome if we achieve effective ESC/iPSC-mediated cancer therapies.     

Human invariant natural killer T cells: implications for immunotherapy

Human invariant natural killer T cells are a unique lymphocyte population that have an invariant T-cell receptor and recognize glycolipids instead of peptides in the restriction of CD1d molecules. These natural killer T cells play important roles in anti-tumor immunity, transplantation immunity, allergy, autoimmunity and microbial immunity. Since human natural killer T cells show high-level biological activity such as cytokine production, an anti-tumor effect and regulatory T-cell control, they may be a useful tool in immune-cell therapy. In this review, we summarize the immune responses mediated by human natural killer T cells, especially in tumor and transplantation immunity, and discuss their potential in clinical applications.     

Modulation of human natural killer T cell ligands on TLR-mediated antigen-presenting cell activation

Invariant natural killer T (iNKT) cells are a subset of nonconventional T cells recognizing endogenous and/or exogenous glycolipid antigens in the context of CD1d molecules. It remains unclear whether innate stimuli can modify the profile of endogenous lipids recognized by iNKT cells on the surface of antigen-presenting cells (APCs). We report that activation of human APCs by Toll-like receptor ligands (TLR-L) modulates the lipid biosynthetic pathway, resulting in enhanced recognition of CD1d-associated lipids by iNKT cells, as defined by IFN-gamma secretion. APC-derived soluble factors further increase CD1d-restricted iNKT cell activation. Finally, using soluble tetrameric iNKT T cell receptors (TCR) as a staining reagent, we demonstrate specific up-regulation of CD1d-bound ligand(s) on TLR-mediated APC maturation. The ability of innate stimuli to modulate the lipid profile of APCs resulting in iNKT cell activation and APC maturation underscores the role of iNKT cells in assisting priming of antigen-specific immune responses.     

肝脏天然免疫研究进展

从肠道至肝脏的血液中富含细菌产物、环境毒素和食物抗原。肝脏依靠强大的天然免疫系统能快速有效地清除外来物质,而不引起有害免疫应答。肝脏富含天然免疫细胞,包括巨噬细胞、自然杀伤细胞、自然杀伤T细胞和γδT细胞。肝细胞表达多种Toll样受体（TLRs）,其信号途径的激活在天然免疫应答中发挥重要作用。此外,肝脏通过合成大量可溶性模式识别受体和补体成分在宿主防御微生物入侵和肿瘤转化方面发挥重要作用。肝脏天然免疫系统还积极参与肝脏炎症、损伤和再生的过程。     

Peripheral blood progenitor cell product contains Th1-biased noninvariant CD1d-reactive natural killer T cells: implications for posttransplant survival

OBJECTIVE: Bone marrow (BM) Th1 populations can contribute to graft-vs-leukemia responses. Granulocyte/granulocyte macrophage colony-stimulating factor (CSF)-mobilized peripheral blood progenitor cells (PBPC) have become widely accepted alternatives to BM transplantation. T cells coexpressing natural killer cell proteins (NKT) include a CD1d-reactive subset that influences immunity by rapidly producing large amounts of Th1 and/or Th2 cytokines dependent upon microenvironment and disease. There are two types of CD1d-reactive NKT. iNKT express a semi-invariant T-cell receptor-alpha. Other noninvariant CD1d-reactive NKT from BM and liver produce large amounts of interleukin-4 or interferon-gamma, respectively, and within the intestine can be biased in either direction. Recent data suggests that NKT might contribute to clinical benefits of PBPC. MATERIALS AND METHODS: To address these issues, we phenotypically and functionally studied PBPC NKT. RESULTS: Similarly to BM, NKT-like cells were common in allogeneic and autologous PBPC, there were relatively few classical iNKT, but high CD1d-reactivity concentrated in NKT fractions. Significantly, PBPC CD1d-reactive cells were relatively Th1-biased and their presence was associated with better prognosis. Granulocyte CSF treatment of BM to yield PBPC in vivo as well as in vitro Th2-polarizes conventional T cells and iNKT. However, granulocyte CSF treatment of BM in vitro produced Th1-biased NKT, providing a mechanism for opposite polarization of NKT from BM vs PBPC. CONCLUSIONS: These results suggest distinct Th1 CD1d-reactive NKT cells could stimulate anti-tumor responses from those previously described, which can suppress graft-vs-host disease.     

Immune Function in Alcoholism: A Controlled Study

Several studies have shown an increased risk for infection and cancer in alcoholic patients. The mechanisms for such observations remain largely unknown. In an effort to investigate the possibility of immunological dysfunction in alcoholism, we studied three immune parameters in 47 hospitalized chronic alcoholic patients and 47 age-and sex-matched normal controls. The immune measures were: (1) lymphocyte phenotyping, with estimates of percentages of T cells, B cells, T helpers, T suppressors, natural killer (NK) cells, and cells carrying the activation markers IL₂R₁ and l₂; (2) NK cell activity; and (3) lymphokine-activated killer cell activity. Results indicate a significant increase in the IL₂R and l₂ lymphocyte markers in alcoholic patients compared with matched controls. We also found a nonsignificant trend for a decrease in the percentage of suppressor T cells in the alcoholic group, as well as a trend for a negative correlation between the percentage of T suppressor cells and age. There were no significant differences in either NK or lymphokine-activated killer cell activities between the two groups. Furthermore, there were no significant associations between duration and intensity of alcohol consumption and any of the immune measures. These results suggest subtle alterations in immune regulation in alcoholic patients that cannot be explained solely on the basis of duration and/or amount of alcohol consumed.     

The vitamin D receptor is required for iNKT cell development

CD1d-reactive natural killer T (NKT) cells with an invariant T cell receptor Valpha14 rearrangement are a unique subset of lymphocytes, which play important roles in immune regulation, tumor surveillance, and host defense against pathogens. Vitamin D is a nutrient/hormone that has been shown to regulate conventional T cell responses but not T cell development. The data show that expression of the vitamin D receptor (VDR) is required for normal development and function of iNKT cells. The iNKT cells from VDR KO mice are intrinsically defective and lack T-bet expression. VDR KO iNKT cells fail to express NK1.1, although they express normal levels of CD122. Extrinsic factors that impact iNKT cell development and function in VDR KO mice include a failure of the liver to support homeostatic proliferation and reduced thymic expression of CD1d and other factors important for optimal antigen presentation in the thymus. In addition, VDR KO iNKT cells were intrinsically defective even when WT antigen-presenting cells were used to stimulate them.