Peptide Mimicry of AICL Inhibits Cytolysis of NK Cells by Blocking NKp80-AICL Recognition

AICL has been identified as a ligand of the activating NK cell receptor NKp80, but the interaction sites of NKp80-AICL were unknown. In this study, a 3-D model of AICL was constructed by using online server 3D-JIGSAW. Three highly conserved sequences of AICL on the surface of the AICL 3-D model were synthesized, and named as P1, P2 and P3, respectively. Flow cytometric analysis demonstrated that these peptides were able to compete with anti-NKp80 mAb on NKp80 binding activity in a dose-dependent manner. Moreover, P1 or P2 exerted inhibitory effects on NKp80-AICL mediated cytotoxicity of both fresh PBMCs and purified NK cells in ⁵¹Cr release cytotoxicity assay. These results demonstrated that P1 and P2 sequences on AICL might be considered as the potential sites of NKp80-AICL interaction.     

Functions of Human Decidual NK Cells

The main population of lymphocytes found in the human decidua during early pregnancy are NK-like cells with a distinctive phenotype, CD56^bright CD16^? CD3^?. These cells are in close association with invading trophoblast that may be their in vivo target. We have examined three aspects of decidual NK function in vitro: cytotoxicity, proliferation, and cytokine production. The functional assays indicate uterine lymphocytes differ fundamentally from both PBL and even from classical circulating NK cells. Their role in the establishment of normal pregnancy remains unknown.     

Immunosuppressive Properties of Monoclonal Antibodies and Human Polyclonal Alloantibodies to the R80K Protein of Trophoblast

PROBLEM: The R80K protein on human trophoblast is antigenically polymorphic, and in all placentae of successful pregnancies, the protein is covered by maternal alloantibody. Alloantibody eluted from human placenta has been shown to inhibit killing by human NK cells. Do those antibodies to R80K that inhibit NK killing also affect the murine abortion models? METHODS: We made three murine monoclonal antibodies to conserved epitopes on human R80K, all of which also reacted with the homologous murine molecule. One antibody only, BA11, suppressed NK cytotoxicity to K562 and of mouse spleen NK cells to murine trophoblast. All three were tested in mouse models of abortion: the CBA × DBA/2 model with a high resorption rate of F1 embryos compared with the parental strains, an endotoxin induced abortion/resorption model and a third model in which the pregnant mouse is subject to sonic stress. CONCLUSION: Those IgG antibodies eluted from microvesicles which bound to K562, and one of the three monoclonals, BA11, inhibited NK killing. The antibodies react with the murine molecule, and BA11 inhibited abortion in all three mouse abortion models. This reinforces the thesis that interference with NK killing can influence abortion/resorption in mice, and the BA11 antibody may effect similar results in analogous human situations.     

Uterine NK Cells and Trophoblast HLA Class I Molecules

PROBLEM: To investigate the proposal that NK cells in decidua may control trophoblast migration during implantation of the human placenta. METHOD: Use Mab specific for HLA-G and for HLA-C in association with flow cytometry and immunoprecipitation to determine the expression of these HLA molecules by trophoblast. Expression of Killer inhibitory/activatory receptors (KIR/KAR) and the CD94 receptor by decidual NK cells was also studied. RESULTS: Extravillous trophoblast expressed HLA-G and HLA-C in both β₂m-associated form and as free heavy chains. KIR and KAR are expressed by decidual NK cells. The repertoire of receptors varied between different women and also between blood and decidual NK cells from the same women. The expression of CD94 was also different between blood and decidual NK cells. CONCLUSION: The recognition of HLA-G/HLA-C by KIR/KAR and CD94 could provide a mechansm by which decidual NK cells control trophoblast migration.     

Liver-Resident NK Cells Control Antiviral Activity of Hepatic T Cells via the PD-1-PD-L1 Axis

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NK Cell Tolerance and the Maternal–Fetal Interface

Natural killer (NK) cells play a fundamental role in the innate immune response through their ability to secrete cytokines and kill target cells without prior sensitization. These effector functions are central to NK cell anti-viral and anti-tumor abilities. Due to their cytotoxic nature, it is vital that NK cells have the capacity to recognize normal self-tissue and thus prevent their destruction. In addition to their role in host defense, NK cells accumulate at the maternal-fetal interface and are thought to play a critical role during pregnancy. The close proximity of uterine NK (uNK) cells to fetal trophoblast cells of the placenta would seemingly lead to catastrophic consequences, as the trophoblast cells are semi-allogeneic. A fundamental enigma of pregnancy is that the fetal cells constitute an allograft but, in normal pregnancies, they are in effect not perceived as foreign and are not rejected by the maternal immune system. Although the mechanisms involved in achieving NK cell tolerance are becoming increasingly well-defined, further clarification is required, given the clinical implications of this work in the areas of infection, transplantation, cancer and pregnancy. Herein, we discuss several mechanisms of NK cell tolerance and speculate as to how they may apply to uNK cells at the maternal–fetal interface.     

人外周血NK细胞纯化、扩增及克隆化的初步探索

分别采用Panning法、补体裂解法、绵羊红细胞花环法、Percoll不连续密度梯度离心法对NK细胞进行纯化并以流式细胞仪检测其纯度和计数探索NK细胞的体外扩增条件 ,将纯化NK细胞经有限稀释 ,在饲养细胞、IL 2、PHA及LCM等培养条件下进行克隆化培养并进行鉴定。研究表明NK细胞的纯度由纯化前 10 %左右提高到 30 %～ 70 %不等 ,以Percoll不连续密度梯度离心法所获纯度最高 ,约为 70 %。NK细胞的体外扩增在含有IL 2、PHA及条件培养基最显著。每 96孔板可获 4～ 16个CD3 CD5 6 +NK细胞克隆 ,每 96个克隆的细胞数最多可达 2 35× 10 5。     

TWS119对人NK细胞增殖和杀伤甲状腺癌BCPAP细胞的影响

目的 探讨糖原合酶激酶-3β抑制剂TWS119对NK细胞增殖和杀伤功能的影响.方法 从健康人外周血中分离单个核细胞(PBMCs),加入到NK完全培养基培养,分别于第1d和第7d时,加入TWS119 (0 ～8.0μmol/L)诱导培养.培养10 d后,用CCK-8法测定NK细胞增殖和杀伤甲状腺癌BCPAP细胞的能力;采用流式细胞术检测各组NK细胞纯度、颗粒酶和穿孔素的表达.结果 培养10d后,第1天加入TWS119诱导组对NK细胞纯度和增殖呈现抑制作用;而第7天加入在一定浓度范围的TWS119诱导培养时能促进NK细胞的增殖和杀伤指标穿孔素的表达及对甲状腺癌BCPAP细胞的体外杀伤活性.结论 TWS119在一定浓度范围能促进γδT细胞增殖和增强对甲状腺癌BCPAP细胞的杀伤功能.     

Suppressive Effect of a Standardized Mistletoe Extract on the Expression of Activatory NK Receptors and Function of Human NK Cells

Despite long-term use of mistletoe extracts for cancer treatment, their mode of action remains elusive. In this study, it was studied in vitro if mistletoe extract is able to modulate the expression of natural cytotoxic receptors (NCRs) and NKG2D receptor, which stimulate natural killer cell-mediated cytotoxicity. Unexpectedly, a mistletoe extract, ABNOBA viscum Fraxini, inhibited the expression level of NKp46 and NKG2D receptors in dose- and time-dependent manners. The levels of NKp30 and NKG2D receptors were remarkably induced and NKp44 was slightly induced after 48 h treatment with IL-2 and IL-15 in both mRNA and surface expression. The activatory NK receptors were not induced significantly after treatment with IL-12, IL-18, and IL-21 for 48 h. Induction of activatory NK receptors by IL-2 and IL-15 was suppressed almost to the untreated levels by treatment with mistletoe extract, which appeared to induce apoptosis of NK cells in a dose-dependent manner. However, the treatment with IL-2 and IL-15 did not prevent the mistletoe-induced NK-cell death. Mistletoe extract inhibited significantly the cytotoxic activity of resting and IL-2- or IL-15-stimulated NK cells. These results suggest that inhibition of survival and function of NK cells by mistletoe extract may curtail in part the therapeutic effects of mistletoe. Soo Jung Lee, Young-Ok Son, and Hyunjin Kim contributed equally to this article     

The Role of NK Cells and NK Cell Receptors inAutoimmune Disease

Natural killer (NK) cells are the first line of defense against infection and transformation. Additionally, NK cells can play seemingly opposite roles in autoimmune disease. Here, we summarize the functions of NK cells as both regulators and inducers of autoimmune disease. The role NK cells play depends on which cells become targets for NK cell attack. The activity of NK cells is controlled by inhibitory receptors specific for MHC Class I molecules, and by activating receptors with diverse specificities. The ligands for both activating and inhibitory receptors are present on potential target cells. It is the balance in expression of these different ligands that determines NK cell activation and therefore whether the cell becomes a target for NK cell-mediated killing. We further discuss the roles of NK cell receptors and their ligands in autoimmune disease.     

A Unique Monoclonal Antibody mNI-11 Rapidly Enhances Spread Formation in Human Umbilical Vein Endothelial Cells

We previously reported a novel monoclonal antibody (MAb), designated mNI-11, recognizing an adhesion-associated antigen distinct from any previously reported ones. In this article, this adhesion-associated antigen with a molecular weight of about 97 kDa was found to be strongly expressed on human umbilical vein endothelial cells (HUVECs) by fluorescence-activated cell sorter (FACS) analysis. Expression of this antigen on HUVECs was slightly increased in response to the exposure to tumor necrosis factor- (TNF-) or phorbol myristate acetate (PMA). As a biological function exerted by this antigen, it was of great interest that immobilized mNI-11 directly and rapidly enhanced the spread formation of HUVECs, whereas MAbs binding other adhesion-associated antigens such as mNI-58A (anti-CD11a), L130 (anti-CD18), L133.1 (anti-CD31), L178 (anti-CD44), L25.3 (anti-CD49d), or LB-2 (anti-CD54) did not carry such activity under the same conditions. The HUVECs spread formation enhanced by mNI-11 was completely blocked in the presence of a microfilament formation inhibitor, cytochalasin D (CyD), a Ca²⁺-calmodulin inhibitor, W-7, EDTA, and was partially blocked by a microtubule formation inhibitor, nocodazole, a protein kinase C (PKC) inhibitor, H-7, and a protein synthesis inhibitor, cycloheximide (CHX). However, a protein tyrosine kinase (PTK) inhibitor, genistein, did not affect the spread formation under the same conditions. Taken together, it was suggested that the spread formation of HUVECs enhanced by mNI-11 was mainly associated with the influx of Ca²⁺ and microfilament reorganization. In addition, the novel property associated with mNI-11 to enhance the spread formation of HUVECs was possibly mediated through its reaction against a unique epitope on HUVECs.     

Ig-binding Receptors on Human NK Cells as Effector and Regulatory Surface Molecules

The receptors on human natural killer 9NK cells which can specifically bind the Fc portion of immunoglobulin molecules (Fc receptors) have been extensively studied. The best known and studied Fc receptor on human NK cells is FcγRIIIa. Interactions of NK cells with IgG antibodies via this receptor are well known to induce a signal transduction cascade and lead to antibody-dependent cell-mediated cytotoxicity (ADCC) as well as release of various cytokines. In addition, interactions with monomeric IgG and FcγRIIIa have been demonstrated, which result in negative regulation of NK activity and other immunomodulatory effects. Over the past several years, it has also become increasingly appreciated that human NK cells express a variety of other Fc receptors, including FcμR, which also can mediate effector and immunoregulatory functions. Also, a novel form of FcγR has been demonstrated on human NK cells, termed FcγRIIc. Recent molecular studies have shown considerable polymorphism in the genes for FcγIIc and the functional consequences are being dissected. This appears to include cross-talk between FcγRIIIa and at least some forms of FcγRIIc, which may have important functional consequences.     

绒毛膜促性腺激素对NK细胞活性的影响

为探讨绒毛膜促性腺激素 (HCG)对NK细胞活性的影响及其作用的机理 ,将健康人外周血单核细胞(+PBMC组 )及去除单核细胞的 (-PBMC组 )分别与HCG共同孵育后 ,以改良的MTT法检测NK细胞对其靶细胞K5 6 2 的杀伤活性。结果表明 :(1 )一定剂量 (2 5、50、1 0 0IU/mL)的HCG能显著抑制NK细胞的杀伤活性 ,其中以 50IU/mL的HCG作用最明显 ,而较低剂量 (1 2 .5IU/mL)和较高剂量 (2 0 0IU/mL)的HCG则无抑制作用。(2 )HCG对NK细胞的抑制作用通过单核细胞介导     

自配试剂在COULTER流式细胞仪检测NK细胞和B细胞中的应用

探讨美国COULTER流式细胞仪试剂国产化问题.将自配全血溶解试剂、鞘液及清洗液的理化性质、精密度、准确度、稳定性与原装试剂进行对比分析.分析结果显示自配试剂与原装试剂理化性质一致,采用自配试剂测定20份病人标本NK细胞和B细胞并与原装试剂对比,差异无统计学意义(P＞0.05),两者呈高度正相关r＞0.95.自配试剂稳定性好,放置1年后,与原装试剂分别测定15份标本,结果差异无统计学意义(P＞0.05),两者呈高度正相关r＞0.91,说明自配试剂完全可以代替美国COULTER流式细胞仪原装进口试剂进行NK细胞和B细胞的检测.     

A Monoclonal Antibody, DL10, Which Recognizes a Sugar Moiety of MHC Class I Antigens Expressed on NK Cells, NK+ T Cells, and Granulocytes in Humans

One mAb, DL10, was established from mice injected with dolphin lymphocytes. In addition to its reactivity against all dolphin lymphocytes, it reacted with some human leukocytes, including NK cells, NK⁺ T cells, and granulocytes. When its reactivity was examined in various animals, bovine, ovine, and equine leukocytes were DL10⁺. Murine, rat, and canine leukocytes were DL10^–. Although the reactivity of DL10⁺ was similar to those of CD56 and CD57 antigens in humans, the actual molecules it recognized were different. Thus, all reactivity of DL10 disappeared after treatment of cells with glycopeptidase or after culture of cells with tunicamycin. Furthermore, the immunoprecipitation method revealed that DL10 indirectly recognized the heavy chain (45kD) of MHC class I antigen in humans and animals. Considering data from analysis of the N-terminal amino acid sequence of the DL10 molecule and the HLA typing of reactive cells, DUO recognized a sugar moiety of some monomorphic MHC antigens and polymorphic MHC antigens such as HLA-B60 and -B61. If the donors are HLA-B60^– and -B61^– (>80% in Japan and >95% in the United States), DL10 would appear to be a very useful agent for the detection of pan-NK⁺ T cells.     

人外周血NK细胞在细胞因子刺激下扩增后穿孔素、颗粒酶B基因表达的变化

目的 探讨经过纯化及在多种细胞因子的作用下扩增后的NK细胞,其穿孔素(per-furin)、颗粒酶B(granzyme B)表达水平的改变与细胞杀伤率的关系.方法 应用竞争性定量RT-PCR方法 检测了8例供者纯化、扩增后NK细胞的穿孔素、颗粒酶B基因表达水平,同时检测其对K562细胞的杀伤率.结果 经纯化、扩增后的NK细胞,在多种细胞因子作用下穿孔素和颗粒酶B的基因表达水平明显提高,且.IL-2+IL-15组、IL-2+IL-12+IL-15组基因的表达量均显著高于其他组,NK细胞对K562的杀伤率结果 与基因表达水平一致.结论 应用细胞因子后可使NK细胞的穿孔素、颗粒酶B基因表达水平明显提高,同时提高了NK细胞的杀伤功能.     

Phenotype of NK Cells and Cytotoxic/Apoptotic Mediators Expression in Ectopic Pregnancy

Citation Laskarin G, Redzovic A, Vukelic P, Veljkovic D, Gulic T, Haller H, Rukavina D. Phenotype of NK cells and cytotoxic/apoptotic mediators expression in ectopic pregnancy. Am J Reprod Immunol 2010 Problem The expression of cytotoxic/apoptotic mediators and the phenotype characteristics of uterine NK cells (uNK) in tubal ectopic pregnancy (EP) were investigated. Method of study Samples of uterine decidua and tubal mucosa as well as peripheral blood (PB) of the same women with EP were used for phenotype characterization of NK cells and detection of cytotoxic/apoptotic mediators and IL‐15. Results In tubal mucosa, perforin, FasL, granulysin and IL‐15 were almost completely absent, but they were present in normal and EP uterine deciduas. TRAIL was present on trophoblast and tubal mucosa, contrary to its lack in normal and EP uterine decidua. CD16^?CD56^dim NK cells, mostly CD94^? and NKG2A^?, predominate in tubal mucosa, whereas CD16^?CD56^bright NK cells, predominantly CD94⁺ and NKG2A⁺ prevail in EP uterine decidua. NK cells at the EP implantation site express lower percentages of perforin and granulysin, but they express a higher percentage of TRAIL than do EP uterine decidual and PB NK cells. Lower percentage of TNF‐α‐expressing and IL‐4‐expressing NK cells were found at the implantation site compared to EP uterine decidua. Conclusions Authentic uNK cell population seems to be insufficient to restrict trophoblast invasion because of low expression of cytotoxic/apoptotic mediators.     

Single-Cell RNA Sequencing of Tumor-Infiltrating NK Cells Reveals that Inhibition of Transcription Factor HIF-1α Unleashes NK Cell Activity

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