人白血病细胞株重组激活基因表达及T细胞受体基因重排的检测

背景：淋巴细胞特异性重组激活基因编码的重组激活基因1与重组激活基因2蛋白是参与V（D）J重排机制的重要的重组酶。除参与V（D）J重排以外，近年的研究结果表明重组激活基因介导的转位作用可能与染色体易位及淋巴性恶性肿瘤的发生有关，但迄今尚未有明确定论。目的：检测重组激活基因、DNA修复因子Ku70／Ku80和末端脱氧核苷转移酶mRNA表达以及T细胞受体基因重排在人白血病和淋巴癌细胞株的发生情况。设计：重复测量实验。单位：南方医科大学生物技术学院分子免疫研究所。材料：T淋巴白血病细胞株Jurkat和6T-CEM购自上海细胞生物研究所；T淋巴白血病细胞株Molt-4，皮肤T细胞淋巴癌细胞株HuT102，Burkitt’s淋巴癌细胞株Raji和Daudi以及原髓细胞白血病细胞株HL-60和慢性髓原白血病细胞株K562均由本实验室保存。细胞用含有体积分数0．1胎牛血清的RPMI1640培养基于37℃，体积分数0．05C02条件下培养。方法：实验于2005-10／2006-01在南方医科大学生物技术学院分子免疫研究所完成。采用反转录聚合酶链反应检测重组激活基因1，重组激活基因2，非同源末端连接装置途径中的DNA修复因子Ku70／Ku80。以及末端脱氧核苷转移酶mRNA表达；采用巢式、半巢式聚合酶链反应、连接介导的聚合酶链反应等方法检测T细胞受体重排删除DNA环和T细胞受体B链重组信号序列两端的断裂点。了解参与V（D）J重排过程的基因表达和T细胞受体基因重排中间体的产生情况。主耍观察指标：重组激活基因、DNA修复因子Ku70／Ku80和末端脱氧核苷转移酶mRNA表达以及T细胞受体基因重排在人白血病和淋巴癌细胞株的发生情况。结果：反转录聚合酶链反应检测结果显示：重组激活基因1mRNA在4种T细胞株中均被检测到，在两种B细胞株和两种髓性白血病细胞株中未检测到；重组激活基因2和末端脱氧核苷转移酶mRNA表达仅在Jurkat，Molt-4和6T-CEM3种T细胞株中检测到，但在6T-CEM表达较弱；除HL-60细胞未检测到Ku80表达外，所有细胞株均检测到Ku70和Ku80表达。对4种T细胞株T细胞受体重排中间体检测结果表明：仅在Jurkat细胞中检测到DB2-J132 sjTRECs与DB25’端和3’Rss断点，表明Jurkat细胞发生T细胞受体基因重排。同时发现Jurkat TCR Dβ2-Jβ2重排删除环结合区具有明显的多样性特征。结论：重组激活基因可能与T细胞白血病具有更为密切的关系。Jurkat细胞有可能成为研究重组激活基因与T细胞淋巴性肿瘤的一个潜在的细胞模型。     

MTS1基因β启动子转录活性研究

目的 研究IMTSl基因β启动子在急性T淋巴细胞白血病细胞株中的转录激活情况，鉴定β启动子转录活性的功能片段区。方法 用DNA重组方法，构建MTS1基因口启动子3′端转录起始点相同，而5′端序列不同的7种pGL3重组质粒。用脂质体介导的基因瞬时转染法，将构建的重组质粒分别转染MTSl基因双等位缺失的Jurkat细胞株，检测pGL3重组质粒中荧光素酶报告基因的表达，观察β启动子在Jurkat细胞中的激活情况及其基础转录活性片段区。结果 成功构建了MTSI基因β启动子7种不同片段的重组质粒，它们在Jurkat细胞中均有转录活性，其中0．38kb Sac Ⅱ-Sac Ⅰ酶切片段是MTSl基因β启动子转录活性的基础片段。结论 IMTSlβ启动子可在Jurkat细胞中被激活。     

非霍奇金淋巴瘤细胞株中PTPL1的甲基化状态的研究

目的:探讨PTPL1基因启动子在非霍奇金淋巴瘤细胞株Hut78、Maver、Z138、CA46、Raji、Jurkat的甲基化状态及去甲基化药物阿扎胞苷对PTPL1基因转录调节的影响。方法:体外培养Hut78、Maver、Z138、CA46、Raji、Jurkat细胞株,采用甲基化特异性聚合酶链反应法(M S-PCR)检测PTPL1基因在各个细胞株中的甲基化状态,应用逆转录聚合酶链反应法(RT-PCR)检测PTPL1 mRNA在各个细胞株中的表达情况,采用CCK8方法检测不同浓度阿扎胞苷对细胞株增殖的抑制作用,探讨siRNA干扰PTPL1基因后对淋巴瘤细胞增殖的影响。结果:PTPL1基因启动子在Hut78,Maver,Z138细胞株中处于非甲基化状态,在细胞株Raji、CA46、Jurkat中处于高甲基化状态;PTPL1 mRNA在细胞株Hut78、M aver、Z138中处于不同水平的表达,而在细胞株Raji、CA46、Jurkat中PTPL1因高甲基化而失表达;去甲基化药物阿扎胞苷可抑制Raji、CA46和Jurkat细胞株的增殖并且可诱导PTPL1 mRNA的再表达;siRNA干扰PTPL1后淋巴瘤细胞生长得到促进。结论:PTPL1基因启动子高甲基化所致的基因沉默可能是非霍奇金淋巴瘤发生发展的一个重要因素,PTPL1基因的甲基化可作为一个良好的分子诊断标记及可能的治疗靶点。     

BIOMED-2多重聚合酶链反应检测抗原受体基因重排在淋巴增殖性疾病诊断中的应用

目的 建立敏感而有效的检测免疫球蛋白(Ig)和T细胞受体(TCR)基因重排的方法,并探讨在淋巴增殖性疾病诊断和鉴别中的作用.方法 采用BIOMED-2多重聚合酶链反应,检测来自54例淋巴增殖性疾病患者的58份淋巴组织标本,分析抗原受体基凶重排状况及其克隆来源.结果 在88.0%(25份标本中22份)B细胞淋巴瘤/白血病和53.3%(15份标本中8份)T细胞淋巴瘤中检出Ig/TCR呈单克隆重排;在17例淋巴组织非恶性增殖患者的病理活检标本中,14例(82.4%)呈多克隆重排;在合格的57份标本中有44份(77.2%)的结果与最终诊断相符.联合检测Igλ和TCRδ并未提高Ig/TCR单克隆重排的检出率,但可能有助于Igλ和TCRδ+淋巴瘤的诊断.结论 对于分析淋巴增殖性疾病,尤其是不典型病例的克隆来源状况,BIOMED-2多重聚合酶链反应检测抗原受体基凶重排是迅速、敏感而可靠的方法.     

聚合酶链反应扩增T细胞受体β基因重排在检测T细胞淋巴瘤克隆中的应用

聚合酶链反应扩增Ｔ细胞受体β基因重排在检测Ｔ细胞淋巴瘤克隆中的应用余英豪，朱梅刚，季卉，赵彤，张素娟，吴秋良我们采用聚合酶链反应（ＰＣＲ）技术检测新鲜及石蜡组织Ｔ细胞受体（ＴＣＲ）基因重排均获得成功，现将初步结果报道如下。材料和方法新鲜淋巴结标本２９...     

硼替佐米对淋巴瘤细胞增殖、凋亡及SHP-2基因表达的影响

目的:研究硼替佐米对淋巴瘤细胞株Jurkat细胞和Raji细胞的增殖、凋亡及SHP-2基因表达的影响。方法:用MTT(噻唑蓝)实验观察不同浓度硼替佐米对Jurkat细胞和Raji细胞增殖的作用;利用细胞形态学检查、流式细胞仪检测细胞凋亡;用RT-PCR的方法检测硼替佐米处理淋巴瘤细胞株前后SHP-2基因的mRNA表达水平。结果:硼替佐米对Jurkat细胞和Raji细胞有抑制增殖,诱导凋亡的作用,并呈剂量和时间依赖性。在5-100 nmol/L硼替佐米处理后,Jurkat细胞株和Raji细胞株中SHP-2 mRNA的表达水平上调。结论:硼替佐米明显抑制Jurkat细胞株和Raji细胞株增殖,诱导其凋亡,上调细胞株SHP-2 mRNA的表达水平,表明SHP-2基因很可能参与了硼替佐米诱导Raji细胞和Jurkat细胞凋亡的调控。     

T细胞受体γδ基因重排

现在已广泛用分析免疫球蛋白(Ig)和T细胞受体(TCR)基因重排,了解淋巴细胞发育规律,临床上也用来检测恶性淋巴增殖性疾病.较早发现的TCR是TCRα和β,出现在大部分成熟T细胞的表面,负责抗原识别,受多种MHC基因产物的限制.TCR与CD3结合在一起,是最重要的传导信号的受体.最近,另外一对TCR受体基因TCRγδ也逐渐清楚了.几乎所有T细胞表现都会有αβ或γδ表达.TCRγ和δ基因在胸腺发育早期重排,然后才有TCRα或β重排.现在还不知道TCRγδ的全部作用,有人认为与T细胞激活有关.激活的γδ表达细胞有不依赖MHC的细胞毒活性.     

11β-羟类固醇脱氢酶2在恶性淋巴细胞中的表达及与其对糖皮质激素敏感性关系

本研究讨论11β-羟类固醇脱氢酶2(11β-HSD2)在3种来源淋巴的细胞系中的表达及其与恶性淋巴细胞对糖皮质激素敏感性的关系.利用实时定量PCR及Western blot方法检测急性淋巴细胞白血病Jurkat细胞系、淋巴瘤Daudi和Raji细胞系、以及健康志愿者外周血T淋巴细胞中11β-HSD2的表达;用流式细胞术...     

β-连环素在白血病细胞株的异常定位研究

β-连环素是Wnt信号通路关键的信号传递子，其在细胞的异常定位引起下游靶基因的转录是多种实体肿瘤发生的原因之一。由于造血细胞缺少典型的黏着连接（adherens junction，AJ），因此对β-连环素在血液肿瘤的表达及定位并无较多的研究。本研究探讨4种常见的白血病细胞株（Daudi，Jurkat，K562和Thp-1）中β-连环素蛋白的定位及β-连环素基因mRNA的表达水平，了解血液肿瘤中是否有β-连环素蛋白的定位异常，以期发现白血病新的发生机制，为寻找新的特异治疗靶点提供线索。用免疫细胞化学法检测β-连环素在白血病细胞系中的定位，用实时定量RT-PCR法测定β-连环素mRNA表达水平。结果表明：4种白血病细胞株有两种（Jurkat、Thp-1）存在β-连环素的异常定位，且β-连环素mRNA表达增高，但在Jurkat和Thp-1细胞中的β-连环素mRNA低于Daudi和K562细胞。这4种白血病细胞株中β-连环素基因的mRNA表达水平与其异常定位无相关性。结论：β-连环素定位异常可能参与部分血液肿瘤的发生，引起β-连环素定位异常的机制并不是发生在转录水平。     

As_2O_3对Jurkat细胞株hdpr1基因去甲基化作用机制的研究

本研究探讨三氧化二砷（arsenic trioxide,As2O3）对急性T淋巴细胞白血病Jurkat细胞株hdpr1抑癌基因去甲基化的影响及其作用机制。采用CCK8法检测As2O3对Jurkat细胞的增殖抑制作用,流式细胞术检测As2O3作用前后细胞周期的变化,甲基化特异性PCR（MSP）检测As2O3对hdpr1基因甲基化模式的影响,用半定量RT-PCR检测As2O3对hdpr1基因、DNA甲基转移酶基因dnmt1、dnmt3a、dnmt3b mRNA表达水平的影响。结果表明：As2O3可明显抑制Jurkat细胞的增殖并呈时间-浓度依赖性;As2O3阻滞Jurkat细胞周期于G0/G1期（p〈0.05）,呈浓度依赖性;As2O3能够逆转Jurkat细胞株hdpr1基因的高甲基化并诱导其mRNA重新表达,同时下调dnmt1、dnmt3a、dnmt3b mRNA的表达水平,亦呈浓度依赖性。结论：As2O3抑制Jurkat细胞的增殖,阻滞细胞周期于G0/G1期,其机制可能为下调dnmt1、dnmt3a、dnmt3b基因的表达,诱导Jurkat细胞中异常甲基化的hdpr1基因去甲基化并使其恢复表达。     

Rearrangements of immunoglobulin and T cell receptor beta and gamma genes are associated with terminal deoxynucleotidyl transferase expression in acute myeloid leukemia

The cell origin of the rare terminal deoxynucleotidyl transferase (TdT)-positive acute myeloid leukemias (AML) was investigated at the molecular level, by examining the configuration of the Ig H (Igh) and L (Ig kappa, Ig lambda) chain gene regions, and of the T cell receptor (TCR) beta and T cell rearranging (TRG) gamma loci. In 8 of the 10 TdT+ AML analyzed (classified as myeloid according to morphological and cytochemical criteria, and to the reactivity with one or more antimyeloid mAbs), a rearrangement of the Igh chain gene was found. In TdT- AML, evidence of an Igh gene reorganization was instead observed only in 2 of the 42 patients studied. Furthermore, evidence of TCR-beta and/or TRG-gamma gene rearrangement was observed in four AML, all of which belonged to the Igh-rearranged TdT+ group. In three cases (one TdT+ and two TdT-), the Ig kappa L chain gene was also in a rearranged position. These findings demonstrate a highly significant correlation between TdT expression and DNA rearrangements at the Igh and TCR chain gene regions and support the view that this enzyme plays an important role in the V-(D)-J recombination machinery. Overall, the genomic configuration, i.e., JH gene rearrangement sometimes coupled to a kappa L chain and TCR gene reorganization, similar to that found in non-T-ALL, suggests that in most cases of TdT+ AML, the neoplastic clone, despite the expression of myeloid-related features, is characterized by cells molecularly committed along the B cell lineage.     

A variant of SCID with specific immune responses and predominance of gamma delta T cells

We describe here a patient with a clinical and molecular diagnosis of recombinase activating gene 1-deficient (RAG1-deficient) SCID, who produced specific antibodies despite minimal B cell numbers. Memory B cells were detected and antibodies were produced not only against some vaccines and infections, but also against autoantigens. The patient had severely reduced levels of oligoclonal T cells expressing the alphabeta TCR but surprisingly normal numbers of T cells expressing the gammadelta TCR. Analysis at a clonal level and TCR complementarity-determining region-3 spectratyping for gammadelta T cells revealed a diversified oligoclonal repertoire with predominance of cells expressing a gamma4-delta3 TCR. Several gammadelta T cell clones displayed reactivity against CMV-infected cells. These observations are compatible with 2 non-mutually exclusive explanations for the gammadelta T cell predominance: a developmental advantage and infection-triggered, antigen-driven peripheral expansion. The patient carried the homozygous hypomorphic R561H RAG1 mutation leading to reduced V(D)J recombination but lacked all clinical features characteristic of Omenn syndrome. This report describes a new phenotype of RAG deficiency and shows that the ability to form specific antibodies does not exclude the diagnosis of SCID.     

9例γδT细胞淋巴瘤/白血病患者的临床及实验室特征

目的 报告9例γδ T细胞淋巴瘤/白血病患者的临床及实验室特征.方法 对2007至2010年住院诊治的患者,常规询问病史,进行体检及实验室检测.对有异常细胞的骨髓或脾组织用流式细胞分析技术(FCM)行免疫分型,同时用PCR法检测TCRγ、TCRδ基因克隆性重排,用G显带技术分析染色体,用多重筑巢式PCR技术筛查急性白血病基因及1-8型人类疱疹病毒基因,并行形态学及细胞化学染色.根据表达TCRγδ链来确定γδT细胞,根据T细胞抗原表达异常确定恶性γδT细胞,根据γδT细胞表达CD34、CD99、TDT、CD1a及急性白血病基因等确定为前体γδT细胞.结果 共9例患者经FCM分析诊断为γδT细胞淋巴瘤/白血病,初诊时8例患者骨髓中检测出大量恶性细胞,细胞形态同原始细胞.5例患者诊断为急性T淋巴细胞白血病(T-ALL)或淋巴母细胞淋巴瘤(LBL)(γδT型),4例患者诊断为肝脾γδT细胞淋巴瘤(HSγδTCL).行TCR基因克隆重排检测的6例患者均检测出有克隆性TCRγ和(或)TCRδ基因重排.全部患者化疗难以完全缓解(CR)或CR后很快复发,5例接受异基因造血干细胞移植(allo-HSCT)的患者4例持续CR,CR时间分别为2、2、3、12个月;1例TALL(γδT型)患者在allo-HSCT后1个月内复发.结论 γδT细胞淋巴瘤/白血病的发病率可能比既往报道的高,部分T-ALL/LBL也为γδT细胞型;FCM是快速可靠的诊断方法,克隆性TCRγ和(或)TCRδ基因重排阳性有助于诊断;患者预后差,allo-HSCT可能是唯一可治愈的方法.

Abstract：

Objective To analyze the clinical and laboratory features of 9 cases of γδT cell lymphoma or leukemia.Methods From 2007 to 2011, 9 patients with γδT-cell lymphoma/leukemia were diagnosed in our hospital.The immunophenotype of the abnormal cells were detected by flow cytometry, clonal gene rearrangement of IgH,TCRγ,TCRδ by PCR, chromosome karyotype analysis by G banding, acute leukemia gene and the DNA of type 1-8 human herpes virus by mulplex nested PCR, The γδT cells were determined by T cell with TCR γδ chain, the malignant γδ T cells by the abnormal expression of T cell antigens and the precursor malignant γδ T cells by the expression of CD34, TDT ,CD99, CD1a or acute leukemia genes.Results In the 9 patients with γδT cell lymphoma leukemia, significant malignantγδT cells infiltration of bone marrow were found in 8 with blast morphology.5 were diagnosed as T-ALL/LBL(γδT type) and 4 HSγδ TCL.The clonal gene rearrangement of TCRγ and/or TCRδ were detected in 6/6 patients.Patients either did not achieve complete remission (CR) after induction therapy or relapsed quickly after CR.Only 4/5 patients remained continuous CR(CCR) at 2,2,3,12 months respectively, after allogeneic hematopoietic stem cell transplantation(allo-HSCT), the fifth T-ALL(γδT) relapsed 1 month after allo-HSCT .Conclusion s The incidence of γδ T cell lymphoma or leukemia may be higher than reported, part of them were T-ALL/LBL with poor prognoses.FCM and clonal gene rearrangement of TCRγ and/or TCRδ are helpful to diagnosis.Allo-HSCT may be the only curative approach.     

The role of recombination activating gene (RAG) reinduction in thymocyte development in vivo

Assembly of T cell receptor (TCR)alpha/beta genes by variable/diversity/joining (V[D]J) rearrangement is an ordered process beginning with recombination activating gene (RAG) expression and TCRbeta recombination in CD4(-)CD8(-)CD25(+) thymocytes. In these cells, TCRbeta expression leads to clonal expansion, RAG downregulation, and TCRbeta allelic exclusion. At the subsequent CD4(+)CD8(+) stage, RAG expression is reinduced and V(D)J recombination is initiated at the TCRalpha locus. This second wave of RAG expression is terminated upon expression of a positively selected alpha/beta TCR. To examine the physiologic role of the second wave of RAG expression, we analyzed mice that cannot reinduce RAG expression in CD4(+)CD8(+) T cells because the transgenic locus that directs RAG1 and RAG2 expression in these mice is missing a distal regulatory element essential for reinduction. In the absence of RAG reinduction we find normal numbers of CD4(+)CD8(+) cells but a 50-70% reduction in the number of mature CD4(+)CD8(-) and CD4(-)CD8(+) thymocytes. TCRalpha rearrangement is restricted to the 5' end of the Jalpha cluster and there is little apparent secondary TCRalpha recombination. Comparison of the TCRalpha genes expressed in wild-type or mutant mice shows that 65% of all alpha/beta T cells carry receptors that are normally assembled by secondary TCRalpha rearrangement. We conclude that RAG reinduction in CD4(+)CD8(+) thymocytes is not required for initial TCRalpha recombination but is essential for secondary TCRalpha recombination and that the majority of TCRalpha chains expressed in mature T cells are products of secondary recombination.     

Ku70 Is Required for DNA Repair but Not for T Cell Antigen Receptor Gene Recombination In Vivo

Ku is a complex of two proteins, Ku70 and Ku80, and functions as a heterodimer to bind DNA double-strand breaks (DSB) and activate DNA-dependent protein kinase. The role of the Ku70 subunit in DNA DSB repair, hypersensitivity to ionizing radiation, and V(D)J recombination was examined in mice that lack Ku70 (Ku70^−/−). Like Ku80^−/− mice, Ku70^−/− mice showed a profound deficiency in DNA DSB repair and were proportional dwarfs. Surprisingly, in contrast to Ku80^−/− mice in which both T and B lymphocyte development were arrested at an early stage, lack of Ku70 was compatible with T cell receptor gene recombination and the development of mature CD4⁺CD8⁻ and CD4⁻CD8⁺ T cells. Our data shows, for the first time, that Ku70 plays an essential role in DNA DSB repair, but is not required for TCR V(D)J recombination. These results suggest that distinct but overlapping repair pathways may mediate DNA DSB repair and V(D)J recombination.     

New insights on human T cell development by quantitative T cell receptor gene rearrangement studies and gene expression profiling

To gain more insight into initiation and regulation of T cell receptor (TCR) gene rearrangement during human T cell development, we analyzed TCR gene rearrangements by quantitative PCR analysis in nine consecutive T cell developmental stages, including CD34+ lin- cord blood cells as a reference. The same stages were used for gene expression profiling using DNA microarrays. We show that TCR loci rearrange in a highly ordered way (TCRD-TCRG-TCRB-TCRA) and that the initiating Ddelta2-Ddelta3 rearrangement occurs at the most immature CD34+CD38-CD1a- stage. TCRB rearrangement starts at the CD34+CD38+CD1a- stage and complete in-frame TCRB rearrangements were first detected in the immature single positive stage. TCRB rearrangement data together with the PTCRA (pTalpha) expression pattern show that human TCRbeta-selection occurs at the CD34+CD38+CD1a+ stage. By combining the TCR rearrangement data with gene expression data, we identified candidate factors for the initiation/regulation of TCR recombination. Our data demonstrate that a number of key events occur earlier than assumed previously; therefore, human T cell development is much more similar to murine T cell development than reported before.     

Reconstitution of T cell receptor signaling in ZAP-70-deficient cells by retroviral transduction of the ZAP-70 gene

A variant of severe combined immunodeficiency syndrome (SCID) with a selective inability to produce CD8 single positive T cells and a signal transduction defect in peripheral CD4+ cells has recently been shown to be the result of mutations in the ZAP-70 gene. T cell receptor (TCR) signaling requires the association of the ZAP-70 protein tyrosine kinase with the TCR complex. Human T cell leukemia virus type I- transformed CD4+ T cell lines were established from ZAP-70-deficient patients and normal controls. ZAP-70 was expressed and appropriately phosphorylated in normal T cell lines after TCR engagement, but was not detected in T cell lines from ZAP-70-deficient patients. To determine whether signaling could be reconstituted, wild-type ZAP-70 was introduced into deficient cells with a ZAP-70 retroviral vector. High titer producer clones expressing ZAP-70 were generated in the Gibbon ape leukemia virus packaging line PG13. After transduction, ZAP-70 was detected at levels equivalent to those observed in normal cells, and was appropriately phosphorylated on tyrosine after receptor engagement. The kinase activity of ZAP-70 in the reconstituted cells was also appropriately upregulated by receptor aggregation. Moreover, normal and transduced cells, but not ZAP-70-deficient cells, were able to mobilize calcium after receptor ligation, indicating that proximal TCR signaling was reconstituted. These results indicate that this form of SCID may be corrected by gene therapy.