Stable clonal expansion of the T-cell receptor Vβ6， Vβ17 and Vβ19 T cells in a cGVHD case using genescan analysis

Objective To investigate the distribution and clonality of the T-cell receptor (TCR) Vβ repertoire in chronic graft versus host disease (cGVHD).Methods The complementarity determining region 3 (CDR3) of the TCRβ gene with 24 variab le regions was amplified in peripheral blood mononuclear cells drawn from one cG VHD patient after allogenic bone marrow transplantation (allo-BMT) 35, 39, 43 o r 45 months respectively, using RT-PCR, to observe the expression of TCR Vβ re pertoire T cells.The PCR products were further analyzed by genescan to evaluat e clonality of T cells.Results Fourteen or 16 TCR Vβ subfamily T cells were detected in each sample of cGVHD c ase. Oligoclonal T cells were identified in TCR Vβ 6, 16, 17, 19 and 21 subfamili es.The stable clonal T cells in all samples were identified in Vβ6, Vβ17 and Vβ21 subfamilies. Conclusion Skewing distribution and stable clonal expansion of T cells can be found in cG VHD cases and it may be related to the initiation of cGVHD.     

Changes in the T-cell receptor Vβ gene repertoire after allogeneic hematopoietic stem cell transplantation

Background We distinguished graft-versus-host disease (GVHD) from graft-versus-leukemia (GVL) effects and to investigate the distribution of T-cell receptor (TCR) Vβ gene repertoire in individuals with leukemia before and after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods Peripheral blood mononuclear cells (PBMC) were obtained from 10 normal individuals, 8 donors and 11 patients with leukemia before and after transplantation. Polymerase chain reaction (PCR) amplification of complementarity-determining region 3 (CDR3) of 24 TCR Vβ genes was used to examine serial samples of PBMC. The PCR products were further analyzed by genescan to evaluate clonality of T cells. Results The 24 TCR Vβ gene repertoire displayed highly diverse and polyclonal spectratypes in all normal individuals and 4 of 8 donors. Another 4 donors expressed part of the 24 TCR V~ subfamily and 1 donor had oligoclonality. The expressions of the 24 TCR V~ subfamilies were skewed and restricted in 11 leukemia patients before and after transplantation. Some absences of 24 TCR Vβ subfamily expression were quite similar between the recipients pro-transplantation and related donors. The number of subfamilies expressed increased over time post-transplantation, but the restricted expressions of the subfamily could last 6-30 months after transplantation. All patients with GVHD and some without GVHD exhibited T cell clonal expansion. The expansive T cell clone was distributed in Vβ 2-3, 16-17, 18-19, 21 and Vβ 23 in patients with GVHD and in Vβ 7, 9, 16 and 19 in patients without GVHD. One patient with syngeneic-HSCT (syn-HSCT) had Vβ 15 and 16 T cell expansion after transplantation. One patient displayed Vβ 18 T cell expansion after donor lymphocyte infusion (DLI). Conclusions Normal individuals express the entire 24 TCR Vβ gene repertoire and have polyclonal distribution. However, the TCR Vβ gene repertoire is only partially expressed in some donors. The TCR Vβ gene repertoire is restrictedly expressed in a skew fashion in patients with leukemia before and after transplantation. The number of TCR Vβ gene subfamilies increases over time posttransplantation. GVHD and GVL effects may induce the proliferation of T cell clones. Clinical GVL response may be distinguished from GVHD alloreactivity through the host MHC antigen.     

Expression of recombination-activating genes and T cell receptor gene recombination in the human T cell leukemia cell line

Background Recent studies have suggested that mature T cells can change their specificity through reexpression of recombination-activating genes （RAG） and RAG-mediated V（D）J recombination. This process is named receptor revision and has been observed in mature peripheral T cells from transgenic mice and human donors. However, whether the receptor revision in mature T cells is a random or orientated process remains poorly understood. Here we used the Jurkat human T cell line, which represents a mature stage of T cell development, as a model to investigate the regulation of T cell receptor （TCR） gene recombination. Methods TCR Dβ-Jβ signal joint T cell receptor excision DNA circles （sjTRECs） were determined by nested and seminested PCR. Double-strand DNA breaks at recombination signal sequences （RSSs） in the TCRVβ chain locus were detected by ligation-mediated-PCR. Further analysis of the complementarity-determining region 3 （CDR3） size of the TCRVβ chain was examined by the TCR GeneScan technique. Results RAG1, RAG2, and three crucial components of the nonhomologous DNA end-joining （NHEJ） pathway were readily detected in Jurkat. Characteristics of junctional diversity of Dβ2-Jβ2 signal joints and ds RSS breaks associated with the Dβ2 5＇ and Dβ 2 3＇ sites were detected in DNA from Jurkat cells. CDR3 size and the gene sequences of the TCRVβ chain did not change during cell proliferation. Conclusions RAG1 and RAG2 and ongoing TCR gene recombination are coexpressed in Jurkat cells, but the ongoing recombination process may not play a role in modification of the TCR repertoire.However, the results suggest that Jurkat could be used as a model for studying the regulation of RAGs and V（D）J recombination and as a ＂special＂ model of the coexistence of TCR gene rearrangements and ＂negative＂ receptor revision.     

Analysis of the T cell receptor Vδ region gene repertoire in bronchoalveolar lavage fluid (BALF) and peripheral blood of asthmatics

Objective To explore the role of γδT cells in the airway of asthmatics and to identify t he forces which induce and maintain the inflammatory process.Methods Peripheral blood (PB) and bronchoalveolar lavage fluid (BALF) were obtained from 7 asthmatic subjects and 7 nonsmoker control subjects. The percentage of γδT cells in the PB and BALF was measured by immunofluorescent staining and flow cy tometry. The frequency of usage and the clonality of Vδ subfamilies (Vδ(1)-V δ(3)) were assessed by RT- PCR and gene scanning. Results A higher proportion of γδT cell was detected in the BALF of asthmatic subjects (7.8%±4.7%) than that from control subjects (3.3%±3.0%, P=0.04). No selective usage for a particular Vδ subfamily was found, but the relative ex pression level of Vδ(1) was significantly higher in the asthmatic airway (44%± 13%) than in the control (19%±5%, P=0.0002). In asthmatic subjects, the m onoclonal or oligoclonal expansion of γδT lymphocytes was predominant in the B ALF, especially Vδ(1)(+) T lymphocytes.Conclusions Antigenic specific γδT cells might play an important role in the inducement an d maintenance of airway inflammation. Persistent antigenic stimulation may be t he key factor that maintains chronic airway inflammation in asthma.     

Role of T-cell receptor V beta 8.3 peptide vaccine in the prevention of experimental autoimmune uveoretinitis

Background T-cell receptor （TCR） plays an important role in the development of autoimmune diseases. Recently, it was reported that immunization of animals with TCR peptide derived from the pathogenic cells could prevent autoimmune diseases. The aim of this study was to investigate whether vaccination with a synthetic peptide from the hypervariable region of TCR Vβ 8.3, an experimental autoimmune uveoretinitis （EAU）-associated gene, was able to prevent the disease. Methods EAU was induced in Lewis rats by immunization with IRBP R16 peptide emulsified in complete Freund＇s adjuvant （CFA）. The clinical and histological appearances were scored. Delayed type hypersensitivity （DTH） and lymphocyte proliferation were detected. Cytokine levels of aqueous humour, supernatants of cells from spleen and draining lymph nodes were measured by enzyme linked immunosorbent assay （ELISA）. Gene expression of TCR Vβ8.3 on CD4^＋ T cells was examined by real time quantitative polymerase chain reaction （PCR）. Results After vaccination, the intraocular inflammation was significantly mitigated, antigen specific DTH and lymphocyte proliferation responses were suppressed, interleukin （IL）-2 in aqueous humour, interferon （IFN）-γ and IL-2 produced by the spleen and draining lymph node cells were significantly decreased, whereas the production of IL-4 and IL-10 were increased. The response of draining lymph node cells to TCR Vβ 8.3 peptide was enhanced after vaccination. Inoculation with CFA alone did not affect the severity of EAU and the above parameters. The suppression of EAU was much stronger in the group of four fold inoculations than the group of two fold inoculations. The expression of TCR Vβ 8.3 gene was significantly reduced in the group of fourfold inoculations. Conclusion Vaccination with the synthetic TCR Vβ 8.3 peptide could remarkably inhibit the development of EAU.     

Serum- free culture of dendritic cells from patients with chronic myeloid leukemia in vitro and estimation of their cytotoxicity

Objective To establish a serum- free culture system of dendritic cells (DCs) from chronic myeloid leukemia (CML) cells so that DCs vaccine may be applied to the adoptive immunotherapy of CML in the near future.Methods Fetal calf serum, serum- free medium and autologous serum were used for culture of DCs. The usage of cytokines was classified into two groups: group A (stem cell factor, granulocyte/macrophage colony- stimulating- factor, tumor necrosis factor- α and interleukin- 4) and group B (granulocyte/macrophage colony- stimulating- factor, tumor necrosis factor- α and interleukin- 4). The phenotypes of DCs were analyzed by using indirect immunofluorescence and flow cytometry. Mixed leukocyte responses were performed by methyl thiazolyl tetrazolium (MTT) assay. Chromosome analysis of DCs can be achieved by displaying G banding. T cells from CML patients were stimulated with autologous DCs and T- cell cytotoxicity was measured by (MTT) assay. Results CD34(+) cells or mononuclear cells were obtained from peripheral blood or bone marrow samples of eight patients of chronic- phase CML. Group A of serum- free medium was better than group B in expansion of total cell numbers and the rate of DCs. These results of serum- free medium were not significantly different from those of fetal calf serum medium, but the results of autologous serum medium were inferior to two groups above. The expression of major histocompatibility complex class Ⅱ antigen on the surface of DCs was notable (＞50%), but the expression of CD83 and the costimulatory molecules CD86 was not noticeable (10%-50%). Although CD1a+/CD14- DCs were potent stimulators of allogeneic lymphocytes, expansion of T cells from normal volunteers were not significant (average 27. 2 fold at DCs∶T cells ratio of 1∶10). At day 12, CD1a+ cells from three patients were studied by displaying G banding and Ph+ cells in these populations were 100%, 98% and 60%, respectively. At an effector∶target ratio of 40∶1, 32% to 45% cytotoxicity was noted with DC- stimulated T cells against autologous leukemia cells. Conclusions A stable serum- free culture system of CML- DCs was established. The expression of CD83 and CD86 on the surface of CML- DCs and DCs’ potent stimulation of allogeneic lymphocytes were not notable. DCs in CML patients can be derived from the malignant clone and these malignant DCs could induce anti- leukemic reactivity in autologous T lymphocytes without the necessity for additional exogenous antigens.     

Different methylation patterns of the M-BCR gene in myeloblastic and lymphoblastic crisis of chronic myelocytic leukemia.

OBJECTIVE To investigate the relationship between methylation status of M-bcr gene and transformation of chronic myelocytic leukemia (CML) from chronic to blastic phase.

METHODS The methylation patterns of M-bcr in 23 patients with Ph' positive CML were studied. DNAs extracted from mononuclear cells of both chronic and blastic phases (20 cases) or blastic phases only (3 cases), were doubly digested with restriction enzymes HpaII and BglII, hybridized with a 5'M-bcr probe labeled with 32p-deoxycytidine triphosphate, and autoradiographed.

RESULTS In all the patients with myeloblastic crisis, DNAs from both chronic and blastic cells of each patient showed identical methylation patterns. There was substantial heterogeneity in methylation patterns in the patients with lymphoblastic crisis. All the lymphoblastic patterns were distinct from the chronic patterns as well as the patterns shown in myeloblastic crisis. Moreover, in four out of six patients with lymphoblastic crisis, the chronic patterns were different from those in cases with myeloblastic crisis.

CONCLUSIONS The methylation status of M-bcr was stable during evolution of CML from chronic to myeloblastic phase. Analysis of M-bcr methylation status may be of clinical use in distinguishing lymphoblastic from myeloblastic crisis and predicting the cell lineage of crisis when the disease is still in its chronic phase.

     

CML患者外周血TCR Vδ亚家族T细胞的谱系变化研究

目的 了解慢性粒细胞白血病(chronic myeloid leukemia,CML)患者慢性期(chronic phase,CP)和缓解期(complete remission,CR)外周血T细胞受体(T cell receptor,TCR)Vδ亚家族T细胞的分布和克隆性情况.方法 利用RT-PCR扩增8例CML-CP和8例CML-CR患者外周血T细胞中8个Vδ亚家族基因的互补决定区(CDR3),了解TCR Vδ亚家族T细胞的分布和利用情况;阳性产物进一步经基因扫描分析CDR3长度,从而了解其克隆性.10例健康人外周血作为对照.结果 8例CML-CP患者外周血T细胞平均表达(3.25±0.89)个Vδ亚家族,主要以Vδ1、Vδ2和Vδ3的表达为主,而8例CR期患者则平均表达(3.50±0.76)个Vδ亚家族,主要集中在Vδ1、Vδ2、Vδ3和Vδ8中表达;两组与健康对照组(3.50±0.52)比较无统计学意义.此外,Vδ8表达频率在CML-CR患者(5/8)中略高于健康人(3/10)和CML-CP患者(2/8).基因扫描绝大多数患者和健康人外周血TCR Vδ亚家族T细胞均存在克隆性增殖现象,主要以Vδ1-Vδ3为主,但在CML-CR患者中,表达V87亚家族的两例样本均呈克隆性增殖,这在10例健康人中均未检测到.结论 3组样本的外周血T细胞中TCR Vδ谱系和克隆性增殖类似,提示CML患者T细胞免疫抑制可能并不主要累及TCR Vδ谱系变化,并在CML-CR期所出现了一些不同的Vδ表达和克隆模式.     

CML患者外周血TCR Vγ亚家族T细胞的谱系变化研究

目的 探讨慢性粒细胞白血病（CML）慢性期（CP）和缓解期（CR）病人外周血T细胞中T细胞受体（TCR）Vγ基因谱系的分布和克隆性情况。方法 利用RT-PCR检测8例CML-CP和8例CML-CR病人外周血T细胞3个TCR Vγ亚家族的表达,了解TCR Vγ亚家族T细胞的分布和利用情况;阳性产物进一步经荧光素标记和基因扫描分析CDR3长度,从而了解其克隆性。10例健康成人外周血作为对照。 结果 8例CP期和8例CR期的CML病人外周血T细胞分别平均表达（1.88±0.64,2.13±0.83）个亚家族,两者比较尚无统计学差异,但均明显低于健康对照组（P=0.000,P=0.036）。CP和CR期病人TCR VγⅢ的表达率明显低于健康对照组（2.9±0.32）（P=0.013,P=0.043）,基因扫描显示CML-CP 和CML-CR出现克隆模式的改变主要集中在TCR VγⅡ亚家族。结论 CP期病人外周血 TCR Vγ基因谱系出现限制性利用和克隆性增殖T细胞,主要可能与病人处于细胞免疫抑制状态有关,即使CR期病人其T细胞仍处于一定程度的免疫抑制状态。     

基因扫描分析一例cGVHD病人稳定性克隆性扩增的TCR Vβ6，Vβ17和Vβ19T细胞

目的　分析慢性移植物抗宿主病 (cGVHD)中TCRVβ谱系的分布和克隆性。方法　应用RT PCR扩增一例CML异基因骨髓移植后cGVHD病人第 35,39,4 3和 4 5个月的外周血单个核细胞的TCRVβ 2 4个亚家族的CDR3,了解病人TCRVβT细胞的表达 ,PCR产物进一步经基因扫描分析确定T细胞克隆性。结果　cGVHD病人每个标本存在 14 16个Vβ家族T细胞 ;寡克隆T细胞可见于Vβ6 ,16 ,17,19和 2 1亚家族 ,稳定性克隆性TCRVβ6、17和 2 1T细胞可见于全部标本。结论　cGVHD病人存在倾斜性分布和克隆性生长T细胞 ,它可能与cGVHD的发生有关     

应用RT—PCR和基因扫描分析TCR Vβ谱系的CDR3长度了解急性单核细胞白血病病人克隆性增殖T细胞

目的：了解急性单核细胞白血病（AML-M5）病人TCR Vβ亚家族T细胞的分布及其克隆性。方法：利用RT-PCR分别扩增9例M5病人外周血单个核细胞的TCR Vβ24个亚家族基因的CDR3,了解TCR Vβ谱系的表达情况。PCR 产物进一步经基因扫描分析,确定T细胞克隆性。结果：9例AML-M5病人仅存在1-10个Vβ亚家族T细胞,而正常血标本则可检测到24个Vβ亚家族。基因扫描分析显示：8例病人的某些Vβ亚家族出现这一主峰图象（寡克隆性T细胞）。Vβ2寡克隆T细胞发现于6例病人中。结论：结果提示AML-M5病人存在克隆性增殖的T细胞,主要为Vβ2亚家族,推测这可能是对白血病细胞（M5）相关抗原的特异性免疫反应并可能具有抗白血病的活性。     

结直肠癌患者外周血呈现T细胞寡克隆增殖

目的:通过结直肠癌患者术前外周血T淋巴细胞的T细胞受体(TCRβ)基因谱型,了解肿瘤患者外周血中T细胞克隆特征以及机体抗肿瘤免疫状况.方法: 采用RT-PCR方法扩增结直肠癌患者术前外周血、肿瘤组织和术后外周血TCRβ基因的24个V基因片段,经过特殊的测序凝胶分离和银染色后,确定它们的TCRβV基因表达谱型.通过PCR产物直接测序的方法,分析克隆性增殖的特征和CDR3区氨基酸序列.结果: 结直肠癌患者术前外周血的TCRβ基因谱型中具有克隆性表达条带,其中有些克隆的CDR3区与肿瘤组织肿瘤浸润性淋巴细胞(tumor infiltrating lymphocyte,TIL)中克隆性表达的TCRβ基因的CDR3区具有相同的氨基酸基序;临床特征表现为肿瘤局部有淋巴结转移,但是术后10个月没有复发.结论: 结直肠癌患者外周血具有与肿瘤负荷相关的T淋巴细胞克隆性增生,可能是肿瘤相关抗原特异性的抗肿瘤T淋巴细胞克隆.     

KG1a细胞体外诱导人外周血T细胞杀伤活性和TCR Vβ T细胞增殖的研究

【摘　要】　目的　了解急性髓系白血病KG1a细胞体外诱导人外周血T细胞的特异性细胞毒作用和T细胞受体(TCR) Vβ谱系表达和克隆性情况。方法　分别以Jurkat和Raji细胞作为阳性和阴性对照，建立TCR Vβ谱基因扫描技术，并用其检测5例健康个体T细胞克隆表型。采用混合淋巴细胞/肿瘤细胞培养方法，以照射后的KG1a细胞作为刺激原体外诱导外周血单个核细胞增殖，应用LDH释放法检测不同效靶比时诱导前后T细胞杀伤KG1a细胞的活性，同时利用基因扫描技术分析诱导后TCR Vβ亚家族的克隆性增殖特点。结果　基因扫描显示5例健康人全部TCR Vβ谱型均呈高斯(钟型)分布，各亚家族表达频率接近，但呈现不同的多态性和长度分布。KG1a细胞可以诱导出呈单克隆、寡克隆或寡克隆趋势生长的亚家族T细胞，并具有特异性识别和杀伤KG1a细胞的功能。结论　KG1a细胞在体外可诱导T细胞呈克隆性增殖，此优势增殖的克隆性T细胞具有特异性细胞毒作用，对KG1a细胞具有选择性杀伤作用。