采用荧光定量PCR溶解曲线法监测人TCR alpha链CDR3谱系漂移技术的初步探讨

目的:初步探讨荧光定量PCR溶解曲线分析技术监测人外周血T细胞TCR alpha链CDR3谱系漂移(单/寡/多克隆增生).方法:提取4例正常人、2例淋巴瘤型白血病患者PBMC中的总RNA,逆转录成cDNA,以32个人TCR alpha 链胚系可变区基因家族 (TRAV)设计上游引物,共同的TCR alpha 胚系链恒定区基因家族(TRAC)设计下游引物,荧光定量PCR(FQ-PCR)扩增32个TRAV基因各家族CDR3谱系,溶解曲线法分析各家族CDR3谱系的单/寡/多克隆增生.结果:正常人外周血T细胞TCR alpha链32个家族CDR3表达频率不一致,各家族PCR产物的溶解曲线谱型图(melting curve spectratyping)呈现熔点不同的CDR3多态性,为多克隆增生的高斯分布,2例淋巴瘤型白血病患者外周血T细胞TCR alpha链32个家族CDR3表达频率不一致,部分家族呈缺失状态,患者各家族PCR产物的溶解曲线谱型图上,多数家族为多克隆增生的高斯分布,但每个患者均出现数量不等的单克隆和寡克隆增生家族.结论:荧光定量PCR溶解曲线分析TCR alpha链CDR3谱系漂移技术方法稳定简便,能较好地监测正常人和临床样本外周血T细胞TCR alpha链CDR3谱系漂移(单/寡/多克隆增生).     

活动性肺结核患者α/β TCR基因重排及CDR3谱型分析

目的:建立多重PCR方法扩增α/β TCR全长序列,分析活动性肺结核患者病变局部T淋巴细胞α/β TCR基因重排特点及CDR3谱型.方法:分离结核患者肺泡灌洗液中的淋巴细胞,提取RNA后用SMART方法逆转录,运用根据现有文献设计的α和β TCR扩增引物,进行多重PCR扩增以获得其全长序列,构建重组质粒并测序,利用DNAstar及网上TCR资源分析序列.结果:3例患者共获得24个α链序列,13个β链序列.α链以AV1S2(54%)、AV12S3(41%)、AV12S2(5%)为主;β链以BV2(38%)、BV29S1(46%)、BV14(3%)、BV4S2(3%)为主.同一病例及不同病例之间CDR3区呈现多样性,但是标本1、标本3各有一条β链的CDR3氨基酸序列相同:SVGTGTLHQETQY;标本2和标本3的各有2条α链CDR3序列相同:AVRDWAGNMLT;标本2的一个α链和标本3的一个α链的CDR3均有:AV…DNN…RLM序列.结论:建立了TCRα和β链全长序列的多重PCR扩增方法.结核患者病变局部克隆性增殖的TCR α和β链谱型呈限制性取用,克隆增生的T淋巴细胞来自不同的亚群,但是相同的CDR3序列对于识别MTB多肽可能具有特异性.     

“荧光定量PCR溶解曲线法”监测人TCRβ链CDR3谱系漂移技术的建立

目的 建立"荧光定量PCR溶解曲线分析技术"监测人外周血T细胞TCR β链CDR3谱系漂移(单/寡/多克隆增生).方法 提取4例正常人、9例大肠癌患者外周血单个核细胞(peripheral blood mononuclear cell-PBMC)中的总RNA,逆转录成cDNA,以26个人TRBV基因家族设计上游引物,共同的TRBC基因设计下游引物,荧光定量PCR(FQ-PCR)扩增26个TRBV基因各家族CDR3谱系,溶解曲线法分析各家族CDR3谱系的单/寡/多克隆增生.结果 正常人外周血T细胞TCR β链26个家族CDR3表达频率不一致,各家族PCR产物的"溶解曲线谱型图"(melting curve spectratyping)呈现溶点不同的CDR3多态性,为多克隆增生的高斯分布;9例大肠癌患者的外周血TCR β链CDR3谱系的26个家族CDR3表达频率不一致,有的患者部分家族呈缺失状态,患者各家族PCR产物的"溶解曲线谱型图"上,多数家族为多克隆增生的高斯分布,但每个患者均出现数量不等的单克隆和寡克隆增生家族.结论 "荧光定量PCR溶解曲线分析TCR CDR3谱系漂移技术",方法稳定简便,能较好的监测正常人和临床样本外周血T细胞TCR β链CDR3谱系漂移(单/寡/多克隆增生).     

TCR BV CDR3谱型与自身免疫性疾病

自身抗原特异性T细胞克隆性增生在自身免疫病的发生发展中起重要作用，TCR CDR3区是T细胞直接与抗原接触的位点，一种CDR3序列代表一个T细胞克隆，通过对TCR BV CDR3谱型分析及序列测定可迅速发现自身免疫性T细胞克隆，指导疾病的免疫治疗。     

077 TCR BV CDR3谱型与自身免疫性疾病

自身抗原特异性T细胞克隆性增生在自身免疫病的发生发展中起重要作用，TCR CDR3区是T细胞直接与抗原接触的位点，一种CDR3序列代表一个T细胞克隆，通过对，TCR BV CDR3谱型分析及序列测定可迅速发现自身免疫性T细胞克隆，指导疾病的免疫治疗。     

抗病毒治疗对CHB患者外周血TCRβ链CDR3谱系的影响

目的:分析慢性乙型肝炎(CHB)患者抗病毒治疗前后T淋巴细胞受体(TCR)β链各家族互补决定区3(CDR3)谱系的变化,了解抗病毒治疗前后T细胞应答的变化。方法:采用荧光定量PCR(FQ-PCR)溶解曲线法对11例CHB患者抗病毒治疗前后外周血单个核细胞(PBMC)T淋巴细胞受体β链可变区(TCR BV)基因各家族CDR3谱系进行分析,了解抗病毒治疗前后T细胞应答的变化。分析TCR CDR3谱系与CHB患者血清病毒载量的关系。结果:11例CHB患者抗病毒治疗后多个TCR CDR3谱系均出现了不同程度偏移。低病毒载量组(HBV DNA≤104拷贝/ml)治疗后谱型偏移率显著高于高病毒载量组(HBV DNA≥105拷贝/ml)。结论:CHB患者抗病毒治疗后单寡谱型偏移率与治疗前血清HBV DNA的水平相关。     

强直性脊柱炎患者外周血TCR Vα CDR3谱系基因扫描分析研究

目的:探讨强直性脊柱炎(AS)患者外周血T细胞受体α链可变区互补决定区3(TCR Vα CDR3)谱系多态性,为AS的免疫发病机制的研究提供实验基础。方法:采用反转录-聚合酶链反应(RT-PCR)扩增34个TCR Vα亚家族,经免疫扫描谱型技术分析AS患者外周血单个核细胞(PBMC)中T细胞TCR Vα CDR3的谱系漂移情况。结果:5例正常健康对照PB-MC TCR Vα CDR3谱型多数呈高斯分布。所有AS患者外周血T细胞均出现多个TCR Vα亚家族谱型的异常改变,异常峰型包括:单峰、寡峰/寡峰趋势、偏峰和不规则异常峰型。34个TCR Vα亚家族中,共有17个亚家族在少数患者中的扫描谱型呈单峰即单克隆增生。结论:AS患者PBMC TCR Vα CDR3谱系具有显著多态性,表明T细胞在AS免疫发病机理中扮演重要角色。单/寡克隆增生的T细胞有可能是AS发病中的自身反应性T细胞,将为AS的发病机制的进一步研究提供基础依据。     

脐血中TCRVβ亚家族T细胞的分布和克隆性分析

目的:了解正常脐血中TCR Vβ亚家族T细胞的分布和克隆性。方法:利用RT-PCR分别扩增13例正常脐血单个核细胞的TCR Vβ 24个亚家族基因的CDR3,了解各Vβ亚家族的表达情况。阳性的PCR产物进一步经荧光素标记和基因扫描分析产物的CDR3长度,了解T细胞克隆性。10例正常人外周血和T细胞株Molt-4及Jurkat作为对照。 结果:正常脐血T细胞仅选择性表达24个Vβ亚家族的38.78%±16.26%,以Vβ3、5、8、9和13为多见,而正常人外周血T细胞则表达全部24个Vβ亚家族。基因扫描显示正常脐血和正常人外周血的全部PCR产物均呈多峰图象。结论:正常脐血存在不完全TCR Vβ亚家族T细胞,所有TCR Vβ亚家族T细胞均呈多克隆性。     

葡萄膜炎患者外周血TCR Vα谱系多态性分析

目的 探讨葡萄膜炎患者外周血T细胞受体α链可变区互补决定区3 (TCR Vα CDR3)谱系特点及多态性.方法 采用RT-PCR扩增葡萄膜炎患者外周血单个核细胞(PBMC)中TCR Vα 34个亚家族,经免疫扫描谱型技术分析34个亚家族谱型.结果 5例正常健康人PBMC TCR Vα CDR3谱型多数呈高斯分布,4例葡萄膜炎患者外周血T细胞均出现多个TCR Vα亚家族谱型的异常改变,异常峰型包括单峰、寡峰/寡峰趋势,偏峰和不规则异常蜂型.34个TCR Vα亚家族中,不同亚家族异常峰型出现的频率不同,非正态异常峰型出现频率较高的亚家族有Vα13和Vα17(均为3/4),而Vα1.1、Vα10、Vα20、Vα28和Vα28亚家族均未出现异常峰型.TCR Vα7在HLA-B27阴性的患者(U2)中出现异常峰型,在HLA-B27阳性的3个患者(U1、U3、U4)中并未出现这个亚家族的异常;TCR Vα13则相反,即在HLA-B27阳性的3个患者中均出现异常峰型,而在HLA-B27阴性的患者中正常.结论 葡萄膜炎患者PBMC TCR Vα CDR3谱系具有显著多态性特点,单/寡克隆增生的T细胞有可能是葡萄膜炎发病中的自身反应性T细胞.     

不同HBV感染状态患者外周血CD4~+CD25~+Tregs TCR CDR3谱系漂移特征分析

目的探讨慢性HBV携带者、慢性乙型肝炎(chronic hepatitis B,CHB)及急性乙型肝炎(acute hepatitis B,AHB)这3种不同HBV感染状态下患者外周血中CD4~+ CD25~+调节性T细胞(T regulatory cells,Tregs)T细胞受体(T cell receptor,TCR)β链各家族互补决定区3(complementarity-determining region 3,CDR3)谱系漂移特征。方法采集3例正常人、5例慢性HBV携带者、12例CHB及5例AHB患者外周抗凝静脉血,分离外周血单个核细胞(peripheral blood mononuclear cell,PBMC);磁珠分选法分选CD4~+ CD25~+Tregs,提取总RNA,逆转录合成c DNA;根据TCRβ链24个可变区基因(TRBV)家族设计相应的上游引物,并在β链恒定区(BC)设计1条共用的FAM荧光标记下游引物及对照引物。PCR扩增出24个包含完整CDR3区的TRBV家族的PCR产物,电泳鉴定目的片段;PCR产物送上海基康用毛细管电泳法进行基因扫描;用Peak Scanner Software v1.0软件分析TRBV家族CDR3谱系特征。结果不同HBV感染状态下24个TRBV家族CDR3谱系图均呈现一个或者多个形态不一、数量不等的单峰、寡峰、偏峰谱型,其中一些家族表达极低或缺失,在1.5%琼脂糖凝胶电泳图上多数家族于预测范围大小处呈现1条模糊条带,部分家族出现清晰条带或无条带;对不同HBV感染者间各TRBV家族CDR3谱系偏移率进行比较发现:慢性HBV携带者中BV7谱系偏移率明显高于CHB及AHB患者(P均0.05),CHB患者中BV15谱系偏移率明显高于慢性HBV携带者及AHB患者(P均0.05),AHB患者中BV23谱系偏移率明显高于CHB及慢性HBV携带者(P均0.05)。CHB患者外周血CD4~+ CD25~+Tregs TRBV家族CDR3克隆增生总体异常率与HBV DNA载量呈正相关关系(r=0.576 5,P=0.049 8)。结论部分优势利用的TRBV家族可能在感染HBV后免疫耐受以及清除病毒中发挥重要作用。     

识别猪SLA的特异性人T细胞系TCR BV基因取用格局和CDR3结构多样性分析

不同T细胞克隆TCR分子的序列不同 ,所识别的抗原特异性也不同。其中第三互补决定区 (CDR3)变异最大 ,是TCR主要的抗原结合部位。本文采用荧光标记半定量PCR技术 ,用DNA测序仪作程序分析 ,了解猪细胞抗原致敏前后的人T细胞群和 5个T细胞系 2 4个TCRBV基因家族取用格局 ,并以TCRα链C区的基因片断作为内参对取用情况作定量估计。发现首次抗原致敏后培养 2周的T细胞除了BV2 4、BV8和BV10未能检测出 ,其它BV基因都有不同程度的取用。然而 ,5个细胞系的TCRBV基因呈现十分有限的取用格局 ,其中两个CD4+ T细胞系都取用BV12和BV14;3个CD8+ T细胞系中都优势取用BV1,有两个还取用BV19。CD4+ T细胞系和CD8+ T细胞系之间TCRBV无交叉取用 ,提示两类细胞识别的抗原表位存在差异。进一步用变性凝胶扫描分析上述T细胞系取用TCRBV中的CDR3的多样性 ,发现未经抗原致敏的T细胞BV的CDR3结构为多峰型且呈正态分布 ,表明涉及多种结构不同的细胞克隆 ;而抗原特异性T细胞系CDR3除了一个CD8+ T细胞系BV1有两个主峰外其它无例外地都显示单峰或者仅一个主峰 ,这从另一个角度证明建系T细胞的单克隆性。     

Identification of oligoclonal CD4 T cells in diffuse large B cell lymphomas

Human B cell lymphomas often contain CD4 T cells. Here we show that, in diffuse large B cell lymphomas (DLCL), such T cells are oligoclonal. The CDR3 lengths and nucleotide sequences of oligoclonal TCRBV of CD4 T cells in an original and relapsed lymphoma from one patient were compared. Three BV23 sequences were identical (12/17 and 16/16 clones in primary and relapsed lymphomas, respectively), but were absent in CD4 T cells from another patient's DLCL. Two of the repetitive BV23 sequences were found in peripheral blood CD4 T cells (5/17 clones); gamma-irradiated DLCL from this patient stimulated syngeneic BV23 response in CD4 cells (92% of BV23 had the same CDR3 length). Skew in TCRBV representation was observed in CD4 T cells from all the DLCL. One DLCL, with overrepresentation of BV13S1 in CD4 cells, stimulated the same TCR in CD4 cells from three unrelated individuals. These findings support the conclusion that there is clonal selection of CD4 T cells in DLCL.     

Regulatory T cells play a role in T-cell receptor CDR2 peptide regulation of experimental autoimmune encephalomyelitis

Eliciting T-cell receptor (TCR) -specific responsiveness has been known to provide an effective autoregulatory mechanism for limiting inflammation mediated by T effector cells. Our previous use of TCR peptides derived from the CDR3 regions of a pathogenic TCR effectively reversed ongoing experimental autoimmune encephalomyelitis (EAE) in a humanized TCR transgenic model. In this study, we use the TCR BV8S2 CDR2 peptide in the non-transgenic C57BL/6 EAE model to down-regulate the heterogeneous TCR BV8S2(+) MOG-35-55-specific pathogenic T-cell population and demonstrate successful treatment of EAE after disease onset. Suppression of disease was associated with reduced MOG-35-55-specific and non-specific T-cell production of interleukin-17a and interferon-γ in the central nervous system, as well as reduced numbers of CD4(+) and Foxp3(+) T cells in the central nervous system. With the use of Foxp3-GFP and Foxp3 conditional knockout mice, we demonstrate that the TCR CDR2 peptide treatment effect is dependent on the presence of Foxp3(+) regulatory T cells and that regulatory T cell numbers are significantly expanded in the periphery of treated mice. Hence, TCR CDR2 peptide therapy is effective in regulating heterogeneous, pathogenic T-cell populations through the activity of the Foxp3(+) regulatory T cell population.     

Single cell analysis of T cells infiltrating labial salivary glands from patients with Sj?gren's syndrome.

Sj?gren's syndrome (SS) is an autoimmune disease characterized by lymphocytic infiltration into the lacrimal and salivary glands leading to symptomatic dry eyes and mouth. To analyze the function of T cells infiltrating the labial salivary glands, we analyzed T cell receptor (TCR) beta and alpha chains, the expression of various cytokine mRNAs, and apoptosis associated genes in predominant TCR BV2+ T cells in the labial salivary glands of patients with SS at the single cell level. TCR BV2+ T cells in the labial salivary glands were sorted as single cells by flow-cytometry, and then examined by a single cell polymerase chain reaction (PCR). We isolated 18 TCR BV2+ T cell clones from three patients with SS. In six clones, there were highly conserved amino acid motifs (RDxG, GNT, QGxxQETQ) in the CDR3 region of the TCR beta chain. Three of the six clones showed conserved amino acids (EDxTG, or ExxTG) in the CDR3 region of the TCR alpha chain, suggesting restricted T cell epitopes. All TCR BV2+ clones expressed IL-2 mRNA, and six clones were able to produce IL-4, indicating that the cells were Th0 type T cells. All TCR BV2+ clones in the labial salivary glands were CD4+ T cells, and ten clones overexpressed Fas antigen at the mRNA level. In contrast, only one clone expressed Fas-ligand (Fas-L) mRNA, and neither perforin nor granzyme A/B was expressed. In conclusion, these findings support the notion that TCR BV2+ T cells that infiltrate labial salivary glands recognize restricted epitopes and function as CD4+ Th0 type T cells in the induction phase of autoimmunity.     

Analysis of the interindividual conservation of T cell receptor alpha- and beta-chain variable regions gene in the peripheral blood of patients with systemic lupus erythematosus

The aim of this study was to find conserved motifs in specific T cell receptor (TCR) alpha- and beta-chains, and to analyse the association between complementarity determining region 3 (CDR3) spectratype and systemic lupus erythematosus (SLE) activity. TCR alpha-and beta-chain CDR3 spectratypes were analysed in 20 SLE patients. The CDR3 spectratypes of three patients were monitored over time, and the CDR3 regions of clonally expanded T cells were sequenced. CDR3 spectratype analysis showed prominent usage of TCR AV8, AV14, AV23, AV30, AV31, BV2, BV8, BV11, BV14, BV16, BV19 and BV24 families in SLE patients. The CDR3 spectratype showed dynamic change correlating with SLE activity. The sequence of the CDR3 region in clonally expanded T cells suggested a conserved GGX amino acid motif in both alpha- and beta-chains. The Ja34 and Jb2s1 region genes were found in high frequency. Both TCR Valpha and Vbeta gene usage is highly restricted in SLE, suggesting that the TCRs recognize a limited number of antigenic epitopes. The conserved motifs and limited use of joining region genes may indicate the recognition of similar antigenic epitopes in multiple individuals.     

Dominance of the BV17 element in nickel-specific human T cell receptors relates to severity of contact sensitivity

Hypersensitivity to nickel (Ni) represents the most common manifestation of contact allergy in humans. The role of metal-specific T cells in this disease is well established, but the molecular interactions involved in their activation are poorly understood. We examined the T cell receptor (TCR) repertoire in T cells activated with either NiSO₄ or NiSO₄-treated human serum albumin from six allergic patients. For the three most hyperreactive donors, we found a strong over-represention of the TCR BV17 element. TCR sequencing for one of these donors revealed an additional skewing for AV1 as well as a selection for an N region encoded argine at position 95 of the BV17 complementarity determining region (CDR)3. Since Arg is not known to participate in Ni complexing, we suppose that this selection is driven by contacts with peptide rather than nickel. However, the CDR1 of BV17 contains a unique combination of amino acids (HDA) that bears similarities to known motifs in Ni-binding proteins or peptides. We therefore propose that the severe hypersensitivity reactions found in BV17 over-expressors may be the result of Ni²⁺ ions bridging the germ-line-encoded BV17 CDR1 loop to corresponding sites in the major histocompatibility complex/peptide complex and thereby creating a superantigen-like enhancement of weak TCR-peptide contacts.     

Analysis of the Conservation of T Cell Receptor Alpha and Beta Chain Variable Regions Gene in pp65 Peptide-Specific HLA-A＊0201-Restricted CD8^＋ T Cells

Many viral epitope specific T cell receptors （TCRs） in MHC-matched individuals have been demonstrated to involve conserved amino acid motifs in β chain complementarity-determining region 3 （CDR3）. However, it is not sure whether the conserved motifs can also be found in TCR β chain. In previous studies, we developed a modified method to enlarge the percentage of cytomegalovirus （CMV） pp65 peptide-specific CD8^＋ T cells in PBMC by continuous peptide stimulation in vitro, which provides sufficient number of specific T cells for detection. In this study, we further analyzed the restrictive usage of TCR Vα and Vβ gene families and investigated the CDR3 gene sequence of pp65 peptide-specific CD8β T cells. Analysis of CDR3 spectratypes suggested a restricted usage of TCR α chain AV8, AV12, AV21, AV31 families and TCR βchain BV3, BV14, BV21, BV23, BVll families in donor CD8^＋ T cells stimulated by pp65 peptide. The sequences of these T cells involved similar sequence （TX） G （X） A in CDR3 region of TCR α chain and L （XT） G （X） A in TCR β chain.