CD4+CD25+调节性T细胞防治移植物抗宿主病的研究进展

异基因造血干细胞移植是目前治疗白血病、淋巴瘤等恶性血液疾病的有效手段,但是其疗效却受到了移植后发生的移植物抗宿主病的制约与限制.近年来,随着对CD4+CD25+调节性T细胞(Treg)研究的深入,人们发现这一T细胞亚群不仅在维持免疫自稳和抑制异体免疫应答方面具有重要作用,并且对于预防与治疗移植物抗宿主病也有一定的潜力.     

供者基因表达谱帮助预测受者移植物抗宿主病

加拿大蒙特利尔大学的CLaude Perreault博士及其同事在1月的《公共科学图书馆·医学》（PLos Med，2007；4：e23．）杂志上报告，在同种异体造血细胞移植（AHCT）中，供者CD4^＋和CD8^＋T细胞差别基因表达可预测受者移植物抗宿主病（GVHD）。     

异基因骨髓移植中T细胞表达Ly49A与移植物抗宿主病发生相关

杀伤细胞抑制性受体 (ＫｉｌｌｅｒＩｎｈｉｂｉｔｏｒｙＲｅｃｅｐｔｏｒ,ＫＩＲ)是一种主要表达在ＮＫ、Ｔ细胞上的抑制性信号传递分子[1] 。鼠的ＫＩＲ分子被称为Ｌｙ4 9家族(Ｌｙ4 9Ａ Ｉ)。在细胞免疫识别阶段 ,Ｌｙ4 9分子特异地与不同的ＭＨＣＩ分子配体结合 ,传递抑制性信号 ,抑制杀伤细胞的早期活化。移植物抗宿主病(ＧＶＨＤ)主要是供者Ｔ细胞活化后对宿主细胞和组织的攻击所致。Ｌｙ4 9Ａ ＭＨＣＩ作为Ｔ细胞活化的抑制性信号传递分子 ,其在ＧＶＨＤ发生中的表达如何将有助于揭示ＫＩＲ分子参与控制ＧＶＨＤ的可能机制。本文采用…     

趋化因子受体CCR5在急性移植物抗宿主病防治中的研究

趋化因子受体CCR5(CC chemokine receptor 5)属于β趋化因子受体,表达于人体多种免疫细胞表面,与配体特异性结合发挥募集趋化免疫细胞定向迁移的作用,在急性移植物抗宿主病(acute graft versus host disease,aGVHD)的发生过程中发挥关键作用,逐渐成为移植免疫研究的热点...     

CD4+CD25+调节性Treg细胞与急性移植物抗宿主病

CD4+CD25+Treg细胞是调节性T细胞的一个重要亚群,具有免疫无能和免疫抑制的特性,在防止自身免疫病发生、诱导移植耐受及调节肿瘤免疫方面起着重要作用。急性移植物抗宿主病(aGVHD)是异基因造血干细胞移植后最严重的并发症。近年来,有关CD4+CD25+Treg细胞与aGVHD关联性的研究取得了很大的进展,特别是该类细胞可有效地降低aGVHD的发生及作为aGVHD风险预测的一项重要指标。本文就CD4+CD25+Treg细胞的特性、免疫调节作用机制及CD4+CD25+Treg细胞与aGVHD的关联性的一些研究进展作一综述。     

系统性红斑狼疮患者外周血CD4+和CD8+T细胞PD-1的表达和意义

目的 探讨程序性死亡分子1 (PD-1)在系统性红斑狼疮(SLE)患者外周血CD4+和CD8+T细胞上的表达及临床意义.方法 应用流式细胞仪检测51例SLE患者和38例健康对照者外周血T细胞亚群表面PD-1表达水平,比较SLE稳定组、活动组和健康对照组以及狼疮肾炎组和无狼疮肾炎组之间CD4+和CD8+T细胞表面PD-1表达的百分比,并分析其与临床表现及实验室检查数据的相关性.结果 SLE活动组CD4+T细胞PD-1表达水平高于健康对照组和不活动组,差异均有统计学意义(P＜0.05).SLE活动组、稳定组CD8+T细胞PD-1表达水平均高于健康对照组,差异有统计学意义(P＜0.05).狼疮肾炎患者CD4+PD-1+和CD8+PD-1+T细胞分别高于无狼疮肾炎患者(P＜0.01).SLE患者中抗dsDNA抗体、抗Sm抗体、抗核小体抗体阳性组外周血CD4+和CD8+T细胞PD-1表达水平均高于对应阴性组.SLE患者CD4+和CD8+T细胞PD-1表达百分率与SLE疾病活动度指数(SLEDAI)、尿蛋白定量呈正相关,与补体C3呈负相关.结论 SLE患者外周血CD4+和CD8+T细胞PD-1表达异常,与SLEDA1和自身抗体产生有明确的相关性.     

CD8+T调节细胞的研究进展

调节性T细胞(Regulation T cell, Treg)是参与外周耐受性调节的一个重要细胞群。目前发现具有耐受调节作用的T细胞包括了CD4+ Treg细胞、 Th3细胞、 Treg1细胞、 NKT(nature killer cells)细胞、 Th17细胞和CD8+Treg细胞等[1]。     

CD8+T细胞的调节性特性

随着免疫学,内科学及移植学的发展,CD8+T细胞日益受到重视.它不仅是细胞毒性效应T细胞,而且也是具有免疫抑制作用的调节性T细胞.CD8+调节性T细胞在生理条件下对机体自身稳态的维持,以及在器官移植,自身免疫性疾病及病毒感染和肿瘤等病理状态下都起着较为重要的作用.     

急性乙型肝炎患者HBV特异性CD8~+ T细胞受体α和β链亚家族特点

目的:分析急性乙型肝炎患者HBV特异性CD8+ T细胞受体α和β链亚家族特点。方法:从1例HLA*0201的急性乙型肝炎患者的外周血分离外周血单个核细胞(PBMC),用乙肝抗原HBsAg表位S335-343多肽和细胞因子刺激PBMC以诱导CD8+ T增殖,用流式细胞仪分选出特异性CTL到96孔培养板,培养10～14 d后,提取细胞RNA,PolyA介导反转录,巢式PCR扩增TCR Vα和TCR Vβ,并用非特异性CD8+ T细胞作为对照。对扩增产物分别进行直接测序和克隆测序分析。结果:从HBV急性肝炎患者分离的HBsAg335-343表位特异性CD8+ T细胞扩增出15个Vα亚家族和10个Vβ亚家族,其中用少量CTL仅检出Vα2、Vα9和TCR Vβ3、Vβ4、Vβ9,提示这几种亚家族可能为该特异性CTL TCR的优势取用亚家族,除Vα2呈现3种序列和Vβ9呈现2种序列外,其他亚家族内序列单一;而从患者非特异性CD8+ T对照细胞中可扩增到所有的32个TCRVα和25个Vβ亚家族,且同一亚家族序列呈现高度多样性。结论:急性乙型肝炎患者HBV特异性CD8+ T细胞受体存在优势利用的特点,可能是由于针对同一抗原的特异性CD8+ T细胞克隆性增殖所致,其机制有待进一步分析。     

脐血和新生儿外周血CD4+CD25+调节性T细胞的表型特征及意义

目的 探讨脐血和新生儿外周血中CD4 CD25 调节性T细胞的表型特征及其意义.方法以18份脐血和9份新生儿外周血为标本,细胞膜表面抗原采用单抗直接标记法,检测胞内抗原(CD152、FoxP3)时先标记膜表面抗原,固定破膜后再标记胞内抗原,应用多参数流式细胞仪进行检测和结果分析.结果脐血和新生儿外周血中的CD4 CD25 T细胞显示为独立的细胞群,脐血中该群细胞占CD4 T细胞比例为(9.26±2.43)%,新生儿外周血中的比例则为(9.35±2.30)%;在表型方面,大部分是CD45RA 的细胞,同时表达CD62L、胞浆内的CD152,也表达FoxP3,CD4 CD25 FoxP3 占CD4 T细胞比例为(1.92±0.28)%.结论 脐血和新生儿外周血中存在着一群单纯且水平较高的CD4 CD25 调节性T细胞,它们可能在发挥对母体非遗传性抗原的耐受及防止母体对胎儿的排斥反应中具有独特的作用.     

Chemokines,chemokine receptors and CD4+CD25+ regulatory T cells

The fields of regulatory T (Treg) cells and chemokines/chemokine receptors have progressed rapidly in the last few years. Treg cells, especially CD4⁺CD25⁺ Treg cells, play a critical role in maintaining self-tolerance and immune homeostasis. Chemokines and chemokine receptors are crucial for lymphoid development, homing and immunological regulation. This review will discuss the biological effects of chemokines and chemokine receptors on regulating the migration and development of CD4⁺CD25⁺ Treg cells, and the potential clinical implications of these findings when considering chemokine receptors as therapeutic targets.     

CD8 chemokine receptors in chronic obstructive pulmonary disease

Increased lung CD8 cells and their expression of chemokine receptors CXCR3 and CCR5 have been previously reported in chronic obstructive pulmonary disease (COPD). Alterations of CD8-CCR3 and -CCR4 expression and their ligands in COPD patients have not been fully investigated. The objective of this study was to assess in COPD patients: (i) broncho-alveolar lavage (BAL) CD8 CCR3 and CCR4 expression in COPD patients; and (ii) airway levels of the CCR3 ligands, CCL11 and CCL5. Multi-parameter flow cytometric analysis was used to assess BAL CD3 and CD8-chemokine receptor expression in COPD patients, smokers and healthy non-smokers (HNS). CCL5 and CCL11 levels were measured in BAL, and from the supernatants of lung resection explant cultures. CD8-CCR3 and -CCR5 expression (means) were increased in COPD patients (22% and 46% respectively) and smokers (20% and 45%) compared with HNS (3% and 22%); P < 0.05 for all comparisons. CD3CXCR3 expression was raised in smokers and COPD while CD8CXCR3 and CD3 and CD8 CCR4 expression was similar between groups. CD8CCR5 expression correlated to smoking pack years (r = 0.42, P = 0.01). COPD explants released more CCL5 compared with smokers (P = 0.02), while there was low level CCL11 production. CD8CCR3 and CCR5 expression appear to be regulated by cigarette smoke exposure. We show that COPD lung tissue released more CCL5, suggesting a role for CCL5-CCR3 signalling in pulmonary CD8 recruitment in COPD.     

CD4+CD25+免疫调节性T细胞对CD4+T细胞介导的移植物抗宿主病预防作用的研究

目的研究CD4+CD25+免疫调节性T(Treg)细胞在小鼠骨髓移植后,对移植物抗宿主病的预防作用及其作用机制.方法用C3H(H-2k)小鼠骨髓作为供体,提取C3H(H-2k)小鼠CD4+T及CD4+CD25+T细胞,C3H×B6(H-2k/b)F1小鼠为骨髓移植的受者.在受者接受致死量全身放射后,输注供者去除T细胞的骨髓(ATBM),使其造血功能重建(ATBM组).于不同的实验组给予CD4+(CD4组)T细胞,CD4+CD25+T(CD25组)或二者同时输注(CD4/CD25组).观察各组小鼠移植物抗宿主病(GVHD)的发生率.结果所有10只ATBM组小鼠至骨髓移植后60天仍全部存活,无GVHD发生;所有10只CD4组小鼠在骨髓移植10天内全部死于GVHD(P＜0.01);所有5只CD25组小鼠于骨髓移植后60天仍全部存活,无明显GVHD发生(P＞0.05);同样,所有6只CD4/CD25组小鼠至骨髓移植后仍全部存活,无明显GVHD发生(P＞0.05).结论在同种异基因小鼠的骨髓移植模型中,CD4+CD25+T不诱导GVHD的发生,并有预防CD4+T细胞介导的GVHD发生的作用.     

免疫磁珠负性分离纯化小鼠脾脏CD8+ T细胞

目的 探讨小鼠脾脏CD8 T细胞的免疫磁珠负性分选方法,并对分选后所得细胞进行纯度、活力及功能检测.方法 以免疫磁珠负性分选法从小鼠脾脏细胞中分离CD8 T细胞,流式细胞术检测所得细胞的纯度,台盼蓝检测细胞活力并用ConA刺激检测增殖能力. 结果 经过流式细胞仪测定免疫磁珠负性分选后的小鼠脾脏CD8 T细胞纯度达到(91.6±3.6)%,台盼兰染色细胞活力为(94.9±3.2)%,ConA刺激72 h后有(56.3±1.7)%的细胞增殖.结论 免疫磁珠负性分选法能够分选出高纯度的CD8 T细胞,并且不影响分选靶细胞的细胞活力和功能.     

Antibody-mediated delivery of antigen to chemokine receptors on antigen-presenting cells results in enhanced CD4+ T cell responses

Here, we have investigated if targeting of T cell epitopes to chemokine receptors results in improved CD4+ T cell responses. Mouse monoclonal antibodies (mAb) with kappaL chains were targeted to various chemokine receptors expressed on human monocytes or immature dendritic cells (DC), and proliferation of cloned human, DR4-restricted CD4+ T cells specific for mouse Ckappa(40-48) was measured. When using monocytes as antigen-presenting cells, mAb specific for CCR1, CCR2, CCR5, and CXCR4 were 100-10,000-fold more efficient at inducing T cell proliferation when compared to isotype-matched control mAb on a per molecule basis. Targeting of immature DC was less effective and was only seen with anti-CCR1 and anti-CXCR4 mAb. Anti-chemokine receptors mAb required to be processed by the conventional endosomal MHC class II presentation pathway. The mAb did not induce signaling through the chemokine receptors as they failed to induce mobilization of cytosolic Ca2+ and actin polymerization. They also failed to induce APC maturation. The results strongly suggest that chemokine receptors channel antigen into the endocytic pathway for presentation on MHC class II molecules. Targeting T cell epitopes to chemokine receptors by recombinant antibody should be a useful vaccine strategy for the induction of strong CD4+ T cell responses.     

CD8+ CD28- and CD8+ CD57+ T cells and their role in health and disease

Chronic antigenic stimulation leads to gradual accumulation of late-differentiated, antigen-specific, oligoclonal T cells, particularly within the CD8(+) T-cell compartment. They are characterized by critically shortened telomeres, loss of CD28 and/or gain of CD57 expression and are defined as either CD8(+) CD28(-) or CD8(+) CD57(+) T lymphocytes. There is growing evidence that the CD8(+) CD28(-) (CD8(+) CD57(+)) T-cell population plays a significant role in various diseases or conditions, associated with chronic immune activation such as cancer, chronic intracellular infections, chronic alcoholism, some chronic pulmonary diseases, autoimmune diseases, allogeneic transplantation, as well as has a great influence on age-related changes in the immune system status. CD8(+) CD28(-) (CD8(+) CD57(+)) T-cell population is heterogeneous and composed of various functionally competing (cytotoxic and immunosuppressive) subsets thus the overall effect of CD8(+) CD28(-) (CD8(+) CD57(+)) T-cell-mediated immunity depends on the predominance of a particular subset. Many articles claim that CD8(+) CD28(-) (CD8(+) CD57(+)) T cells have lost their proliferative capacity during process of replicative senescence triggered by repeated antigenic stimulation. However recent data indicate that CD8(+) CD28(-) (CD8(+) CD57(+)) T cells can transiently up-regulate telomerase activity and proliferate under certain stimulation conditions. Similarly, conflicting data is provided regarding CD8(+) CD28(-) (CD8(+) CD57(+)) T-cell sensitivity to apoptosis, finally leading to the conclusion that this T-cell population is also heterogeneous in terms of its apoptotic potential. This review provides a comprehensive approach to the CD8(+) CD28(-) (CD8(+) CD57(+)) T-cell population: we describe in detail its origins, molecular and functional characteristics, subsets, role in various diseases or conditions, associated with persistent antigenic stimulation.     

Circulating CD4+CD8+ T lymphocytes in patients with Kawasaki disease

We serially monitored cell surface antigen expression on mononuclear cells in peripheral blood isolated from patients with Kawasaki disease (KD), and found, for the first time, that a markedly increased number of CD4⁺CD8⁺ T lymphocytes was present in some of the patients (11 of the 24 cases). The cases of five of these 11 patients were complicated with coronary artery lesion (CAL); the 13 patients with normal numbers of CD4⁺CD8⁺ T lymphocytes did not have CAL. The patients' age, sex and grade of systemic inflammation evaluated by peripheral leucocyte count and serum C-reactive protein levels were not correlated to the number of CD4⁺CD8⁺ T lymphocytes. Other cell surface antigen characteristics of the CD4⁺CD8⁺ T lymphocytes included CD3⁺, CD45RA⁺, CD45RO⁺, CD16^?, and HLA-DR⁺. These results indicate that the surface antigen characteristics of the KD peripheral blood examined were the same as those of Epstein–Barr virus infection without CD45RA⁺. These findings provide useful information for the analysis of the pathogenesis of KD.     

Polyfunctional response by ImmTAC (IMCgp100) redirected CD8+ and CD4+ T cells

The success of immune system‐based cancer therapies depends on a broad immune response engaging a range of effector cells and mechanisms. Immune mobilizing monoclonal T cell receptors (TCRs) against cancer (ImmTAC™ molecules: fusion proteins consisting of a soluble, affinity enhanced TCR and an anti‐CD3 scFv antibody) were previously shown to redirect CD8⁺ and CD4⁺ T cells against tumours. Here we present evidence that IMCgp100 (ImmTAC recognizing a peptide derived from the melanoma‐specific protein, gp100, presented by HLA‐A*0201) efficiently redirects and activates effector and memory cells from both CD8⁺ and CD4⁺ repertoires. Using isolated subpopulations of T cells, we find that both terminally differentiated and effector memory CD8⁺ T cells redirected by IMCgp100 are potent killers of melanoma cells. Furthermore, CD4⁺ effector memory T cells elicit potent cytotoxic activity leading to melanoma cell killing upon redirection by IMCgp100. The majority of T cell subsets belonging to both the CD8⁺ and CD4⁺ repertoires secrete key pro‐inflammatory cytokines (tumour necrosis factor‐α, interferon‐γ, interleukin‐6) and chemokines (macrophage inflammatory protein‐1α‐β, interferon‐γ‐inducible protein‐10, monocyte chemoattractant protein‐1). At an individual cell level, IMCgp100‐redirected T cells display a polyfunctional phenotype, which is a hallmark of a potent anti‐cancer response. This study demonstrates that IMCgp100 induces broad immune responses that extend beyond the induction of CD8⁺ T cell‐mediated cytotoxicity. These findings are of particular importance because IMCgp100 is currently undergoing clinical trials as a single agent or in combination with check point inhibitors for patients with malignant melanoma.     

CCR4 is an up-regulated chemokine receptor of peripheral blood memory CD4+ T cells in Crohn's disease

Several chemokine receptors are expressed selectively on the surface of T cells depending on their polarization. The aim of this study was to characterize chemokine receptor expression in peripheral blood memory T cells in Crohn's disease (CD) and ulcerative colitis (UC), and to correlate the expression with disease activity. Peripheral blood mononuclear cells (PBMCs) were obtained from 24 patients with CD, 30 patients with UC, 24 normal controls and 10 disease controls. PBMCs were stained by anti-CCR3, CCR4, CCR5, CXCR3, CD4, CD8, CD45RO and beta 7 integrin, and the expression of the chemokine receptors were determined by flow cytometry. CCR4 expression on memory T cells was significantly lower in UC than in CD or normal controls, and that of memory CD4+ T and beta 7(high) memory CD4+ T cells was significantly higher in CD than in UC or normal controls. CCR4 expression on memory CD4+ T cells exhibited significant positive correlation with disease activity in CD, and this decreased significantly after treatment. Such a decrease was not found in the disease controls. CCR5 and CXCR3 expression on memory CD8+ T cells was significantly lower in CD than in normal controls. CXCR3 expression on beta 7(high) memory CD4+ T and CXCR3 expression on memory CD8+ T cells were lower in UC than in normal controls. These findings suggest that in peripheral blood memory T cells, chemokine receptor expression is different between CD and UC. Enhancement of CCR4 and suppression of CCR5 and CXCR3 seem to be the characteristic chemokine receptor profile in peripheral blood memory T cells of CD.