CD4+CD25+和CD8+调节性T细胞的作用机制

调节性T细胞（Treg）主要在机体免疫系统中发挥负向调节作用,既能抑制不恰当的免疫反应,又能限定免疫应答的范围、程度及作用时间,对CD4^＋和CD8^＋效应性T淋巴细胞的增殖起抑制作用,因此在移植物抗宿主病、自身免疫病、过敏性疾病等的发病机制和临床治疗中有潜在的应用价值.本文重点介绍CD4^＋CD25^＋Treg和CD8^＋Treg的作用机制,并简述调节性T细胞研究面临的挑战与展望.     

Regulatory CD4+CD25+ T cells restrict memory CD8+ T cell responses

CD4+ T cell help is important for the generation of CD8+ T cell responses. We used depleting anti-CD4 mAb to analyze the role of CD4+ T cells for memory CD8+ T cell responses after secondary infection of mice with the intracellular bacterium Listeria monocytogenes, or after boost immunization by specific peptide or DNA vaccination. Surprisingly, anti-CD4 mAb treatment during secondary CD8+ T cell responses markedly enlarged the population size of antigen-specific CD8+ T cells. After boost immunization with peptide or DNA, this effect was particularly profound, and antigen-specific CD8+ T cell populations were enlarged at least 10-fold. In terms of cytokine production and cytotoxicity, the enlarged CD8+ T cell population consisted of functional effector T cells. In depletion and transfer experiments, the suppressive function could be ascribed to CD4+CD25+ T cells. Our results demonstrate that CD4+ T cells control the CD8+ T cell response in two directions. Initially, they promote the generation of a CD8+ T cell responses and later they restrain the strength of the CD8+ T cell memory response. Down-modulation of CD8+ T cell responses during infection could prevent harmful consequences after eradication of the pathogen.     

哮喘患儿CD8+CD28+、CD8+CD28-T淋巴细胞检测及其临床意义

目的通过对哮喘患儿CD4、CD8和CD28的联合检测,探讨哮喘患儿淋巴细胞免疫功能状态及其临床意义.方法采用流式细胞术检测哮喘患儿外周血的总T细胞(CD3+)、辅助/诱导T淋巴细胞(CD4+)、抑制/细胞毒T淋巴细胞(CD8+)、细胞毒T细胞(CD8+CD28+)、抑制T细胞(CD8+CD28-).结果哮喘患儿组与对照组比较;CD3+、CD4+、CD8+CD28-细胞均低于对照组(P＜0.01,P＜0.05),CD8+CD28+细胞增高(P＜0.05),CD4+/CD8+比值、CD8+与对照组比较均无显著性差异(P＞0.05).结论哮喘患儿存在T淋巴细胞亚群免疫功能紊乱,而CD8+CD28+、CD8+CD28-T细胞失衡可能是导致机体免疫功能紊乱的主要因素.     

CD4+CD25+ T cells regulate virus-specific primary and memory CD8+ T cell responses

Naturally occurring CD4+CD25+ regulatory T cells appear important to prevent activation of autoreactive T cells. This article demonstrates that the magnitude of a CD8+ T cell-mediated immune response to an acute viral infection is also subject to control by CD4+CD25+ T regulatory cells (Treg). Accordingly, if natural Treg were depleted with specific anti-CD25 antibody before infection with HSV, the resultant CD8+ T cell response to the immunodominant peptide SSIEFARL was significantly enhanced. This was shown by several in vitro measures of CD8+ T cell reactivity and by assays that directly determine CD8+ T cell function, such as proliferation and cytotoxicity in vivo. The enhanced responsiveness in CD25-depleted animals was between three- and fourfold with the effect evident both in the acute and memory phases of the immune response. Surprisingly, HSV infection resulted in enhanced Treg function with such cells able to suppress CD8+ T cell responses to both viral and unrelated antigens. Our results are discussed both in term of how viral infection might temporarily diminish immunity to other infectious agents and their application to vaccines. Thus, controlling suppressor effects at the time of vaccination could result in more effective immunity.     

CD4+CD25+调节性T细胞的研究进展

CD4^＋CD25^＋调节性T细胞（regulatory T cell,Treg）具有维持自身免疫耐受和调节免疫应答的功能,其功能紊乱或数目下降是导致自身免疫性疾病的重要原因之一。近年来,研究发现Foxp3在调控CD4^＋CD25^＋Treg细胞的发育和功能上起着重要作用。本文就CD4^＋CD25^＋Treg细胞的免疫抑制机制、Foxp3在其发育和功能上的作用、IL-2和细胞毒性T淋巴细胞相关抗原4（CTLA-4）等对其产生、维持及活化的作用等方面作一综述。     

CD4^＋CD25^＋调节性T细胞与自身免疫病

目的:CD4 CD25 调节性T细胞是一群具有免疫调节或免疫抑制功能的细胞。越来越多的实验证明,CD4 CD25 调节性T细胞在维持外周免疫耐受中起重要作用,这种T细胞的数量减少或功能缺失可导致自身免疫性疾病的发生。本文就CD4 CD25 调节性T细胞及其在自身免疫性疾病中作用的研究进展做一综述。资料来源:应用计算机检索CNKI、Medline、EMCC数据库和手工检索2006-2007年的相关文献。检索词为"CD4 CD25 T调节性细胞,自身免疫病,免疫耐受,CD4 CD25 regulatory T cell,Treg,autoimmune disease,immune tolerance"。资料选择:检索范围包括临床研究(不限研究对象的年龄、性别、种族)和基础研究,不限体内和体外研究。资料提炼:共收集到相关文献675篇,选择其中33篇英文文献进行重点阅读和分析。资料综合:CD4 CD25 调节性T细胞具有免疫抑制功能,在机体的免疫调节中发挥重要作用。与其免疫调节功能相关的杀伤性T细胞淋巴细胞相关抗原4、CD45RO、糖皮质激素诱导的肿瘤坏死因子受体、淋巴细胞的无能相关基因等细胞表面分子和白细胞介素2、白细胞介素10、白细胞介素4、转化生长因子β等细胞因子的研究不断深入。此外,CD4 CD25 调节性T细胞功能的发挥还与FOXP3的表达密切相关。CD4 CD25 调节性T细胞数量的减少、抑制功能的受损和(或)细胞表面分子表达的缺陷可能导致1型糖尿病、多发性硬化和炎症性肠病等多种自身免疫病的发生。结论:CD4 CD25 调节性T细胞主要通过细胞接触依赖机制和抑制性细胞因子依赖机制发挥免疫抑制效应。其数量的减少、功能的受损和(或)表面分子表达的缺陷与自身免疫病的发生发展密切相关。     

Radiotherapy-exposed CD8+ and CD4+ neoantigens enhance tumor control

Neoantigens generated by somatic nonsynonymous mutations are key targets of tumor-specific T cells, but only a small number of mutations predicted to be immunogenic are presented by MHC molecules on cancer cells. Vaccination studies in mice and patients have shown that the majority of neoepitopes that elicit T cell responses fail to induce significant antitumor activity, for incompletely understood reasons. We report that radiotherapy upregulates the expression of genes containing immunogenic mutations in a poorly immunogenic mouse model of triple-negative breast cancer. Vaccination with neoepitopes encoded by these genes elicited CD8⁺ and CD4⁺ T cells that, whereas ineffective in preventing tumor growth, improved the therapeutic efficacy of radiotherapy. Mechanistically, neoantigen-specific CD8⁺ T cells preferentially killed irradiated tumor cells. Neoantigen-specific CD4⁺ T cells were required for the therapeutic efficacy of vaccination and acted by producing Th1 cytokines, killing irradiated tumor cells, and promoting epitope spread. Such a cytotoxic activity relied on the ability of radiation to upregulate class II MHC molecules as well as the death receptors FAS/CD95 and DR5 on the surface of tumor cells. These results provide proof-of-principle evidence that radiotherapy works in concert with neoantigen vaccination to improve tumor control.     

阵发性睡眠性血红蛋白尿症患者骨髓CD34+CD59+细胞与CD34+CD59-细胞生物学性能的研究

目的 探讨阵发性睡眠性血红蛋白尿症(PNH)患CD34^ CD59^ 细胞的特性及PNH克隆呈优势造血的可能原因，以探索PNH发病的内在机制。方法 用免疫磁珠吸附法富集纯化CD34^ 细胞，再用流式细胞仪分选出PNH患的CD34^ CD59^ 细胞、CD34^ CD59^ 细胞及正常对照CD34^ 细胞。分别进行体外扩增液体培养2周，并对扩增前、后的细胞进行半固体培养。结果 ①PNH患CD34^ CD59^ 细胞与正常对照CD34^ 细胞形成集落形成单位(CFU)均在第7天达到扩增高峰，并且扩增后的细胞仍能保持CD59抗原，无GPI锚连蛋白的丢失。②正常对照的CD34^ 细胞在生存、增殖、形成CFU及扩增能力上均明显强于FHN患的CD34^ CD59^ 细胞及CD34^ CD59^-细胞.③PNH患CD34^ CD59^ 细胞及CD34^ CD59^ 细胞体外半固体培养，其形成CFU的能力无明显差异。④PNH患CD34^ CD59^ 细胞及CD34^ CD59^ 细胞在SCF IL3 IL6 FL Tpo及SCF IL3 IL6 FL Tpo Epo组合下液体培养，其生存、增殖、扩增等能力上均无明显差异。但在SCF IL3 IL6 FL Tpo Epo GM-CSF组合下液体培养，CD34^ CD59^ 细胞的生存、增殖、扩增能力均明显强于CD34^ CD59^ 细胞。结论 ①正常对照的CD34^ 细胞在生存、增殖、形成CFU及扩增能力上均明显强于PNH患的CD34^ CD59^ 细胞。②PNH患CD34^ CD59^ 细胞及CD34^ CD59^ 细胞体外半固体培养，以及在SCF IL3 IL6 LF Tpo及SCF IL3 IL6 FL Tpo Ep组合下液体培养，其生存、增殖、扩增等能力上均无明显差异，说明CD34^ CD59^ 细胞在造血能力上并无内在的优势。GM—CSF或许是使PNH克隆呈造血优势的原因之一。     

支气管哮喘患儿外周血淋巴细胞CD19~+CD23~+和CD4~+CD25~+的表达及意义

目的探讨支气管哮喘患儿外周血淋巴细胞CD19＋CD23＋和CD4＋CD25＋的表达及意义。方法采用流式细胞分析技术及免疫化学发光法分别检测34例哮喘发作期（哮喘发作组）和32例哮喘缓解期（哮喘缓解组）外周血CD19＋CD23＋表达率、CD4＋CD25＋表达率和血清总IgE水平,并与25例体检儿童（对照组）进行比较。结果哮喘发作组外周血CD19＋CD23＋表达率为（19.31±9．08）％分别高于哮喘缓解组（8．63±3．54）％和对照组;哮喘发作组CD4＋CD25＋表达率为（2．79±1．69）％和哮喘缓解组为（3.36±1．17）％均低于对照组;哮喘发作组IgE水平为（177．01±90．38）IU/ml和哮喘缓解组为（160．76±77．54）IU／ml均高于对照组．三组的差异均有统计学意义（F分别=36．62、24．67、24．35,P均〈0．05）。CD19＋CD23＋表达率与IgE呈正相关,CD4＋CD25＋表达率和IgE呈明显负相关,CD19＋CD23＋表达率和CD4＋CD25＋表达率亦呈明显负相关,差异均有统计学意义（r分别：0．22、-0．41、-0．34,P均〈0．05）。结论哮喘急性发作时外周血CD19＋CD23＋和CD4＋CD25＋改变明显。     

CD4+ but not CD8+ cells are essential for allorejection

The generation of knockout mice with targeted gene disruption has provided a valuable tool for studying the immune response. Here we describe the use of CD4 and CD8 knockout mice to examine the role of CD4+ and CD8+ cells in initiating allotransplantation rejection. Pretreatment with a brief course of depletive anti-CD4 monoclonal antibody therapy allowed permanent survival of heart, but not skin, allografts transplanted across a major histocompatibility barrier. However, skin as well as heart grafts were permanently accepted in the CD4 knockout mice. Transfer of CD4+ cells into CD4 knockout recipient mice 1 d before skin engraftment reconstituted rejection, demonstrating that CD4+ cells are necessary for initiating rejection of allogeneic transplants. Major histocompatibility complex disparate heart and skin allografts transplanted into CD8 knockout recipients were rejected within 10 d. This study demonstrates that CD4+ but not CD8+ T cells are absolutely required to initiate allograft rejection.     

CD133+CD34+ and CD133+CD38+ blood progenitor cells as predictors of platelet engraftment in patients undergoing autologous peripheral blood stem cell transplantation

BackgroundHematopoietic stem cells (HSC) have been characterized by CD34+ expression and an adequate dose of CD34+ cells is associated with a complete engraftment. CD133 is a more specific marker of HSC.Materials and methodsWe studied the relationship between graft content of CD34+, CD133+, and CD38+ cells and trilineage engraftment after autologous stem cell transplantation in patients with different hematological disorders. Blood samples were obtained before and after mobilization with recombinant granulocyte-colony stimulating factor (G-CSF, 16 μg/kg), from apheresis collections, and after transplantation.ResultsCell subsets were quantified by flow cytometry, and the dose of each population infused was correlated with success of engraftment. G-CSF induced mobilization of CD133+CD38+ cells (12.6-fold) and CD133+CD34+ cells (14.7-fold). A correlation was observed between the infused dose of CD133+CD34+ and CD133+CD38+ cells and platelet engraftment.ConclusionCD133+CD34+ and CD133+CD38+ cells were mobilized with G-CSF and these cell subsets were correlated with platelet engraftment.     

CD4+CD25+ regulatory T cells suppress allograft rejection mediated by memory CD8+ T cells via a CD30-dependent mechanism

CD4(+)CD25(+) regulatory T (Treg) cells suppress naive T cell responses, prevent autoimmunity, and delay allograft rejection. It is not known, however, whether Treg cells suppress allograft rejection mediated by memory T cells, as the latter mount faster and stronger immune responses than their naive counterparts. Here we show that antigen-induced, but not naive, Treg cells suppress allograft rejection mediated by memory CD8(+) T cells. Suppression was allospecific, as Treg cells induced by third-party antigens did not delay allograft rejection. In vivo and in vitro analyses revealed that the apoptosis of allospecific memory CD8(+) T cells is significantly increased in the presence of antigen-induced Treg cells, while their proliferation remains unaffected. Importantly, neither suppression of allograft rejection nor enhanced apoptosis of memory CD8(+) T cells was observed when Treg cells lacked CD30 or when CD30 ligand-CD30 interaction was blocked with anti-CD30 ligand Ab. This study therefore provides direct evidence that pathogenic memory T cells are amenable to suppression in an antigen-specific manner and identifies CD30 as a molecule that is critical for the regulation of memory T cell responses.     

Interferon gamma selectively inhibits very primitive CD342+CD38- and not more mature CD34+CD38+ human hematopoietic progenitor cells

To assess the effects of interferon gamma (IFN-gamma) on very primitive hematopoietic progenitor cells, CD34(2+)CD38- human bone marrow cells were isolated and cultured in a two-stage culture system, consisting of a primary liquid culture phase followed by a secondary semisolid colony assay. CD34(2+)CD38- cells needed at least the presence of interleukin 3 (IL-3) and kit ligand (KL) together with either IL-1, IL-6, or granulocyte-colony-stimulating factor (G-CSF) in the primary liquid phase in order to proliferate and differentiate into secondary colony- forming cells (CFC). Addition of IFN-gamma to the primary liquid cultures inhibited cell proliferation and generation of secondary CFC in a dose-dependent way. This was a direct effect since it was also seen in primary single cell cultures of CD34(2+)CD38- cells. The proliferation of more mature CD34+CD38+ cells, however, was not inhibited by IFN-gamma, demonstrating for the first time that IFN-gamma is a specific and direct hematopoietic stem cell inhibitor. IFN-gamma, moreover, preserves the viability of CD34(2+)CD38- cells in the absence of other cytokines. IFN-gamma could, therefore, play a role in the protection of the stem cell compartment from exhaustion in situations of hematopoietic stress and may be useful as stem cell protecting agent against chemotherapy for cancer.     

CD3+CD16+NK1.1+B220+ large granular lymphocytes arise from both alpha- beta TCR+CD4-CD8- and gamma-delta TCR+CD4-CD8- cells

Cultivation of CD4-CD8- double negative (DN) mouse thymocytes and splenocytes with recombinant interleukin 2 (IL2) in the absence of other stimulation results in the generation of DN- CD3/TCR+CD16+NK1.1+B220+ large granular lymphocytes (LGL). Purified DN alpha-beta TCR+ thymocytes and splenocytes are CD16+IL2R alpha-IL2R beta+NK1.1+B220-CD5high. These cells are unique in that they express both CD16 and T cell receptor (TCR) which are usually mutually exclusive. In addition, they express the natural killer (NK) marker, NK1.1. Cultivation of these cells with IL2 for several days results in the generation of DN alpha-beta TCR+CD16+NK1.1+B220+CD5- LGL, suggesting that DN alpha-beta TCR+ cells in thymus and spleen are the precursors of the DN LGL reported previously. DN gamma-delta TCR+CD16- NK1.1-B220-CD5high thymocytes and splenocytes also give rise to DN gamma-delta TCR+CD16+NK1.1+B220+CD5- LGL which, as shown previously with DN alpha-beta TCR+ LGL cells, are cytotoxic against NK-sensitive YAC-1 cells. Cytotoxic activity is also induced through either CD16 or the gamma-delta TCR. DN alpha-beta TCR+ and DN gamma-delta TCR+ LGL cells are thus similar in phenotype to TCR- NK cells. DN alpha-beta TCR+ thymocytes express low levels of the gamma subunit of the high affinity immunoglobulin E receptor (Fc epsilon RI gamma) molecule, an essential component of CD16 expression. Fc epsilon RI gamma expression is greatly enhanced after cultivation with IL2, resulting in a higher surface expression of CD16. In contrast to DN alpha-beta TCR+ thymocytes, DN gamma-delta TCR+ thymocytes do not express detectable CD16 or Fc epsilon RI gamma mRNA but expression of both is induced by cultivation with IL2, leading to the expression of CD16 on the surface. Whereas CD16 molecules on both DN alpha-beta TCR+ and DN gamma-delta TCR+ LGL are associated with only Fc epsilon RI gamma homodimers, the TCR on these cells are associated with an Fc epsilon RI gamma homodimer and/or CD3 zeta-Fc epsilon RI gamma heterodimers. These results demonstrate that the Fc epsilon RI gamma subunit is a component of the TCR in a fraction of T lineage cells.     

CD4^＋CD25^＋T细胞的扩增及其功能分析

背景:CD4+CD25+T细胞增殖能力低,且在人外周血中仅占单个核细胞的4%左右.若能在体外高效扩增CD4+CD25+T细胞,并保持其免疫调节特性,将会对临床移植产生积极的影响.目的:观察C57BL/6小鼠来源的CD4+CD25+T细胞体外增殖情况及其扩增后的功能变化.设计、时间及地点:细胞学体外观察,于2007-10/2008-05在南方医科大学珠江医院血液科完成.材料:SPF级C57BL/6及BALB/C雄性小鼠购白南方医科大学动物所.小鼠白血病细胞EL9611由珠江医院血液科惠赠.方法:利用免疫磁珠法分选小鼠CD4+CD25+T细胞;以抗鼠CD3ε单抗、抗鼠CD28单抗、鼠重组白细胞介素2及辐射过的BALB/C小鼠脾细胞为共刺激因子,通过实时定量RT-PCR检测扩增后CD4+CD25+T细胞FoxP3基因mRNA表达变化,以确定增殖效率;3H-TdR掺入法检测扩增后的CD4+CD25+T细胞对CD4+CD25T细胞增殖的影响:LDH释放法检测扩增后的CD4+CD25+T细胞对CD4+CD25T细胞杀伤小鼠白血病细胞EL9611的影响,以CD4+CD25T细胞为效应细胞,以EL9611细胞为靶细胞.结果:经免疫磁珠分选可获得高纯度及较强活性的CD4+CD25+T细胞.扩增后CD4+CD25+T细胞FoxP3基因mRNA的表达平均为扩增前的5.46倍,最高可达14.39倍.扩增后CD4+CD25+T细胞可明显抑制CD4+CD25T细胞的增殖,且随着CD4+CD25+T细胞数的增加,这种抑制增殖的能力也逐渐增强,当两者比例为1:1时抑制率最大,达62.05%.与单纯CD4+CD25+T细胞对EL9611细胞杀伤率比较,效靶比为10:1时扩增后的CD4+CD25+T细胞联合CD4+CD25-T细胞的杀伤率无明显变化(t=2.199,P>0.05):效靶比为5:1时扩增后的CD4+CD25+T细胞联合CD4+CD25-T细胞的杀伤率则明显降低(t=5.839,P<0.05).结论:单抗加异源性抗原能宵效扩增CD4+CD25+T细胞;扩增后的CD4+CD25+T细胞比新鲜分离的CD4+CD25+T细胞能更有效地抑制CD4+CD25-T细胞的增殖,其对CD4+CD25-T细胞杀伤白血病细胞的作用则取决于其与CD4+CD25-T细胞的相对比例.     

淋巴细胞CD3~+、CD4~+、CD8~+亚群检测在早发型新生儿败血症诊断中的价值

目的探讨早发型新生儿败血症诊断中,淋巴细胞CD3~+、CD4~+、CD8~+百分比检测的价值。方法将2014年1月至2015年6月出生,7d内发病,疑似感染的患儿纳入本研究,入院24h内采集静脉血,检测CD3~+、CD4~+、CD8~+淋巴细胞百分比,C反应蛋白(CRP)及血常规,在抗菌药物使用前做血培养。将其中血培养证实为早发型新生儿败血症的足月新生儿作为败血症组,血培养阴性的作为局部感染组。同时选择同期因高胆红素血症(排除感染等因素所致)而住院的足月新生儿作为非感染组。采用流式细胞仪对上述患儿标本进行检测,观察并比较3组间淋巴细胞亚群CD3~+、CD4~+、CD8~+百分比。结果败血症组CD3~+[(40.3±10.6)%],CD4~+[(28.6±11.2)%],CD8~+[(10.8±2.6)%]低于局部感染组的CD3~+[(64.8±9.8)%],CD4~+[(48.9±10.2)%],CD8~+[(17.6±5.6)%]和非感染组的CD3~+[(62.6±11.6)%]、CD4~+[(46.4±13.6)%]、CD8~+[(16.5±7.3)%],差异有统计学意义(P0.05),局部感染组的CD3~+、CD4~+、CD8~+与非感染组之间比较,差异无统计学意义(P0.05)。结论CD3~+、CD4~+、CD8~+百分比可以作为诊断早发型新生儿败血症的指标。