CD4+CD25+调节性T细胞研究进展

CD4+CD25+调节性T细胞是调节性T细胞的亚群之一,主要来源于胸腺,具有多种独特的特征,包括可识别自身抗原肽、分泌抑制性细胞因子等.其功能是通过抑制自身反应性T细胞的免疫反应、抑制传统T细胞的活化以及促进一些抑制性细胞因子的分泌等,在维持机体内环境的稳定、肿瘤免疫监测、诱导移植耐受以及自身免疫性疾病的发生中发挥重要作用.     

CD4+CD25+T细胞:一类新被认识的免疫调节细胞

CD4+CD25+T细胞是最近才被认识的一类免疫调节细胞,在胸腺产生,主要发挥抑制性免疫调节功能,表达IL-10mRNA,细胞表面表达IL-2受体α链(CD25),本身不产生IL-2,但在体内、外增殖需要外源性IL-2,在体外为无能细胞(anergy cell),CD4+CD25+T细胞发挥免疫抑制作用是通过细胞-细胞接触依赖方式而非细胞因子依赖方式,CD4+CD25+T细胞在调控自身免疫性疾病的发生、炎症反应和T细胞稳态中发挥重要作用.本文拟对CD4+CD25+T细胞的生物学特性及其应用研究的最新进展作一综述.     

树突状细胞扩增抗原特异性CD4+ CD25+调节性T细胞研究进展

CD4+CD25+调节性T细胞(Tr)是同时具有免疫低反应性和免疫抑制性功能两大特征的T细胞.研究证实,CD4+ CD25+ Tr在抑制器官特异性自身免疫性疾病及GVHD是抗原特异性的,因此,应用器官特异性而不是多克隆性的Tr将大大促进以Tr为基础的免疫治疗.而具有调节活性的CD4+ CD25+ Tr仅占人类外周血CIM+ T细胞的1%～2%,因此,研究体外大量扩增的方法 对于以Tr基础的治疗至关重要.研究表明,树突状细胞(DC)作为机体强有力的专职抗原递呈细胞可以扩增具有抗原特异性的CD4+ CD25+ Tr且能增加后者的抑制活性,这为治疗自身免疫性疾病及GVHD提供了新的治疗前景.     

抗原特异性初始CD4+T细胞的体内分化及特性

为了探讨抗原特异性CD4+T细胞在体内的分裂、表型、Th1细胞因子的产生和组织器官的分布。将CFSE标记的抗原特异性初始CD4+T细胞静脉被动输给小鼠后,进行免疫,3d后处死小鼠取其脾脏、淋巴结和肺组织,分离单个核细胞,利用流式细胞计数仪在单个细胞水平上,观察细胞的分裂、表型、Th1细胞因子的产生和组织分布。结果显示在没有抗原刺激的情况下,未见初始CD4+T细胞分裂,其主要分布于淋巴结和脾脏。当受到抗原刺激后,CD4+T细胞分裂1～5次,主要分布于脾脏和肺组织,CD25的表达增加,CD62L的表达随着细胞分裂次数的增加而减少。IL-12促进CD25的表达和细胞的分裂。促进Th1细胞的分化和IFN-γ的表达。研究的结果提示,在体内,当CD4+T细胞活化后,主要分布于脾和非淋巴组织发挥其免疫效应。     

小鼠脾细胞CD4+CD25+调节性T细胞的表型特征

观察CD4+CD25+T和CD4+CD25-T细胞的表型和细胞因子的表达。自小鼠脾脏制备单个细胞悬液,分离CD4+T细胞、CD4+CD25+和CD4+CD25-T细胞,进行细胞表面标记,激活后进行细胞内细胞因子染色,利用流式细胞仪在单个细胞水平上分析细胞表面分子、转录因子和细胞因子表达之间的关系。结果:在CD4+T细胞中,约有7.8%的细胞同时表达CD25分子。与CD4+CD25-T细胞相比,CD4+CD25+T细胞CD44的表达略有增加,CD45RB的表达明显下降,CTLA-4和Foxp3明显增加。以同时表达CTLA-4和Foxp3的细胞为主,其次为单独表达Foxp3的细胞。细胞因子的研究结果表明,与CD4+CD25-T细胞相比,CD4+CD25+T细胞IL-2、IFN-γ明显减少,而只产生IL-10的细胞略有增加。CD4+CD25+调节性T细胞无论在表型、转录因子的表达以及细胞因子表达方面均于非调节性T细胞不同。     

CD4+CD25+T细胞与移植免疫耐受

调节性T细胞是机体维持自身耐受的重要组成部分.CD4+CD25+T细胞以持续高表达CD25为特征,可通过细胞间直接接触或分泌TGF-β、IL-10来发挥抑制功能.它广泛参与自身免疫耐受、肿瘤免疫、移植免疫.现就其发育、特性、发挥功能的机制以及在移植免疫耐受中的作用和应用前景作一综述.     

风湿性心脏病患者的CD4~+CD25~+调节性T细胞及细胞因子的改变及意义

目的:探讨相较于正常人,风湿性心脏病(RHD)患者的血液细胞因子及CD4+CD25+调节性T细胞的改变及意义。方法:分析2012年4月至2013年7月在我院接受住院治疗的RHD患者(观察组)的临床资料,对照组是从我院体检中心选取的健康体检人员,对两组研究对象外周血标本中的转化生长因子-β1(TGF-β1)、肿瘤坏死因子-α(TNF-α)、白细胞介素10(IL-10)、白细胞介素6(IL-6)及CD4+CD25+调节性T细胞表达水平进行检测和比较。结果:本研究共纳入受试者76例,其中观察组患者40例,对照组36例。观察组患者的CD4+CD25+T占淋巴细胞比例(t=17.37,P0.01)、CD4+CD25+Foxp3+Treg占CD4+T比例(t=9.224,P0.01)均显著低于对照组;观察组患者的TGF-β1(t=9.036,P0.01)、IL-10(t=12.11,P0.01)均显著低于对照组,而TNF-α(t=2.331,P=0.013)、IL-6(t=2.239,P0.01)水平则高于对照组,差异均有统计学意义。结论:RHD患者CD4+CD25+调节性T细胞水平明显降低,血液细胞因子如TGF-β1和IL-10也相应地出现下降。     

胃癌患者PBMCs中CD4+CD25+T细胞体外增殖及对CD4+CD25-T细胞增殖的影响

目的:探讨胃癌患者外周血单个核细胞（PBMCs）中的CD4+CD25+T细胞体外增殖及对CD4+CD25-T细胞增殖的影响。 方法:以免疫磁性分离方法 （MACS）分选出胃癌患者外周血单个核细胞中的CD4+CD25+T及CD4+CD25-T细胞后，用流式细胞仪分析细胞的纯度及活力；再以小鼠抗人CD3单抗、小鼠抗人CD28单抗及rh IL-2作为共刺激因子，观察与CD4+CD25-T细胞共培养时，CD4+CD25+T细胞对CD4+CD25-T细胞增殖的抑制效应。 结果:（1）分选后健康对照组及胃癌患者PBMC 中CD4+CD25+ T细胞纯度分别为83.8%±1.84%、84.13%±2.77％，两者相比，无显著差异（P＞0.05）;(2)经MACS 分选后正常对照组与胃癌患者CD4+CD25+ T细胞活力分别为98.52%±0.72%、97.80%±0.95%，两者相比，无显著差异（P＞0.05）；(3)无论是健康对照还是胃癌患者的CD4+CD25+T均具有明显抑制效应性T细胞如CD4+CD25-T细胞的增殖，随着CD4+CD25+T细胞数的增加，这种抑制增殖的能力也相应增加，当CD4+CD25+∶〖KG-*2〗CD4+CD25-T达 1∶〖KG-*2〗1时，抑制率最大达到50％。 结论:MACS分选法能够分选出高纯度及活力的CD4+CD25+T细胞，分选后CD4+CD25+T细胞在体外均能抑制CD4+CD25-T细胞增殖，且这种抑制效应呈一定效靶比关系。     

PGE_2调节CD4~+T细胞分化的研究进展

前列腺素(prostaglandin,PG)是花生四烯酸的小分子衍生物,在内分泌系统、心血管系统、生殖系统和神经系统中发挥多种生物学效应。PGE_2作为PG比较有代表性的一种亚型,是人体内重要的炎症介质,参与调节CD4~+T细胞的分化及相关细胞因子的分泌,从而影响CD4~+T细胞所介导的疾病的发生发展。本文就PGE_2及其对CD4~+T细胞亚群分化的调节作用进行综述。     

Foxp3和CD4+CD25+调节性T细胞研究进展

调节性T细胞是机体维持自身耐受的重要组成部分,其对免疫反应具有抑制效应,在体外增殖能力低,在免疫病理、移植物耐受、阻止自身免疫反应和维持机体免疫平衡方面都有一定作用.最近发现Foxp3在调控调节性T细胞的一重要亚群CD4+CD25+T细胞的发育上起很重要的作用.本文就CD4+CD25+T细胞特性、Foxp3在其发育和功能发挥中的作用以及其活性调节方面作一综述.     

CD38+ CD45RBlow CD4+ T cells: a population of T cells with immune regulatory activities in vitro

An antibody reactive with CD38 revealed both phenotypic and functional heterogeneity amongst CD45RB^low cells. Functional analysis of the CD38⁺ and CD38⁻ fractions showed that the latter contained T cells which responded to recall antigens and produced high levels of cytokine in response to polyclonal stimulation. In contrast, the CD38⁺ population failed to proliferate or to produce detectable levels of cytokines. Despite appearing unresponsive, the CD38⁺ population significantly inhibited anti-CD3-induced proliferation and cytokine secretion by the reciprocal CD38⁻ population. Immune suppression required stimulation through the TCR and was dependent on a physical interaction between regulatory and responding CD4⁺ populations. It did not involve killing of the responding T cells or secretion of IL-10 or TGF-β. Despite some similarities there is no direct correlation between the in vitro suppression characteristic of the CD38⁺ CD45RB^low subset and in vivo suppression which has been shown to be mediated by unseparated CD45RB^low CD4⁺ T cells. However, these results demonstrate that two functionally distinct subsets of T cells reside within the antigen-exposed or CD45RB^low CD4⁺ T cell population and are thus generated in vivo: (1) conventional memory T cells which proliferate and secrete cytokines in response to activation and (2) a population of regulatory T cells which inhibit T cell activation in vitro. Antibodies reactive with CD38 may provide a useful tool with which to study the role of these T cell subsets in the induction and regulation of the immune response.     

Spontaneous production of various cytokines except IL-4 from CD4+ T cells in the affected organs of sarcoidosis patients.

We investigated surface antigens and spontaneous cytokine production of T cells from bronchoalveolar lavage fluid (BALF) and aqueous humor (AH) from pulmonary sarcoidosis patients for a better understanding of the role of T cells in granuloma formation. The levels of CD3, CD11b, and CD28 antigen expression on freshly isolated T cells in the BALF of patients were significantly lower than those in peripheral blood lymphocytes (PBL) of either sarcoidosis patients or healthy donors (HD). In contrast, the levels of CD80 (B7/B7-1) and CD86 (B70/B7-2) antigen expression were significantly higher on these T cells and alveolar macrophages in the BALF of patients. Fifty-three T cell clones (TCC) established from the BALF and AH of the three sarcoidosis patients displayed primarily either CD4+ CD11b+ CD28+ or CD4+ CD11b- CD28- phenotypes. Most (61-90%) of these TCC spontaneously produced greater amounts of IL-1 alpha, IL-10, tumour necrosis factor (TNF), and granulocyte-macrophage colony-stimulating factor (GM-CSF) than did TCC from the PBL from sarcoidosis patients or HD (P < 0.05). Interferon-gamma (IFN-gamma), IL-6, and IL-2, but not IL-4, were also produced by 40-48% of these TCC. These results suggest that CD4+ T cells of the affected organs of sarcoidosis patients are activated and involved in the immunopathogenesis of sarcoidosis through production of various cytokines.     

A distinct role for ICOS-mediated co-stimulatory signaling in CD4+ and CD8+ T cell subsets

While the ligand of inducible co-stimulator (ICOS), B7 homologous protein, is widely expressed in somatic cells, B7-1 and B7-2 expression is mainly limited to lymphoid organs. Thus, the activation of T cells through ICOS without a CD28-mediated signal may occur in physiological situations. In order to gain a better understanding of the role of the ICOS co-stimulatory signal in immune responses, we studied the cellular response of T cells to beads coated with anti-ICOS or anti-CD28, plus sub-optimal anti-CD3 mAb. We demonstrate that while CD28 ligation induced expansion of both CD4+ and CD8+ populations, ICOS ligation only resulted in the expansion of CD8+ T cells, and induced apoptosis in the CD4+ T cell population. It was found that IL-2 is critically required for CD8+ T cell expansion triggered by ICOS ligation, whereas it had only a limited effect on the expansion of CD4+ T cells. This distinct reactivity of CD4+ and CD8+ T cell populations to exogenous IL-2 strongly correlates with the expression level of IL-2 receptor beta-chain, CD122, on T cells. Furthermore, we defined a small but distinct population of memory phenotype CD4+ T cells that constitutively express ICOS. Interestingly, while naive CD4+ T cells were unable to produce IL-2, ICOS-expressing T cells produced a substantial amount of IL-2 by stimulation with anti-ICOS/CD3 beads, suggesting that IL-2, which is indispensable for CD8+ T cell expansion, is produced by this ICOS-expressing T cell population. These results provide evidence indicating that the ICOS co-stimulatory signal plays a distinct role in the development of CD4+ and CD8+ T cell-mediated immune responses.     

间充质干细胞体外对ITP患者CD4+CD25+T细胞影响

目的:体外观察间充质干细胞(MSCs)对免疫性血小板减少症(ITP)患者CD4+ CD25+T细胞比例的影响.方法:采用Ficoll分离骨髓单个核细胞,通过体外培养,扩增出MSCs,通过Ficoll分离法和尼龙棉柱法获取正常人及ITP患者外周血T淋巴细胞,并应用流式细胞术检测T细胞中CD4+ CD25+T细胞比例;MSCs经丝裂霉素MMC处理后按不同数量(2×103、1×104、5×104个细胞/孔)接种培养板作为基底层细胞,然后分别接种体外分离纯化的异体ITP及正常人T淋巴细胞,于2、4、6天后各自收集T淋巴细胞及培养上清,用流式细胞术检测接种于骨髓MSCs的ITP患者CD4+ CD25+T细胞比例.结果:ITP患者外周血CD4+ CD25+T细胞数量及CD4+ CD25+/CD4+比值均明显低于正常对照组(P＜0.05);在PHA作用下,数量＞1×104的骨髓MSCs与T淋巴细胞共培养4天后,与正常对照组相比,MSCs可显著上调ITP患者及正常人T淋巴细胞中CD4+ CD25+T淋巴细胞比例及CD4+ CD25 +/CD4+比值(P＜0.05),且随MSCs量的增加,作用增强(P＜0.05).体外骨髓MSCs对ITP患者CD4+ CD25+T淋巴细胞具有上调作用,以上这种机制可使ITP患者的细胞因子及CD4+ CD25+T淋巴细胞逐渐接近于正常人但仍达不到正常人水平(P＜0.05).结论:MSCs在体外可能通过上调CD4+ CD25+调节性T细胞,进而诱导ITP患者免疫耐受形成.     

Comparative study of CD4 and CD45RO T cells and CD20 B cells in cerebrospinal fluid of syphilitic meningitis and tuberculous meningitis patients

This study was to investigate the differences of lymphocyte in the cerebrospinal fluid (CSF) of patients with syphilis meningitis (SM) and tuberculous meningitis (TBM) for new diagnostic insights. Totally, 79 cases of SM and 45 cases of TBM were enrolled. In the CSF, the CD4, CD45RO or CD20 positive lymphocytes were detected by immunohistochemistry. The proportion of CD4 T cells in the CSF lymphocytes in patients with SM was significantly higher than that in patients with TBM (p < 0.05). After medical therapy, there was a significantly decline trend of the CD4 T‐cell proportion in both groups (p < 0.05). The proportion of CD45RO T cells in CSF lymphocytes of patients with SM was less than that of patients with TBM (p < 0.05). After medical therapy, the positive ratio of CD45RO T cells was increased in the CSF of both group patients (p < 0.05). The proportion of CD20B cells in the CSF lymphocytes was not obviously different between the two groups during every stage. In conclusion, there are strong differences of CD4 and CD45RO T‐cell ratio, but not the CD20 B cells in the meningitis. CD4 and CD45RO T cells in CSF are a useful complement in differentially diagnosing SM and TBM; it contributes to further understand the pathogenesis and prognosis of SM and TBM.     

晚期肺癌患者血CD4+CD25+调节T细胞水平的变化

为探讨晚期肺癌患者CD 4CD 25去调节T细胞水平的变化及其与其它T细胞亚群和NK细胞的相互关系,对86例肺癌组患者和64名对照组测定和比较CD 4CD 25调节T细胞、T细胞亚群(CD 3、CD 4、CD 8、CD 8CD 28)和NK细胞的水平,探讨其临床意义.CD 4CD 25细胞和T细胞亚群均用流式细胞仪检测.结果表明,晚期肺癌患者血CD 4CD 25细胞明显高于对照组(18.4%±6.2%vs7.1%±0.4%,P<0.01),CD 4细胞、CD 8CD 28细胞和NK细胞明显低于对照组(32.4%±8.7%vs44.9%±8.4%,P<0.01;7.4%±3.5%vs16.5%±2.7%,P<0.01;10.2%±4.1%vs18.5%±7.2%,P<0.01),CD 8细胞明显高于对照组(36.7%±7.5%vs31.8%±5.1%,P<0.01).CD 4CD 25细胞与CD 8CD 28细胞、NK细胞呈明显负相关.表明CD 4CD 25细胞增多是晚期肺癌患者免疫功能紊乱的一个证据.     

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.     

T细胞疫苗免疫前后外周血CD4~ 和CD8~ T细胞变化的分析

目的 观察T细胞疫苗免疫前后外周血CD4~+和CD8~+T细胞的变化情况,探讨T细胞疫苗诱导特异性免疫耐受的作用及其机理。方法 制备针对Wistar大鼠的SD大鼠T细胞疫苗,用制备好的T细胞疫苗去免疫正常的SD大鼠,同时设特异性抗原对照组和空白对照组。于免疫前和免疫后规定时点分别进行单向混合淋巴细胞反应(MTT法),于相同时点通过流式细胞分析对外周血CD4~+和CD8~+T细胞进行检测。结果 在T细胞疫苗组,平均OD值免疫后比免疫前显著降低(P<0.01)CD4/CD8比值免疫后比免疫前显著降低(P<0.05);在特异性抗原对照组,免疫后的OD值显著高于免疫前(P<0.01),同时CD4/CD8比值于免疫后显著增高(P<0.05);空白对照组各时点各指标比较无显著差异(P>0.05)。结论T细胞疫苗可以诱导同种抗原特异性免疫耐受,CD4~+反应性T细胞克隆与CD8~+抗独特型T细胞克隆相对比例优势的转换可能在T细胞疫苗诱导的免疫耐受形成中发挥关键作用。