大鼠CD4~＋CD25-T细胞的Foxp3基因转染及其表达

背景：调节性T细胞在维持机体免疫应答稳态和免疫耐受方面具有非常重要的作用,但外周血中CD4＋CD25＋调节性T细胞含量极低,且增殖能力较差。目的：以携带Foxp3基因的慢病毒EGFP＋载体转染大鼠CD4＋CD25-T细胞,观察其在大鼠CD4＋CD25-T细胞中的表达。方法：以免疫磁珠两步法分选大鼠CD4＋CD25-T细胞,用携带大鼠Foxp3基因的慢病毒载体体外转染分选的细胞,以转染Foxp3基因的CD4＋CD25-T细胞为实验组,EGFP空白质粒组及CD4＋CD25-T细胞为阴性对照组,CD4＋CD25＋T细胞为阳性对照组。荧光显微镜和RT-PCR分别从蛋白和mRNA水平检测Foxp3基因的表达。结果与结论：成功完成了免疫磁珠的分选,获得了纯度较高的CD4＋CD25-T细胞和CD4＋CD25＋T细胞,细胞存活率为（94±2）%,慢病毒转染的CD4＋CD25-T细胞高表达Foxp3基因。表明以携带Foxp3基因的慢病毒载体系统可有效介导Foxp3基因在大鼠CD4＋CD25-T细胞中高表达。     

致敏小鼠CD4~+ CD25~+调节性T细胞磁珠分选及体外扩增

本研究探讨致敏小鼠CD4+ CD25+调节性T细胞的分选及体外扩增。流式细胞术检测致敏小鼠及正常小鼠体内CD4+ CD25+ Treg细胞水平,免疫磁珠分选方法从小鼠脾细胞中分选出CD4+T细胞、CD4+ CD25+ Treg细胞和CD4+ CD25-T细胞,负载抗CD3/CD28单克隆抗体MACSiBead联合IL-2共同刺激CD4+ CD25+ Treg细胞进行体外扩增培养,用0.4%台盼蓝染色并计数检测细胞的活性,流式细胞术检测分选后细胞纯度、主要表面标记及Foxp3基因的表达。结果表明:致敏小鼠体内CD4+ CD25+ Treg水平较正常小鼠升高(P<0.05)。分选出CD4+ CD25+ Treg细胞纯度平均达到87%,细胞活性大于97%,高表达Foxp3基因。体外扩增2周后细胞数扩增倍数能够达到42倍,CD4+ CD25+ Treg细胞所占比例为85.32%,Foxp3表达由(76.92±1.72)%稍下降至(75.33±2.11)%(P>0.05)。结论:免疫磁珠分选法能够分选出高纯度的CD4+ CD25+ Treg细胞,该分选方法不影响分选靶细胞的细胞活力;体外成功扩增了CD4+ CD25+ Treg细胞,扩增后的CD4+ CD25+ Treg细胞表面标记及Foxp3基因表达无明显改变。     

自身失活型慢病毒载体介导的鼠基因工程调节性T细胞的制备和特性研究

目的 制备自身失活型慢病毒载体为基础的鼠基因工程调节性T细胞(Treg细胞),检测其表型变化,并观察其增殖能力及免疫抑制能力.方法 构建含鼠Foxp3基因及内部核糖体进入位点序列(IRES)和绿色荧光蛋白基因(GFP)的双顺反子自身失活型慢病毒载体.采用脂质体转染法将慢病毒载体三质粒转染293T细胞,经共培养法感染免疫磁珠分离的小鼠CD4+CD25-T细胞,流式细胞术(FCM)检测基因转染效率及细胞Foxp3、CD25、GITR、CTLA-4的表达,CCK-8法、ELISA法检测其增殖、免疫抑制能力及细胞因子分泌的变化.结果 成功构建了慢病毒表达质粒pXZ208-IRES-GFP、pXZ208-Foxp3-IRES-GFP,包装的重组慢病毒滴度达106IU/ml.以pXZ208-IRES-GFP为阴性对照组,共培养法感染CD4+CD25-T细胞,实验组细胞Foxp3、CD25、CTLA-4、GITR表达升高.在抗CD3ε单抗、抗原呈递细胞存在条件下,实验组细胞增殖能力及IL-2、IL-4、IL-10和IFN-γ的分泌均低于阴性对照组(P<0.01);且该细胞可显著抑制CD+CD25-T细胞的增殖.结论 成功构建了自身失活型慢病毒载体介导的鼠基因工程Treg细胞;基因工程Treg细胞具有与CD4+CD25+Treg细胞相似的表型及低增殖性和免疫抑制性.     

小鼠调节性T细胞的CD4+ CD25+ CD127low/-标记分析

新的特异性细胞表面标记的发现是提高调节性T细胞(Treg)测量和分选技术的重要环节,Foxp3是公认的天然Treg的标记,却不能作为分选细胞的标记,CD127是新发现低表达于Treg细胞表面的标记。本实验测定CD4+CD25+CD127low/-和CD4+CD25+Foxp3+标记的小鼠外周血及脾脏Treg细胞的数量,并测定CD4+CD25+CD127low/-细胞内Foxp3转录因子的表达水平,分析CD4+CD25+CD127low/-标记在小鼠Treg细胞测定及分选的价值。收集BALB/c小鼠外周血及制备脾细胞悬液,分别三重荧光染色CD4、CD25、CD127及CD4、CD25、Foxp3后应用流式细胞仪检测,得出CD4+CD25+CD127low/-、CD4+CD25+Foxp3+这两种标记的小鼠外周血和脾脏Treg细胞的比例;再在CD4、CD25、Foxp3基础上加CD127染色(四重荧光染色),检测CD4+CD25+CD127low/-细胞Foxp3转录因子的表达情况。结果显示:①BALB/c小鼠外周血CD4+T细胞的分布:在总T细胞中CD4+TCD4+CD25+T细胞的中位表达水平分别为39.02%、5.35%;在CD4+T细胞中CD4+CD25+CD127low/-、CD4+CD25+Foxp3+细胞的中位表达水平分别为7.13%、3.97%;②BALB/c小鼠脾脏CD4+T细胞的分布:在总T细胞中CD4+T、CD4+CD25+T细胞的中位表达水平分别为23.49%、3.86%;在CD4+T细胞中CD4+CD25+CD127low/-、CD4+CD25+Foxp3+细胞的中位表达水平分别为12.8%、8.23%;③BALB/c小鼠外周血和脾脏CD4+CD25+CD127low/-细胞比例高于CD4+CD25+Foxp3+细胞,以脾脏更为明显(P<0.01);④小鼠外周血及脾脏CD4+CD25+CD127low/-细胞高表达Foxp3转录因子,CD4+CD25+Foxp3+细胞低表达CD127。结论:BALB/c小鼠外周血和脾脏CD4+CD25+CD127low/-较CD4+CD25+Foxp3+能定量更多的Treg细胞;CD127low/-作为CD4+CD25+Treg细胞表面的特征性标志,在细胞分选时受其他细胞的干扰最小,是定量和纯化小鼠Treg细胞的更好标记选择。     

Foxp3转染小鼠CD4^＋CD25^-T细胞抑制树突状细胞功能

为了研究Foxp3基因表达与CD4^＋T细胞免疫活性的关系,用逆转录病毒转染Foxp3基因,在幼稚CD4^＋CD25^-T细胞内强制性表达FOXP3蛋白,进而研究转染后的CD4^＋CD25^-T细胞对树突状细胞的免疫共刺激分子和免疫功能的影响,并通过Transwell试验研究转染Foxp3的CD4^＋CD25^-T细胞对树突状细胞的作用是否依赖于细胞之间的直接接触。结果表明：通过逆转录病毒载体转染,成功建立了表达Foxp3的CD4^＋CD25^-T细胞模型,转染后1周Foxp3阳性表达的T细胞比例为38%。强制性表达Foxp3的CD4^＋CD25^-T细胞可以在体外发挥免疫抑制作用,可以诱导树突状细胞表面免疫共刺激分子CD80和CD86表达水平的下调。体外淋巴细胞增殖试验结果表明,Foxp3转染小鼠CD4^＋CD25^-T细胞可以抑制树突状细胞对异基因淋巴细胞的活化。结论：转染Foxp3的CD4^＋CD25^-T细胞对树突状细胞发挥的作用依赖于细胞之间的直接接触。     

不同树突状细胞对CD4~+CD25~+Foxp3~+调节性T细胞体外扩增的影响

目的利用不同种类树突状细胞(dendritic cells,DC)体外扩增获得表型和功能稳定的CD4+CD25+Foxp3+调节性T细胞(Treg)。方法免疫磁珠法(MACS)分离Balb/c小鼠CD4+CD25+调节性T细胞,利用与调节性T细胞同基因或异基因成熟DC、未成熟DC和调节性DC刺激其扩增,流式细胞术测定其纯度和表型。以CD4+CD25-T细胞作为反应细胞,验证扩增前后Treg细胞的免疫抑制功能。结果MACS分离的CD4+CD25+调节性T细胞纯度达到(95.38±1.82)%,同基因和异基因DC都能有效刺激Treg细胞体外扩增,其中同基因成熟DC扩增效果最为明显。而且同基因成熟DC扩增后CD4+CD25+调节性T细胞纯度达到(94.16±1.88)%,而且高表达Foxp3分子。当CD4+CD25+调节性T细胞与效应T细胞比例为1∶1时,能够有效的抑制效应T细胞的增殖,而且,同基因成熟DC扩增的CD4+CD25+调节性T细胞的抑制效果比新分离的Treg效果更好。结论同基因成熟DC能够体外扩增表型和功能稳定的Treg细胞。     

人Foxp3基因真核载体的构建及在CD4+CD25-T细胞中的表达和功能

目的:构建人Foxp3基因的真核表达栽体并转染人CD4+CD2-T细胞,观察其在CD4-CD25-T细胞中的表达及功能.方法:构建人Foxp3基因pEGFP-N1真核表达栽体,经酶切及双向测序鉴定基因序列的正确性.通过电穿孔法将重组栽体转入人CD4+CD25-T细胞中,利用荧光显微镜及流式细胞术检测转染效率,采用3H-TdR掺入法检测转染细胞对单个核细胞增殖能力的影响.结果:酶切及测序鉴定pEGFP-Nl-Foxp3重组质粒基因序列完全正确,转染的CD4+CD25-T细胞Foxp3阳性表达率为23.7%,并显著抑制了单个核细胞的增殖能力.结论:成功构建了pEGFP-N1-Foxp3真核表达栽体,并使转染的CD4+CD25-T细胞具有调节性T细胞的功能.     

脐血和成人外周血中CD4+CD25+调节性T细胞的表型及频率比较

目的:比较脐血和成人外周血中CD4+CD25+调节性T细胞的表型及频率.方法:密度梯度离心法分离15例新生儿脐血和12例正常健康成人外周血.应用流式细胞术分析CD4+CD25+调节性T细胞中CD45RA、CD45RO及胞内抗原Fouxp3的表达情况:检测CD4+CD25brught/CD4+T和CD4+CD25dim/CD4+T的百分比.结果:与成人外周血相比,脐血中CD4+CD25+调节性T细胞显示为独立的细胞群;CD4+T细胞、CD4+CD25dim/CD4+T比例增高:而CD4+CD25+/CD4+T、CD4+CD25brught/CD4+T的比例降低.在表型方面,脐血CD4+CD25+调节性T细胞大部分是CD45RA+的细胞,同时表达Foxp3,但含量较成人外周血低.结论:与成人外周血相比,脐血中存在数量较多的CD4+CD25+调节性T细胞,但功能尚未成熟,可能更适合作为调节性T细胞体外培养的标本来源.     

半乳凝素-10在CD4^＋CD25^＋CD127^low／-调节性T细胞中的表达与意义

目的探讨半乳凝素-10(galectin-10)在CD4 CD25 CD127low/-调节性T细胞(regulatory T cell,Treg)中的表达及其与Foxp3的相关性。方法通过流式细胞术分选健康人外周血和胃癌患者癌旁淋巴结中Treg细胞与CD4 CD25-CD127 T细胞,经微量抽提RNA后,用RT-PCR检测galectin-10和Foxp3的mRNA表达水平。结果galectin-10和Foxp3的mRNA显著表达于Treg细胞,几乎不表达于CD4 CD25-CD127 T细胞。健康人外周血和胃癌患者癌旁淋巴结中的结果一致。结论ga-lectin-10基因高表达于Treg细胞中,可以作为Treg细胞一项新的标志物。     

紫癜性肾炎患儿外周血CD4+CD25+调节性T细胞的临床意义

目的 研究紫癜性肾炎(HSPN)患儿外周血CD4+CD25+调节性T细胞数量、相关细胞因子的水平及Foxp3的表达,探讨它们在HSPN发病机制中的作用.方法 分别采集40例HSPN患儿及20例健康儿童外周静脉血,通过流式细胞仪分析CD4+CD25+调节性T细胞百分率,ELISA测定血浆IL-10和TGF-β1水平,荧光定量PCR(Real-time PCR)检测T细胞Foxp3mRNA的表达.结果 HSPN患儿外周血CD4+T,CD25+T,CD4+CD25+T/CD4+T均低于对照组(P<0.05);T细胞Foxp3mRNA的表达明显降低,血浆IL-10水平也明显低于对照组(P<0.05),血浆TGF-β1水平较对照组明显升高(P<0.01);CD4+CD25+调节性T细胞百分率随HSPN病理分级加重有降低趋势,二者呈负相关(r＝-0.966,P<0.01).结论 HSPN患儿外周血存在细胞免疫功能失调,CD4+CD25+调节性T细胞数量减少或功能异常,导致免疫抑制效应不足,参与并促进了儿童HSPN的发生发展,其外周血水平与HSPN病理分级有相关性.     

CD137 enhances cytotoxicity of CD3CD56 cells and their capacities to induce CD4 Th1 responses

CD137 (4-1BB) is a TNFR superfamily member that mediates the costimulatory signal resulting in T cells and NK cells proliferation and cytokines production, but the effects of CD137 signaling on CD3⁺CD56⁺ cell subpopulation have not been well-documented. The aim of this study was to investigate the effects of CD137 signaling on regulation of CD3⁺CD56⁺ cell function. Anti-CD137 mAb or mouse IgG1 isotype control was added to CIK cell culture to determine the effects of proliferation and anti-tumor effects on CD3⁺CD56⁺ cells. We observed that anti-CD137 mAb could dramatically promote proliferation of CIK cells. And CD137–CIK cells and CD3⁺CD56⁺ cell subpopulation within them possessed higher ability to kill tumor cell line A549. The SCID mice engrafted with A549 cells and treated with CD137–CIK cells have prolonged survival. Further studies revealed that the percentages of CD3⁺CD56⁺ cells were elevated significantly in CD137–CIK cells. The expression of NKG2D was up-regulated on CD3⁺CD56⁺ cells from CD137–CIK cells. The expression of IFN-γ, IL-2 and TNF-α increased significantly whereas the production of TGF-β₁, IL-4 and IL-10 decreased in CD3⁺CD56⁺ cells from CD137–CIK cells. In addition, anti-CD137 mAb can elevate the capacity of CD3⁺CD56⁺ cells to induce CD4⁺ Th1 responses. We further showed that the anti-CD137 mAb also had the same effects on CD3⁺CD56⁺ cells expanded from the PBMCs of patients with NSCLC. We concluded that CD137 signaling could enhance the abilities of CIK cells to kill tumor cells in vitro and in vivo via increasing the proportion of CD3⁺CD56⁺ cells and their cytotoxicity. Furthermore, CD137 signaling can elevate the capacity of CD3⁺CD56⁺ cells to induce CD4⁺ Th1 responses which may enhance their anti-tumor activity indirectly. Taken together, our studies could be considered as valuable in CIK cells-based cancer immunotherapy.     

Tyrosine phosphorylation of CD6 by stimulation of CD3: augmentation by the CD4 and CD2 coreceptors

When T cells are activated via the T cell receptor (TCR) complex a number of cellular substrates, including some cell surface proteins, become phosphorylated on tyrosine (Tyr) residues. Phosphorylation of cytoplasmic Tyr renders these cell surface receptors competent to interact with proteins that link cell surface receptors to protein in the intracellular signaling pathways. Here we show that Tyr residues in the cytoplasmic domain of CD6 become phosphorylated upon T cell activation via the TCR complex. Tyr phosphorylation was observed when the T cells were activated by crosslinking CD3 or by cocrosslinking CD3 with CD2 or CD4, but not when the cells were stimulated by crosslinking CD2, CD4, or CD28 alone. Unlike other Tyr kinase substrates, such as the phospholipase C gamma 1-associated pp35/36 protein, whose level of Tyr phosphorylation is highest when T cells are activated by cocrosslinking CD3 with CD2, the levels of CD6 Tyr phosphorylation are highest when T cells were activated by cocrosslinking CD3 with CD4.     

Differential increase of CD34, KDR/CD34, CD133/CD34 and CD117/CD34 positive cells in peripheral blood of patients with acute myocardial infarction

Objective Circulating progenitor cells (CPC) may contribute to cardiac regeneration and neovascularization after acute myocardial infarction (AMI). For potential therapeutic use, understanding the endogenous mechanisms after ischemia is inevitable. We investigated the absolute number, but also the subset composition of CD34+ CPC after AMI. Methods CD34+, KDR+/ CD34+, CD133+/CD34+ and CD117+/CD34+ CPC were analyzed by FACS in peripheral blood of 10 patients with acute MI (59±5 yrs, m/f=8/2) at day of AMI (day 0) and days 1–5. For comparison patients with stable coronary artery disease (CAD, n=12, 66±2 yrs, m/f=10/2) and young healthy volunteers (n=7, 26±2 yrs, m/f=3/4) were studied. Results CD34 and KDR/CD34, CD133/CD34, CD117/CD34 were increased day 3 and 4 after AMI. KDR+ fraction within CD34+ population remained unchanged (58.3±7.8% vs 55.3±10.6%), whereas CD133+ (64.9±3.1% vs 43.5±5.9%, P=0.006) and CD117+ fractions (71.7±5.6% vs 50.1±5.5%, P=0.02) were elevated. In CAD, all CPC and fractions were similar as AMI day 0. Healthy volunteers had more CD34+ than CAD and AMI day 0. Double positive CPC were also higher, but fractions were unchanged vs CAD with more KDR/CD34 in trend (72.8±10.6% vs 50.5±5.6%, P=0.058). After AMI both absolute numbers of CD34+ and their subset composition change, suggesting selective mobilization of CPC. Increased CPC after AMI never reach numbers of young healthy volunteers.     

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.     

Human CD3+ T lymphocytes that express neither CD4 nor CD8 antigens

CD3+ T lymphocytes expressing neither CD4 nor CD8 antigens exist in normal human peripheral blood in low frequency (approximately 3% of lymphocytes). The CD3+,4-,8- phenotype was stably maintained after in vitro culture in IL-2. Culture of CD3+,4-,8- cells in only rIL-2 generated cytotoxic T cells that lysed NK-sensitive and NK-insensitive tumor cell targets without MHC restriction. These experiments clearly show that phenotypically and functionally competent T cells expressing neither CD4 nor CD8 are present in normal peripheral blood.     

Contribution of CD4+, CD8+CD28+, and CD8+CD28- T cells to CD3+ lymphocyte homeostasis during the natural course of HIV-1 infection.

The relationship between the number of circulating CD4+ T cells and the presence of particular CD8+ T cell subsets was analyzed by flow cytometry on PBL from asymptomatic HIV-1-infected patients whose specimens were collected every 2 mo for a total period of 32 mo. Only slight variations were detected in the absolute number of lymphocytes and percentage of CD3+ lymphocytes, whereas both CD4+ and CD8+ T cell subsets showed wide intrapatient variation. Variations in the number of CD8+CD28+ cells paralleled those of the CD4+ T cell subset in each patient tested, while the presence of CD8+CD28- T cells correlated inversely with CD4+ and CD8+CD28+ T cells. These data show that changes in the number of circulating CD4+-and CD8+CD28+ T cells are strongly related to the presence of CD8+CD28- T cells in these patients. Insight into the significance of CD8+CD28- T cell expansion will allow us to understand the mechanisms and significance of the HIV-1- driven change in CD4+CD8+ T cell homeostasis and the basic immunopathology of HIV disease.     

CD8alpha- CD11b+ dendritic cells present exogenous virus-like particles to CD8+ T cells and subsequently express CD8alpha and CD205 molecules

Recombinant porcine parvovirus virus-like particles (PPV-VLPs) are particulate exogenous antigens that induce a strong, specific cytotoxic T lymphocyte (CTL) response in the absence of adjuvant. In the present report, we demonstrate in vivo that dendritic cells (DCs) present PPV-VLPs to CD8+ T cells after intracellular processing. PPV-VLPs are captured by DCs with a high efficacy, which results in the delivery of these exogenous antigens to 50% of the whole spleen DC population. In vivo, a few hours after injection, PPV-VLPs are presented exclusively to CD8+ T cells by CD8alpha- DCs, whereas 15 hours later they are presented mainly by CD8alpha+ DCs. After PPV-VLPs processing, a fraction of CD11b+ DCs undergo phenotypic changes, i.e., the up-regulation of CD8alpha and CD205 and the loss of CD4 molecules on their surface. The failure to detect mRNA coding for CD8alpha in CD11b+ DCs suggests that CD8alpha expression by these cells is not due to de novo synthesis. In recombination-activating gene knockout mice (Rag-/-), CD11b+ DCs did not express CD8alpha and PPV-VLPs presentation by CD8alpha+ DCs was severely diminished. These results indicate that both CD8alpha- and CD8alpha+ DCs play an important role in the induction of CTL responses by exogenous antigens, such as VLP.