体外扩增自体CD4~+CD25~+调节性T细胞促进小鼠供体来源肿瘤的转移

目的研究输注体外扩增自体CD4+CD25+调节性T细胞(regulatory T cells,Tregs)治疗是否存在增加供体来源肿瘤转移的风险。方法取Balb/c(H-2d)小鼠骨髓细胞,在重组鼠源性GM-CSF和IL-4诱导以及TNF-α刺激下分化为成熟树突状细胞。免疫磁珠法(MACS)从Balb/c(H-2d)小鼠脾脏分选出CD4+CD25+Tregs,加入成熟树突状细胞和高浓度重组鼠源性IL-2,体外扩增7 d。流式细胞术检测新鲜以及扩增后CD4+CD25+Tregs纯度及免疫抑制功能。将Balb/c(H-2d)小鼠随机分为2组,实验组:经尾静脉注射1×107体外扩增后CD4+CD25+Tregs,24 h后注射5×105 B16-F10(H-2b)(鼠源性黑色素瘤细胞);对照组:单独输注5×105 B16-F10(H-2b)。结果新鲜分选和扩增后CD4+CD25+Tregs纯度及免疫抑制功能无明显下降。对照组肺部肿瘤结节为(9±8)个,实验组肺部肿瘤结节为(118±15)个。与对照组相比,实验组肺部肿瘤结节明显增加(P0.01)。结论体外扩增的CD4+CD25+Tregs具有抑制机体抗肿瘤能力,过继输注体外扩增的自体CD4+CD25+Tregs治疗移植后排斥反应,能够增加供体来源肿瘤转移的风险。     

小鼠CD4~+ CD25~+ Foxp3~+调节性T细胞体外扩增

目的:本研究旨在探讨CD4+CD25+Foxp3+调节性T细胞体外扩增的方法。方法:采用磁珠分选小鼠CD4+T细胞,αCD3单克隆抗体包被24孔板,加入αCD28单克隆抗体、雷帕霉素、rhIL-2,培养3周后,流式细胞仪测定培养细胞中CD4+CD25+T细胞的含量,实时定量PCR检测CD4+CD25+T细胞Foxp3 mRNA的表达;单向混合淋巴细胞反应和增殖抑制试验测定扩增的CD4+CD25+T细胞的增殖及其抑制功能;ELISA检测培养上清中IL-10和TGF-β1的含量。结果:小鼠CD4+T细胞培养3周后,CD4+CD25+T细胞达(76.05±2.73)%,高于未加雷帕霉素组(52.17±1.36)%(P<0.001),磁珠分选的CD4+CD25+T细胞Foxp3 mRNA的表达是未加雷帕霉素组的5倍(P<0.001),增殖能力是未加雷帕霉素组的0.29倍(P<0.001),对CD4+T细胞增殖抑制能力是未加雷帕霉素组的3.6倍(P<0.001),培养上清中IL-10和TGF-β1分别是对照组的1.8倍和1.6倍(P<0.001)。结论:小鼠CD4+T细胞在含有1μg/ml的αCD28、rhIL-2 100 U/ml和终浓度为10 nmol/L雷帕霉素的培养体系中培养3周后能有效扩增CD4+CD25+Foxp3+调节性T细胞。     

IL-2抑制小鼠CD4~+ CD62L~+ T细胞分化为Th17细胞

目的研究IL-2对小鼠脾脏CD4+CD62L+T细胞在体外向Th17细胞分化的作用。方法免疫磁珠法分选C57BL/6小鼠脾脏CD4+CD62L+T细胞,于抗体包被的培养板中培养3 d,实验分为对照组和IL-2处理组。对照组为经典Th17诱导分化培养基,IL-2处理组在对照组基础上于培养体系中添加IL-2。CFSE染色检测细胞增殖,Annexin V-PI法检测细胞凋亡,ELISA检测培养上清中IL-17A的浓度,荧光定量PCR检测Rorγt mRNA的表达,流式细胞术检测CD4~+IL-17~+Th17的生成比例以及Rorγt的表达。结果磁珠分选的小鼠脾脏CD4+CD62L+nave T细胞纯度高于95%。与对照组相比,IL-2处理组细胞数目明显增多,增殖能力明显增强(P0.05),细胞凋亡比例降低(P0.05);IL-2处理组培养上清中IL-17A的浓度明显降低(P0.05),且CD4+IL-17+细胞比例下降,其特异性转录因子Rorγt的表达水平也显著降低(P0.05)。结论 IL-2在CD4+CD62L+T细胞分化为Th17的过程中,能够促进T细胞的增殖并且抑制Th17的分化。     

糖原合酶激酶-3β抑制剂TWS119联合细胞因子促进CD45RA~+CD62L~+γδT细胞分化及功能

目的体外研究糖原合酶激酶-3β抑制剂TWS119联合细胞因子IL-7、IL-15和IL-21对CD45RA~+CD62L~+γδT细胞分化、凋亡及其功能的影响。方法采用帕米磷酸二钠和IL-2体外扩增健康人外周血单个核细胞中的γδT细胞或联合加入IL-7、IL-15、IL-21和TWS119进行诱导培养。采用细胞计数仪和流式细胞仪检测各培养组中γδT细胞的增殖、分化、凋亡、细胞因子分泌及其杀伤肿瘤活性。结果 IL-7、IL-15和IL-21联合TWS119可以促进γδT细胞分化、增殖和抗凋亡能力,尤其在TWS119+IL-7/15/21联合组中,CD45RA~+CD62L~+γδT细胞的比例与数量最高,且该群细胞在体外具有持续的增殖、IFN-γ分泌和杀伤人肝癌HepG2细胞活性。结论在帕米磷酸二钠和IL-2的培养条件下,TWS119体外联合细胞因子IL-7、IL-15和IL-21可以有效扩增CD45RA~+CD62L~+γδT细胞,为后期该群细胞体内抗肿瘤活性研究和临床应用提供依据。     

CD4~+CD25~+调节T细胞对内皮细胞炎性因子分泌的影响

目的:探讨CD4+CD25+调节性T细胞(Tregs)对氧化型低密度脂蛋白(ox-LDL)诱导人脐静脉内皮细胞(HU-VECs)VCAM-1、MCP-1、IL-6表达的影响。方法:磁性细胞分离器(MACS)分离CD4+CD25+T细胞及CD4+CD25-T细胞。在ox-LDL作用下,将内皮细胞分别与anti-CD3mAb激活的CD4+CD25+T细胞,CD4+CD25-T细胞共培养24小时。分别应用流式细胞术、ELISA、real-timePCR测定Tregs对ox-LDL诱导损伤HUVECs炎性因子VCAM-1、MCP-1、IL-6表达的影响。应用Transwell小室及中和抗体实验观察Tregs作用于HUVECs的具体机制。结果:与对照组比较,Tregs细胞可显著抑制ox-LDL诱导损伤HU-VECs炎性因子VCAM-1、MCP-1、IL-6的表达;被Transwell隔离或加入中和性抗体anti-IL-10/anti-TGF-β后,Tregs对HUVECs的抑制作用可被部分逆转。结论:Tregs细胞可显著抑制ox-LDL诱导损伤HUVECs炎性因子的表达,其作用机制既依赖于细胞直接接触,又依赖于细胞因子。     

CD4~+CD25~+调节性T细胞在自身免疫性甲状腺疾病中数量和功能变化

目的:探讨自身免疫性甲状腺疾病患者外周血中CD4+CD25+调节性T细胞(Tregs)的数量和功能变化。方法:采用化学发光法测定20例初发Graves’病人、20例初发桥本甲状腺炎(HT)患者及20例健康体检者血清中促甲状腺素(TSH)、总三碘甲状腺原氨酸(TT3)、总甲状腺素(TT4)、甲状腺球蛋白抗体(TgAb)和甲状腺过氧化酶抗体(TPOAb)的水平;用流式细胞仪分析外周血单个核细胞(PBMC)中CD4+T细胞及CD4+CD25+Tregs的数量;采用磁珠分选技术分选5例HT病人和5例健康体检者PBMC中CD4+CD25+Tregs和CD4+CD25-T细胞,采用MTT法检测CD4+CD25+Tregs对自身CD4+CD25-T细胞增殖的抑制作用;提取各组PBMC的总RNA,经Real time-PCR检测TGFβ-1、Foxp3 mRNA的表达水平。结果:流式细胞检测结果显示,初发Graves’病人、初发HT患者外周血PBMC中CD4+T细胞数量与正常人比较无差异(P<0.05);初发HT患者外周血PBMC中CD4+CD25+Tregs占CD4+T细胞的比率为(1.55%±0.49%),明显低于正常对照组(2.86%±1.04%)(P<0.05);初发Graves’病人外周血PBMC中CD4+CD25+Tregs占CD4+T细胞的比率为(3.25%±0.97%),与正常对照组(2.86%±1.04%)相比无显著性差异(P<0.05)。MTT结果显示,初发HT患者CD4+CD25+Tregs对自身CD4+CD25-T细胞增殖的抑制百分率为15.7%±5.36%,与正常组(41.7%±9.87%)相比显著降低(P<0.05)。Real time-PCR结果显示,初发Graves’病人、初发HT患者PBMC的TGFβ-1 mRNA表达水平分别为(0.37±0.10)和(0.43±0.09),均明显低于正常对照组(1.02±0.04)(P<0.05);初发Graves’病人、初发HT患者PBMC的Foxp3 mRNA表达水平分别为0.62±0.09和0.42±0.29,均明显低于正常对照组(0.99±0.17)(P<0.05)。结论:本研究结果提示,HT患者外周血中CD4+CD25+Tregs的数量和功能明显降低。Graves’病和HT患者外周血PBMC中TGFβ-1、Foxp3 mRNA表达水平明显降低。     

脂多糖通过调控树突状细胞存活和分泌细胞因子促进CD4~+T细胞增殖

目的探索脂多糖(LPS)调节树突状细胞(DC)的功能,促进T细胞免疫反应的机制。方法应用CDllc~+免疫磁珠分离小鼠脾脏DC。LPS处理DC后。流式细胞术检测DC表面的共刺激分子CD80和CD86的表达,ELISA检测DC培养上清中白细胞介素4(IL-4)、IL-5、IL-6、IL-12p40、IL-12p70、肿瘤坏死因子α(TNF-α)的水平,异硫氰酸荧光素标记的膜联素Ⅴ/碘化丙啶(annexinⅤ-FITC/PI)双染色结合流式细胞术检测DC凋亡,Phos-flow技术检测核因子κB P65(NF-κB P65)磷酸化水平,实时定量PCR检测基因芯片变化差异明显基因的mRNA水平,DC经OVA323-329多肽处理后与和CD4~+T细胞共培养,流式细胞术检测CD4~+T细胞的增殖。结果利用CD11 c磁珠分离,可获得纯度为93%的DC,LPS可以上调DC表面CD80和CD86的表达,增强DC介导的CD4~+T细胞的增殖。并且LPS能促进促炎细胞因子IL-12 p40、TNF-α和IL-6的分泌,同时通过NF-κB通路抑制DC的凋亡。结论 LPS通过调节DC的存活和细胞因子的产生促进DC介导的CD4~+T细胞的增殖。     

人源化NOD小鼠中CD8~+CD25~+Tregs的频率和功能研究

目的观察分析人源化NOD小鼠体内CD8+CD25+T细胞的频率及功能,探讨CD8+CD25+T细胞在人源化NOD小鼠的自身免疫进程中的作用。方法采用流式细胞术检测人源化NOD小鼠脾、胰腺引流淋巴结、腹股沟淋巴结中CD8+CD25+T、CD8+CD25+Foxp3+T细胞的频率及脾CD8+CD25+T细胞的表型和细胞因子分泌谱,并采用3H-Td R掺入法检测脾CD8+CD25+T细胞的免疫抑制功能。结果人源化NOD小鼠胰腺引流淋巴结中CD8+CD25+T和CD8+CD25+Foxp3+T细胞频率显著高于脾和腹股沟淋巴结中这2亚群的频率;与CD8+CD25-T细胞相比,脾CD8+CD25+T细胞高表达Foxp3、CTLA-4、CD103、CD62L,同时低分泌细胞因子IFN-γ及高分泌IL-17A;人源化NOD小鼠脾CD8+CD25+T细胞能有效地抑制效应性CD4+CD25-T细胞的增殖。结论人源化NOD小鼠的CD8+CD25+T细胞是一群具有免疫抑制功能的Tregs,并且高表达Tregs的表型和细胞因子谱,提示CD8+CD25+Tregs可能在外周和胰腺局部参与了人源化NOD小鼠T1D的免疫耐受进程。     

胃癌患者不同区域淋巴结和外周血CD4~+CD25~+Foxp3~+调节性T细胞的表达和临床意义

目的探讨胃癌患者不同区域淋巴结及外周血中CD4+CD25+Foxp3+调节性T细胞(Tregs)频数变化和临床意义。方法收集45例胃癌患者不同区域淋巴结及外周血标本,采用流式细胞仪检测各标本中Tregs占CD4+T细胞比例,并与胃癌TNM分期、分化程度等参数进行相关性分析。结果 Tregs在引流区阳性淋巴结、引流区阴性淋巴结、非引流区淋巴结、外周血中比例分别为(20.71±2.72)%、(14.43±2.62)%、(10.09±2.27)%、(9.72±2.13)%,前3组中两两相比均差异显著(P0.05),后2组相比无显著差异(P0.05)。引流区阳性淋巴结中Tregs细胞比例与肿瘤分期无显著相关(P0.05);引流区阴性淋巴结、非引流区淋巴结、外周血中Tregs细胞比例与肿瘤分期相关(r=0.429、0.453、0.367;P0.05),且Ⅲ+Ⅳ期Tregs比例显著高于Ⅰ+Ⅱ期比例。不同区域淋巴结Tregs分布与年龄、性别、肿瘤部位、病理分化间差异无相关性。结论 Tregs在不同区域淋巴结及外周血中分布表达呈递减趋势,可能是导致胃癌淋巴结微环境内出现局部免疫抑制,导致肿瘤细胞发生免疫逃逸的重要因素。     

肺炎链球菌肺炎对肺部树突状细胞及CD4~+T细胞的影响

目的探讨肺炎链球菌肺炎对Balb/c小鼠肺部树突状细胞及CD4~+T细胞的影响。方法 6~8周Balb/c小鼠随机分为对照组及肺炎链球菌感染组,流式细胞术检测肺炎链球菌感染后2 d、5 d肺组织中CD103~+DCs、CD11b~+DCs、p DCs及CD4~+T细胞亚类水平。结果肺炎链球菌肺炎致肺组织CD103~+DCs及p DCs水平显著增高,与对照组比较差异有统计学意义(P0.01),而肺组织CD11b~+DCs水平显著低于对照组。肺炎链球菌肺炎促进肺组织IL-17A~+CD4~+T细胞和Foxp3~+Tregs表达,与对照组比较,感染后2 d、5 d差异均有统计学意义(P0.05),随着感染控制,Foxp3~+Tregs表达水平回降,感染后5 d Foxp3~+Tregs水平显著低于感染后2 d水平(7.3%±0.41%vs 9.38%±1.34%,P0.01)。肺炎链球菌肺炎对肺部Th2表达水平无显著影响,感染后5 d IFN-γ~+CD4~+T细胞水平显著升高,与对照组、感染后2 d组比较,差异有统计学意义(P0.01)。结论肺炎链球菌肺炎促进肺组织CD103~+DCs、p DCs表达,诱导CD4~+Th17、Tregs细胞分化发育。     

雷帕霉素对人CD4~+CD25~+调节性T细胞体外扩增的影响

探讨有效的体外扩增人CD4~+CD25~+调节性T细胞(Treg)的方法以及雷帕霉素(rapamycin,RAPA)对人CD4~+CD25~+Treg细胞体外扩增的影响。采用免疫磁珠分离人外周血的CD4~+CD25~+Treg,并将实验分为3组:第1组在CD4~+CD25~+Treg培养体系中加入200 U/ml IL-2和包被CD3/CD28单克隆抗体的磁珠;第2组培养体系中除加入100 nmol/LRAPA以外,其余与第1组相同;第3组是CD4~+CD25~+Treg培养第12天后,将细胞进一步分选获取CD4~+CD25~+CD127~- Treg再继续培养,培养体系与第2组相同。实验结果显示,加RAPA培养的CD4~+CD25~+Treg细胞扩增效率比不加RAPA的低,但细胞的纯度明显提高(92%vs 65%)。而加RAPA培养的第2、3组CD4~+CD25~+Treg细胞在纯度上没有明显的差异。加RAPA培养的CD4~+CD25~+Treg细胞扩增后保持其无能状态。体外抑制实验显示体外扩增的CD4~+CD25~+Treg细胞对CD4~+效应T细胞增殖均有明显的抑制作用,而且加RAPA扩增的Treg细胞表现出更强的抑制功能。另外,与第1组体外扩增的Treg细胞相比,加RAPA扩增的Treg细胞表达低水平的IL-2和IFN-γ。实验证明雷帕霉素抑制了CD4~+ CD25~+Treg细胞中混杂的CD4~+效应T细胞的扩增,使用雷帕霉素可以提高体外扩增CD4~+CD25~+Treg细胞的纯度及其免疫抑制功能。     

B7H1-Ig诱导Tr1细胞向CD4~+CD25~+Foxp3~+Treg细胞转化的研究

为探讨Ⅰ型调节性T细胞(Tr1)与CD4+CD25+Foxp3+Treg之间的转化和相互关系,以预包被而固相化的B7H1-Ig融合蛋白加抗CD3单抗刺激初始CD4+CD62L+T细胞,分析细胞因子及Foxp3表达水平的变化,检测细胞功能;在B7H1-Ig开始刺激时或诱导细胞分化结束后加入重组人TGF-β,观察其对细胞分化的影响。结果显示,B7H1-Ig激活的CD4+T细胞产生高水平IL-10、IFN-γ和IL-5,极低水平的IL-2和IL-4,不表达Foxp3,通过分泌抑制性细胞因子IL-10发挥免疫抑制功能,证实B7H1-Ig可诱导Tr1细胞的产生。同时发现TGF-β不影响B7H1-Ig刺激的初始CD4+T的分化,却可促进B7H1-Ig诱导的已分化Tr1细胞向CD4+CD25+Foxp3+Treg转化,提示在特定条件下,Tr1细胞可转化的CD4+CD25+Foxp3+Treg。研究结果为将来临床应用CD4+Treg治疗免疫失调性疾病奠定了基础。     

CD4~+CD25~+Foxp3~+调节性T细胞与LSCC发病的相关研究

为研究调节性T细胞在喉鳞状细胞癌(laryngeal squamous cell carcinoma,LSCC)、发展中的变化及其参与疾病进展的作用机制,收集2010～2011年上海市五官科医院收治的50例LSCC患者的肿瘤组织和外周血,应用流式细胞术检测CD4+CD25+Foxp3+Treg细胞及趋化因子受体CCR6的表达变化,Real-time PCR法检测转录因子Foxp3以及细胞因子mRNA的表达量。结果发现:LSCC患者外周血中CD4+CD25+Foxp3+Treg的百分比较正常人显著增加,并与临床分期相关;CD4+CD25+CCR6+Treg Foxp3的表达,以及肿瘤组织Foxp3mRNA的表达皆明显高于对照组,且与临床分期、淋巴结转移相关。同时发现,LSCC患者外周血中TGF-β和IL-10mRNA的检出水平分别高于对照组,但IFN-γ、IL-2、IL-12mRNA的水平低于对照组。提示此类Foxp3+Treg属于一类诱导性T抑制细胞(Foxp3+iTreg),可通过产生IL-10和TGF-β抑制LSCC患者的细胞免疫功能。Foxp3的检测可能对判断LSCC的预后有一定价值。     

Effects of interleukin 4 on CD25+CD4+ regulatory T cell function

CD25+CD4+ regulatory T cells (Tregs) contribute to the maintenance of peripheral tolerance against self and non-self. The modulatory effects of cytokines, such as interleukin 4 (IL-4) on the function of Tregs have not been explored in detail. We here report that IL-4 prevents spontaneous apoptosis and the decline of foxp3 mRNA which were found to occur during culture of isolated Tregs. Tregs exposed to IL-4 were more potent in suppressing the proliferation of na?ve CD4+ T cells and they better inhibited IFN-gamma production by CD4+ T cells as compared to Tregs cultured in medium. IL-4 also enhanced membrane IL-2Ralpha (CD25) expression on Tregs above the levels observed on freshly isolated cells. IL-4-mediated effects on Treg function persisted in Tregs from Stat6-/- mice, pointing to a Stat6-independent intracellular transduction pathway. In conclusion, our data suggest that the anti-inflammatory function of IL-4 could partly be mediated by effects on Tregs function.     

IL-21 modulates CD4+ CD25+ regulatory T-cell homeostasis in experimental autoimmune encephalomyelitis

Abstract The homeostasis of CD4 ⁺ CD25 ⁺  regulatory T cells (Tregs) depends on the cytokine interleukin (IL)-2. As IL-21 shares sequence homology with IL-2 and the IL-21 receptors contain a γ-chain common to IL-2, we hypothesized that IL-21 could also affect the homeostasis of Tregs. We tested this hypothesis in experimental autoimmune encephalomyelitis (EAE), an animal model of relapsing-remitting human multiple sclerosis. We show that blockade of IL-21 in SJL/J mice before and after the induction of EAE enhances the influx of inflammatory cells into the central nervous system (CNS). The blockade of IL-21 leads to proliferation of proteolipid peptide (PLP_139-151)-autoreactive CD4 ⁺  T cells, which are capable to cause severe EAE in adoptively transferred recipient mice. Conversely, Tregs from mice where IL-21 was blocked, lose their capacity to prevent EAE induced PLP_139-151-reactive T cells. Notably, direct effects of IL-21 on Tregs are confirmed by studies of blockade of IL-21 in mice expressing a green fluorescent protein 'knocked' into a Foxp3 allele, in which a reduction of the number of Tregs and a downregulation of their frequency and expression of Foxp3 are observed. These data suggest a role of the IL-21/IL-21R axis in the homeostasis of Tregs in CNS autoimmunity.     

多发性骨髓瘤患者外周血CD4~+CD25~+和CD8~+CD28~-调节性T细胞研究

目的:探讨CD4~+CD25~+和CD8~+CD28~-调节性T细胞(Tregs)在多发性骨髓瘤(MM)患者外周血中的变化及意义.方法:采用流式细胞术检测38例MM患者及20例健康对照外周血CD4~+CD25~+和CD8~+CD28~-Tregs水平.分别采用溴甲酚绿法、透射免疫比浊法测定患者血清白蛋白(Alb)、β2-微球蛋白(β2-MG).结果:初诊MM患者外周血CD4~+CD25~(+/high)、CD4~+CD25~(high)CD127~(low)及CD8~+CD28~-Tregs比率均明显升高;CD4~+CD25~(+/high)和CD4~+CD25~)(high)CD127~(low)Tregs比率在各临床分期均较对照组升高,随分期增高呈现增加趋势,且CD4~+CD25~(high)和CD4~+CD25~(high)CD127~(low)Tregs在Ⅲ期患者显著高于Ⅰ期患者;CD8~+CD28~(-Tregs)在Ⅱ、Ⅲ期显著高于正常对照,且Ⅱ期高于Ⅰ期,Ⅲ期高于Ⅱ期,逐期递增,而在Ⅰ期与对照组比较无显著差异;CD4~+CD25~(+/high)和CD4~+CD25~(high)CD127~(low)Tregs比率在进展期和稳定期均较对照组升高,但两期之间比较无明显差异,而CD8~+CD28~-Tregs在进展期高于稳定期及对照组,稳定期和对照组间比较无明显差异;CD4~+CD25~(high)Tregs和CD4~+CD25~(high)CD127~(low)Tregs比率与Alb水平均呈负相关.结论:MM患者体内存在CD4~+CD25~+Tregs和CD8~+ CD28~-Tregs异常增加,可能是MM免疫逃逸的一个重要机制,这些变化同临床分期、病情进展及预后存在一定程度相关性.     

IL-15 and dendritic cells induce proliferation of CD4+CD25+ regulatory T cells from peripheral blood

CD4(+)CD25(+) regulatory T cells (Tregs) have recently been the subject of intense research due to their strong immunosuppressive effect. Increasing evidence suggests that IL-15 plays an important role in Tregs biology. Nevertheless, the mechanism by which IL-15 performs this function remains to be fully elucidated. To address this question, we isolated Tregs from human peripheral blood, and utilized IL-15, dendritic cells (DCs), or DCs combined with IL-15, to examine the proliferation of Tregs and to explore related molecular mechanisms. Here, we show that IL-15 can induce the proliferation of Tregs in the presence of DCs. The induction is mediated by DCs presenting IL-15 in trans to Tregs. Simultaneously, DCs-derived IL-2, regulated by IL-15, may also play a supportive role. After IL-15 withdrawal, IL-15 trans-endosomal recycling in DCs contributes to the proliferation of Tregs. The activation of Akt, Erk1/2 and STAT(5), and the degradation of p27(kip1) may be involved in this process. These findings might explain the proliferation of Tregs in the absence of IL-2 in vivo and provide a novel method to achieve large-scale proliferation of Tregs in vitro in order to obtain cell numbers sufficient for immunotherapy.     

Expansion of regulatory T cells from umbilical cord blood and adult peripheral blood CD4+CD25+ T cells

CD4⁺CD25⁺ regulatory T cells (Treg), if properly expanded from umbilical cord blood (UCB), may provide a promising immunotherapeutic tool. Our previous data demonstrated that UCB CD4⁺CD25⁺ T cells with 4-day stimulation have comparable phenotypes and suppressive function to that of adult peripheral blood (APB) CD4⁺CD25⁺ T cells. We further examined whether 2-week culture would achieve higher expansion levels of Tregs. UCB CD4⁺CD25⁺ T cells and their APB counterparts were stimulated with anti-CD3/anti-CD28 in the presence of IL-2 or IL-15 for 2 weeks. The cell proliferation and forkhead box P3 (FoxP3) expression were examined. The function of the expanded cells was then investigated by suppressive assay. IL-21 was applied to study whether it counteracts the function of UCB and APB CD4⁺CD25⁺ T cells. The results indicate that UCB CD4⁺CD25⁺ T cells expanded much better than their APB counterparts. IL-2 was superior to expand UCB and APB Tregs for 2 weeks than IL-15. FoxP3 expression which peaked on Day 10–14 was comparable. Most importantly, expanded UCB Tregs showed greater suppressive function in allogeneic mixed lymphocyte reaction. The addition of IL-21, however, counteracted the suppressive function of expanded UCB and APB Tregs. The results support using UCB as a source of Treg cells.