细胞因子短期扩增对造血干/祖细胞黏附和迁移能力的影响

目的：探讨干细胞因子（SCF）+白细胞介素-6（IL-6）短期扩增对CD34+造血干/祖细胞黏附和迁移能力的影响。方法:用密度剃度离心的方法分离脐血CD34+细胞，经SCF和IL-6孵育48 h，用CCK-8方法检测CD34+细胞增殖能力；用流式细胞仪检测处理前后的CD49d（VLA-4）、CD11a（LFA-1）、CD62L（L-selectin）及CD184（CXCR4）的表达。用纤连蛋白（FN）包被96孔板，检测经或未经因子扩增的CD34+细胞的黏附能力。扩增的CD34+细胞悬浮于transwell培养板的上层，下层添加基质细胞衍生因子（SDF-1），流式细胞仪检测迁移细胞数，计算迁移率。结果:经SCF+IL-6处理48h后CD34+细胞扩增近3倍；表达CD49d、CD11a、CD62L及CD184的CD34+细胞的百分数分别由原来的26.34%±5.37%、17.63%±4.57%、46.38%±6.61%和9.58%±1.56%增加到65.67%±8.72%、56.67%±6.34%、84.76%±9.57%和19.32%±3.64%（P<0.01）。扩增后的CD34+细胞对FN的黏附能力及在SDF-1诱导下的迁移作用都显著增强（P<0.01）。结论:SCF+IL-6短期扩增CD34+ 造血干/祖细胞显著增加细胞的黏附能力，增加SDF-1诱导的迁移作用，可能是SCF+IL-6促进归巢的主要机制之一。     

慢性乙型病毒性肝炎患者外周血T淋巴细胞CD27和CD45RA表达的研究

目的分析慢性乙型病毒性肝炎患者外周血T淋巴细胞CD27和CD45RA的表达。方法采集分离健康人和慢性乙型病毒性肝炎患者外周血单个核细胞(PBMC),利用多种荧光标记抗体标记细胞表面分子,再用流式细胞仪检测CD8+T淋巴细胞表面CD27和CD45RA表达情况。结果31例慢性乙型病毒性肝炎患者CD8+CD45RA+CD27+T细胞占CD8+T细胞(29.03±13.18)%,低于28例健康对照组的(60.85±14.36)%,P<0.01。而CD8+CD45RA-CD27+T细胞占CD8+T细胞(30.31±24.11)%,显著高于健康对照组的(10.32±5.24)%,P<0.05。慢性乙型病毒性肝炎患者CD4+CD45RA+CD27+T细胞21.12±9.64%低于健康对照组的(60.89±17.93)%,P<0.01,而CD4+CD45RA-CD27+T细胞(54.28±18.75)%显著高于健康对照组的(27.16±9.24)%,P<0.01。结论健康人外周血CD8+和CD4+T淋巴细胞均以CD45RA+CD27+初始细胞表型为主,而慢性乙型病毒性肝炎患者外周血初始细胞减少,CD45RA-CD27+表型的T淋巴细胞明显增加。     

银杏叶提取物对肝星状细胞增殖及转化生长因子和结缔组织生长因子基因表达的影响

目的: 研究银杏叶提取物对肝星状细胞增殖及细胞因子TGF-β1、CTGFmRNA及蛋白表达的影响，以探讨银杏叶提取物抗肝纤维化的可能机制。方法: 用不同浓度(0、1、10、100、500 mg/L)的银杏叶提取物处理HSC-T6，用MTT及流式细胞仪检测其对肝星状细胞增殖及细胞周期的影响，用RT-PCR及Western blotting检测培养24 h及48 h后各组细胞中TGF-β1、CTGFmRNA及蛋白的表达。结果： 银杏叶提取物10、100、500 mg/L可抑制肝星状细胞的增殖，与空白对照组相比，G0/G1期DNA含量逐渐增加（P<0.05或P<0.01），S期DNA含量则逐渐降低（P<0.01），增殖指数(PI)逐渐降低(P<0.05 或P<0.01)；24 h各组TGF-β1mRNA及蛋白表达较对照组分别低（28±4）%、（39±4）%、（45±3）% (P<0.01)；（27±4）%、（37±4）%、（41±3）% (P<0.01)；48 h组各组TGF-β1mRNA及蛋白表达较对照组分别低（35±4）%、（49±3）%、（54±3）% (P<0.01)；(33±4)%、(48±3)%、(52±3)% (P<0.01)；4 h各组CTGF mRNA及蛋白表达较对照组分别低（29±6）%、（45±4）%、（56±3）% (P<0.01)；（36±4）%、（48±4）%、（49±3）% (P<0.01)；48 h组各组CTGF mRNA及蛋白表达较对照组分别低（48±6）%、（57±4）%、（69±3）% (P<0.01)；(44±6)%、(58±4)%、(62±3)% (P<0.01)。结论: 银杏叶提取物可能通过抑制肝星状细胞的增殖，抑制细胞因子TGF-β1、CTGF基因的表达发挥其抗肝纤维化的作用。     

香烟提取物对支气管哮喘大鼠气道平滑肌细胞增殖的影响

目的： 探讨香烟提取物（CSE）对支气管哮喘(简称哮喘)大鼠气道平滑肌细胞（ASMCs）增殖作用及可能机制。方法: 16只SD大鼠随机分为对照组和哮喘组,各8只。原代培养大鼠ASMCs,取第3-6代细胞,分为对照组、对照+CSE组、哮喘组、哮喘+CSE组、哮喘+CSE+嘧啶基-苯磺酰胺（GW8510,细胞周期蛋白依赖激酶-4抑制剂）组、哮喘+GW8510组。用流式细胞术、四甲基偶氮唑盐（MTT）法及增殖细胞核抗原（PCNA）免疫细胞化学技术检测ASMCs增殖;用逆转录-聚合酶链反应（RT-PCR）和蛋白质印迹（Western blotting）检测细胞周期蛋白D1(cyclin D1)的表达。结果: （1）哮喘组ASMCs与对照组ASMCs相比,在S+G2/M期比例、吸光度（A）值和PCNA表达率上明显增高,差异显著（P＜0.01）。（2）哮喘组ASMCs S+G2/M期比例、吸光度（A）值和PCNA表达率分别为(18.30±1.12)%、0.512±0.110、(55.1±3.7)%;哮喘+CSE组分别为（32.12±1.17）%、0.801±0.210、（90.2±7.3）%;哮喘+CSE+GW8510组分别为(17.21±0.95)%、0.508±0.009、(54.3±4.8)%;哮喘+GW8510组分别为(11.16±1.48)%、0.345±0.078、(40.6±5.4)%。除哮喘组、哮喘+CSE+GW8510组两组比较差异无显著外,其余两两比较差异均显著（P＜0.01）。（3）哮喘组、哮喘+CSE组、哮喘+CSE+GW8510组、哮喘+GW8510组ASMCs cyclin D1 mRNA A值比值和蛋白表达A值比值分别为0.236±0.045、0.271±0.002;0.369±0.124、0.379±0.002;0.231±0.075、0.261±0.002;0.165±0.064、0.193±0.002。除哮喘组、哮喘+CSE+GW8510组两组比较差异无显著外,其余两两比较差异均显著（P＜0.01）。结论: 正常与哮喘大鼠ASMCs在CSE干预后增殖明显加快,cyclin D1表达明显增加。CSE可能是通过cyclin D1参与调控哮喘大鼠ASMCs的增殖。     

CD34免疫亲合柱在脐血造血干/祖细胞分离与扩增中的应用

目的 :观察CD34免疫亲合柱对脐血造血干 祖细胞分离纯化的效果及纯化后CD34 细胞的增殖分化特性。方法 :采用CD34免疫亲合柱分离脐血单个核细胞 (MNC)中的CD34 细胞 ,流式细胞技术 (FACS)进行细胞表面标志测定。将分离前后的细胞加入造血生长因子进行液态扩增培养和多向祖细胞集落 (CFU GEMM)培养。结果 :经CD34免疫亲合柱分离后脐血中CD34 细胞为 49 6 2 %± 17 6 9% ,明显高于脐血MNC(1 17%± 0 6 8% ) ,细胞回收率为 5 4 38%± 11 91%。分离后CD34 细胞和脐血MNC经造血生长因子刺激培养 2 0d分别扩增 5 6 1 0 0倍和 44 44倍。培养至 12d时 ,免疫亲合柱分离组CD34 细胞阳性率为 5 3 38% ,对照组为 7 91%。分离组CFU GEMM产率明显高于对照组 (P <0 0 0 1)。结论 :CD34免疫亲合柱应用于脐血造血干 祖细胞的分离可充分富集CD34 细胞 ,且分离后的CD34 细胞具有明显的增殖效应和CFU GEMM形成能力。     

骨髓间充质干细胞对骨髓CD34~+细胞增殖影响的体外研究

研究骨髓间充质干细胞(bone marrow mesenchymal stem cell,BMMSC)对骨髓CD34+细胞增殖的影响,为骨髓CD34+细胞体外扩增的深入研究提供依据。用MACS进行骨髓CD34+细胞的分选;用流式细胞术进行CD34+细胞纯度鉴定;用密度梯度离心法分离引产胎儿骨髓单个核细胞,结合贴壁法进行BMMSC的体外扩增培养;用流式细胞术进行BMMSC表面标志鉴定;用Transwell培养板培养CD34+细胞与BMMSC;用自动细胞计数仪计数有活性的CD34+细胞数量;用MTT比色法检测骨髓CD34+细胞增殖活性。流式细胞术检测结果显示分选所得的CD34+细胞纯度达到90%以上;流式细胞术检测显示传至第3代继续培养72h后的BMMSC高表达CD44、CD29,而HLA-DR、CD45、CD34表达阴性,说明所培养的BMMSC纯度很高;Transwell培养板培养CD34+细胞与BMMSC,在倒置显微镜下观察以及自动细胞计数仪计数发现,实验组有活性的CD34+细胞数量高于对照组(P<0.05);采用MTT比色法检测骨髓CD34+细胞的增殖活性,实验组高于对照组(P<0.05)。以上结果说明BMMSC有促进骨髓CD34+细胞增殖的作用,这种作用可能与其分泌的细胞因子有关。     

IL-15对骨髓增生异常综合征患者CD34+细胞增殖、分化的影响

目的 探讨IL-15对体外培养的骨髓增生异常综合征(MDS)患者CD34+细胞增殖和分化的影响.方法 应用单克隆抗体(mAb)免疫磁珠系统分离CD34+细胞, 将实验分为加IL-15的实验组和不加IL-15的对照组, 分别用液体培养基和甲基纤维素半固体培养基培养.计数培养后的细胞数和CFU-E、BFU-E、CFU-GM和CFU-GEMM的集落形成数,并用MTT比色法检测IL-15对MDS 患者CD34+细胞增殖的抑制作用.用流式细胞术检测上述培养的细胞上各种表型分子CD33、 CD13、 CD71、 CD19和CD3表达的变化和细胞周期的改变.结果 11例MDS患者CD34+细胞的平均回收率为(75.4±5.2)%, CD34+细胞的纯度为(90.3±6.3)%.富集倍数为(83.1±12.5)倍.用MTT比色法检测表明, IL-15抑制CD34+细胞增殖的最佳剂量为20 μg/L, 最佳时间为8 d.将对照组及20 μg/L 的IL-15(实验组)分别与MDS患者的CD34+细胞共培养8 d, 进行细胞计数显示, 增殖倍数对照组为4.6倍, 实验组为6.3倍(P＜0.05, n＝5); 各祖细胞的集落形成率, 实验组均明显多于对照组.CD34+细胞上各种表型分子的表达率(除CD3外), 实验组均明显高于对照组.IL-15作用后, CD34+细胞的细胞周期中G1、S、G2期的比率均有明显变化, 与对照组相比较, 差异显著(P＜0.05, n＝7).结论 IL-15对MDS患者的CD34+细胞具有明显地促增殖和诱导分化的效应, 对MDS患者的治疗可能开阔了广大的前景.     

TMB-8对小鼠T淋巴细胞体外活化、增殖和细胞周期的影响

目的: 研究胞内钙离子释放阻断剂8- (N,N-二乙胺) 辛基-3,4,5-三甲氧基苯甲酸酯（TMB-8）对刀豆蛋白A（Con A）介导的小鼠T淋巴细胞体外活化、增殖和细胞周期的影响。方法: 以Con A作为T细胞活化、增殖的刺激剂，以不同浓度的TMB-8及与环孢菌素A（CsA）联合作用于该系统，用流式细胞术检测T细胞早期活化标志CD69分子的表达；以活体染料羧基荧光素乙酰乙酸（CFDA-SE）染色流式细胞术，分析TMB-8在Con A刺激下小鼠淋巴细胞的增殖相关指数（PI）；以碘化丙啶染色分析细胞周期的分布情况。结果: Con A作用6 h后，CD69+ T细胞的比率为（74.88±1.88）%，TMB-8在终浓度10、20、40 μmol/L下均抑制Con A介导的T细胞CD69表达（P<0.01），其中，40 μmol/L的TMB-8为（52.55±1.54）%, 达到最高抑制率。培养48 h和72 h，Con A刺激下的PI值分别为1.24±0.01和2.05±0.07，TMB-8从5 μmol/L起均抑制Con A介导的淋巴细胞增殖（P<0.01），以40 μmol/L的效果最为显著，PI值分别为1.01±0.01和1.10±0.01；10 μmol/L的TMB-8与25 μg/L的环孢菌素A（CsA）具有明显的协同抑制作用（P<0.01）。细胞周期分析显示，培养48 h的TMB-8从10 μmol/L起即显著抑制S期（P<0.01）。结论: TMB-8可明显抑制Con A介导下的T细胞早期活化及增殖，并具T细胞周期的S期阻滞作用。     

用CD133免疫磁珠分离脐血内皮祖细胞的实验研究

目的：从脐血中分离、培养血管内皮祖细胞,研究内皮祖细胞的生长特性和诱导分化条件。 方法： 应用MACS磁球抗体标记法纯化脐血中的CD133+细胞，通过流式细胞仪、免疫细胞化学、免疫荧光等技术及形态学（光镜、电镜）观察研究内皮祖细胞；将细胞接种于添加（或未添加）VEGF、bFGF、干细胞因子（SCF）的含20％胎牛血清（FBS）的IMDM培养基中,观察内皮祖细胞的生长特性。 结果： 分离新鲜脐血所得CD133阳性细胞占单个核细胞的(1.41±1.14)%,经流式细胞仪鉴定CD133+细胞纯度为75%-85%；将分离细胞接种于纤维连接蛋白包被的24孔板内，培养1-2 h即有细胞贴壁，7-10 d可见贴壁细胞呈铺路石样排列；14 d后细胞出现小圆形、梭形等多样性变化，可见毛细血管管腔样结构，电镜观察可见胞浆内典型的Weibel-Palade小体；在VEGF、bFGF、SCF存在条件下,检测贴壁细胞培养14 d后细胞表面抗原表达情况：与培养开始时相比，祖细胞标志CD133和CD34阳性率呈明显下降趋势，分别由(77.0±3.3)%和(93.1±4.7)%降至(1.6±2.2)%和(37.4±4.9)%，P<0.05，内皮细胞特异性标志Flk-1表达明显增加，由(22.3±3.3)%增至(94.3±4.1)%，P<0.05，同时vWF抗原呈强阳性表达，阳性率为(77.9±3.3)%。 结论： 根据细胞表面特异性分子标志（CD133+/CD34+/Flk-1+）可以从脐血中分离出EPCs，EPCs可在体外一定的诱导因子作用下，培养7-10 d分化为成熟内皮细胞。     

骨髓CD34+细胞体外扩增诱导树突状细胞实验研究

目的探讨应用不同细胞因子组合方案从骨髓CD34+细胞体外扩增诱导树突状细胞(DC)的可行性及评价不同诱导方案诱导DC的效果.方法免疫磁珠法纯化骨髓CD34+细胞.在有血清条件下应用两步法SCF+FL+TPO+IL-3扩增2周,然后以GM-CSF+IL-4+TNF-α(GI方案)或GM-CSF+TNF-α(GT方案)诱导DC;或者一步法SCF+FL+TPO+IL-3+GM-CSF+TNF-α直接作用2周扩增诱导DC.通过相差显微镜、电子显微镜、流式细胞仪分析、异硫氰酸荧光素标记的葡聚糖(FITC-DX)内吞实验检测DC的生物学特性.结果诱导后细胞较0 d或诱导前细胞高表达DC相关标记(CD1a、CD80、CD86、CD40、CD54、HLA-DR).两步法GI方案诱导10 d,总细胞扩增倍数、CDla+DC扩增倍数分别为(198±178)倍和(122±129)倍,与GT方案比较无统计学意义,但诱导细胞CD1a、CD80、CD86的表达明显高于后者.一步法扩增诱导2周时总细胞数扩增(43±16)倍,CD1a+DC数是0 d接种细胞的(4±2)倍.结论两步法能从正常CD34+细胞诱导产生大量DC,GI方案优于GT方案.两者扩增效率均优于一步法.     

Small peptide analogue of SDF-1alpha supports survival of cord blood CD34+ cells in synergy with other cytokines and enhances their ex vivo expansion and engraftment into nonobese diabetic/severe combined immunodeficient mice

The SDF-1/CXCR4 axis has been implicated in the chemotaxis, homing, mobilization, and expansion of hematopoietic stem and progenitor cells. We studied the effects of a SDF-1 peptide analogue CTCE-0214 on the survival of cord blood CD34+ cells in culture, expansion, and engraftment of expanded cells in the nonobese diabetic/severe combined immunodeficient (NOD/SCID) mouse model. Our results demonstrated that CTCE-0214 synergized with thrombopoietin (TPO), stem cell factor (SCF), or flt-3 ligand (FL) on the survival of stem and progenitor cells in culture. Adding CTCE-0214 at a low concentration (0.01 ng/ml) for 4 days together with TPO, SCF, and FL significantly enhanced ex vivo expansion of CD34+ cells to subsets of primitive (CD34+CD38- cells, colony-forming unit-mixed [CFU-GEMMs]), erythroid (CFU-Es), myeloid (CFU-GMs), and megakaryocytic (CD61+CD41+ cells, CFU-MKs) progenitors, as well as their multilineage engraftment in NOD/SCID mice. Interestingly, the short exposure of expanded cells to CTCE-0214 (100 and 500 ng/ml) for 4 hours did not increase the quantity of progenitor cells but enhanced their engraftment capacity. The proportion of CD34+ cells expressing surface CXCR4 was decreased, but the overall number of this population increased upon expansion. The small peptide analogue of SDF-1 could be developed for ex vivo expansion and improving engraftment of cord blood transplantation.     

血管内皮祖细胞的体外扩增特性研究

目的:探讨血管内皮祖细胞(EPCs)在体外扩增特性。方法:利用磁性活化细胞分选系统(MACS)系统富集CD34⁺细胞,在相同条件下与同批的单个核细胞(MNC)、CD34⁺和CD34^-混和细胞进行对照培养,比较EPCs体外扩增效果。另外研究血管内皮生长因子(VEGF)和传代培养对细胞分化、扩增动力学和细胞凋亡的影响。应用细胞免疫化学和流式细胞术对细胞定性定量分析。结果:MNC培养、CD34⁺和CD34^-细胞混和培养明显高于CD34⁺细胞单独培养EPCs扩增率(P＜0.05),一旦细胞形成线索样结构行传代培养明显低于未传代的细胞凋亡(P＜0.05)。VEGF对细胞凋亡(P＞0.05)无明显影响,这些分化的EPCs免疫细胞化学染色CD34、vWF、KDR、CD31阳性,并且吞噬乙酰化低密度脂蛋白(Ac-LDL)。培养7d流式细胞检查CD34⁺、AC133^＋分别占贴壁(AT)细胞的68.2%±6.3%(n=6)、57.2%±9.8%(n=6)。结论:MNC培养、CD34⁺和CD34^-细胞混和培养提高了EPCs扩增率,早传代使凋亡率明显降低。VEGF对EPCs体外扩增无明显影响。     

转JAK2基因脐血CD34+细胞体外扩增与生物学特性研究

目的： 探讨转基因JAK2介导的脐血干祖细胞长期扩增调控的可行性和转基因细胞的生物学特征。方法: 构建逆转录病毒载体MGI-F₂JAK2，内含有JAK2基因的功能催化区和2个与小分子靶向基因合成药物(AP20187)结合的位点蛋白(F36v，F₂)。应用MiniMACS磁珠分选系统纯化分离脐血CD34⁺细胞，用含JAK2的逆转录病毒上清转染脐血CD34⁺细胞。转染后的CD34⁺细胞在IMDM培养体系中，将细胞分为AP20187组;FL组；TPO组；AP20187+FL+TPO (AFT) 组。对扩增后的细胞定期检测基因转移后GFP动态变化、细胞免疫标记、造血祖细胞集落培养、染色体核型分析和裸鼠致瘤实验。结果: 分选的CD34⁺细胞纯度>91%，基因转移率为49.32%±6.21%；只有AP20187+FL+TPO组可以使转基因的脐血CD34⁺细胞大量增殖，扩增至第8周时细胞数达10⁹，CD34⁺细胞GFP的阳性率由基线水平逐渐上升并于第8周时达到90%以上；细胞表型为CD33⁺、CD61⁺、Gly-A⁺部分阳性；CD38⁺、HLA-DR⁺强阳性；CD2、CD7、CD19接近阴性。扩增的CD34+细胞可分别形成BFU-E、CFU-GM、CFU-Mix并以CFU-GM集落为主。扩增后CD34⁺细胞检测染色体核型正常，裸鼠实验无致瘤特性。结论: 转染JAK2 基因的人脐血CD34⁺细胞协同FL和TPO细胞因子可以体外长期扩增脐血干祖细胞，对今后研究细胞信号转导、造血调控以及开展干细胞和基因治疗都有潜在的应用价值。     

T淋巴细胞清除促进脐血造血细胞的体外扩增

采用抗CD3或抗CD8单克隆抗体的补体细胞毒方法清除脐血单个核细胞 (MNC )中T淋巴细胞 ,CD34免疫亲和柱纯化MNC中CD34 +细胞 ,流式细胞技术 (FACS )分析细胞表面标志。将CD34 +细胞中加入含多种造血生长因子的培养基进行体外液态扩增 ,并观察粒 巨噬集落 (CFU GM )和多向祖细胞集落 (CFU GEMM )形成能力。结果CD3+或CD8+细胞清除组和MNC经CD34免疫亲和柱纯化后 ,CD34 +细胞分别为 5 9 5 2 %、 5 6 70 %和 5 0 72 % ,比未纯化组 (1 0 7% )纯度大幅度提高。抗CD3单抗清除 +CD34纯化组和单纯CD34纯化组经造血生长因子刺激培养第 14天 ,细胞总数分别扩增 110 40倍和 87 0 0倍。抗CD3单抗清除 +CD34纯化组、抗CD8单抗清除 +CD34纯化组和单纯CD34纯化组的CFU GM产率分别为 2 86 5 0± 12 0 2、2 88 5 0± 17 68和 2 19 5 0± 5 3 0 3,前者虽高于后者 ,但差异无显著性。CFU GEMM产率分别为 376 67± 43 2 4、 438 33± 36 73和 311 0 0± 40 11,抗CD3单抗清除 +CD34纯化组无显著差异 ,抗CD8单抗清除 +CD34纯化组显示出显著性作用 (P <0 0 5 )。     

Umbilical Cord Mesenchymal Stem Cells Increase Expansion of Cord Blood Natural Killer Cells

Natural killer (NK) cell-mediated cytotoxicity can control leukemia relapse while protecting patients from graft-versus-host disease (GVHD) after allogeneic stem cell transplant. Cord blood (CB) is rich in NK cell progenitors with similar properties of proliferation and cytotoxicity as adult blood NK cells. Hence, it is attractive to expand and potentially utilize these cells for adoptive immunotherapy. In this study, CB mononuclear cells were CD3-depleted by immunomagnetic microbead selection to remove T cells. This CD3^dep CB-MNC fraction was then plated for ex vivo expansion, with or without a feeder layer of irradiated umbilical cord mesenchymal stem cells (UC-MSC), with or without cytokines that have been shown to be critical for NK expansion: IL-2, IL-15, IL-3, and FLT-3L. At an average of 2 weeks of culture, there was significantly higher expansion (64.7 ± 8.4-fold) of CD56⁺/CD3⁻ NK cells in the presence of the UC-MSC feeder layer and cytokines compared to controls (no increase with feeder layer only and 6.4 ± 1.5-fold increase with cytokines only, P < .05). Contact between CD3^dep CB-MNC cells and UC-MSC augmented NK expansion. The combination of all 4 cytokines was superior to IL-2 alone or 2 cytokines combinations: mean 64.7 ± 8.4-fold expansion with 4 cytokines combination versus IL-2 alone, IL-2 + FLT-3L, IL-2 + IL-15 or IL-2 + IL-3 (12.2 ± 2.0, 14.4 ± 2.4, 10.4 ± 4.1, 25.2 ± 8.1 respectively). We also observed that only fresh CD3^dep CB-MNC preparations could be expanded reliably, whereas frozen and thawed CD3^dep CB-MNC cells did not expand consistently (mean fold increase 6.5 ± 3.2). Cytotoxicity of expanded NK cells was compared with NK cells from fresh and overnight IL-2 activated CD3^dep CB-MNC. Whereas fresh cells displayed no discernible killing, strong cytotoxicity against K562, Raji, REH, and SUP-B15 cells lines was noted after overnight activation in IL-2. Cytotoxicity of expanded NK cells against Raji, REH, and SUP-B15 was lower, which, however, correlated with a predominant expansion of CD56⁺/CD16⁻ cells known to have less cytolytic activity than CD56⁺/CD16⁺. To test the transfection efficiency in NK cells, fresh or expanded CD3^dep CB-MNC cells were electroporated with either DNA or mRNA constructs for GFP. DNA had a low transfection efficiency (<10%), whereas the one for mRNA reached 52%, but at the cost of significant cell death. Our results suggest that CB NK cell progenitors can be expanded to obtain large numbers by using an irradiated feeder of UC-MSC. They maintain an elevated cytotoxic profile, and may be genetically manipulated—all characteristics that make them suitable for cellular therapies.     

Differential kinetics of primitive hematopoietic cells assayed in vitro and in vivo during serum-free suspension culture of CD34+ blood progenitor cells.

So far, blood progenitor cells (BPC) expanded ex vivo in the absence of stromal cells have not been demonstrated to reconstitute hematopoiesis in myeloablated patients. To characterize the fate of early hematopoietic progenitor cells during ex vivo expansion in suspension culture, human CD34(+)-enriched BPC were cultured in serum-free medium in the presence of FLT3 ligand (FL), stem cell factor (SCF) and interleukin 3 (IL-3). Both CD34 surface expression levels and the percentage of CD34+ cells were continuously downregulated during the culture period. We observed an expansion of colony-forming units granulocyte-macrophage (CFU-GM) and BFU-E beginning on day 3 of culture, reaching an approximate 2-log increase by days 5 to 7. Limiting dilution analysis of primitive in vitro clonogenic progenitors was performed through a week 6 cobblestone-area-forming cell (CAFC) assay, which has previously been shown to detect long-term bone marrow culture-initiating cells (LTC-IC). A maintenance or a slight (threefold) increase of week 6 CAFC/LTC-IC was found after one week of culture. To analyze the presence of BPC mediating in vivo engraftment, expanded CD34+ cells were transplanted into preirradiated NOD/SCID mice at various time points. Only CD34+ cells cultured for up to four days successfully engrafted murine bone marrow with human cells expressing myeloid or lymphoid progenitor phenotypes. In contrast, five- and seven-day expanded human BPC did not detectably engraft NOD/SCID mice. When FL, SCF and IL-3-supplemented cultures were performed for seven days on fibronectin-coated plastic, or when IL-3 was replaced by thrombopoietin, colony forming cells and LTC-IC reached levels similar to those of control cultures, yet no human cell engraftment was recorded in the mice. Also, culture in U-bottom microplates resulting in locally increased CD34+ cell density had no positive effect on engraftment. These results indicate that during ex vivo expansion of human CD34+ cells, CFC and LTC-IC numbers do not correlate with the potential to repopulate NOD/SCID mice. Our results suggest that ex vivo expanded BPC should be cultured for limited time periods only, in order to preserve bone-marrow-repopulating hematopoietic stem cells.     

Expansion of engrafting human hematopoietic stem/progenitor cells in three-dimensional scaffolds with surface-immobilized fibronectin

An efficient and practical ex vivo expansion methodology for human hematopoietic stem/progenitor cells (HSPCs) is critical in realizing the potential of HSPC transplantation in treating a variety of hematologic disorders and as a supportive therapy for malignant diseases. We report here an expansion strategy using a three-dimensional (3D) scaffold conjugated with an extracellular matrix molecule, fibronectin (FN), to partially mimic the hematopoietic stem cell niche. FN-immobilized 3D polyethylene terephthalate (PET) scaffold was synthesized and evaluated for HSPC expansion efficiency, in comparison with a FN-immobilized 2D PET substrate and a 3D scaffold with FN supplemented in the medium. Covalent conjugation of FN produced substrate and scaffold with higher cell expansion efficiency than that on their unmodified counterparts. After 10 days of culture in serum-free medium, human umbilical cord blood CD34+ cells cultured in FN-conjugated scaffold yielded the highest expansion of CD34+ cells (approximately 100 fold) and long-term culture initiating cells (approximately 47-fold). The expanded human CD34+ cells successfully reconstituted hematopoiesis in NOD/SCID mice. This study demonstrated the synergistic effect between the three-dimensionality of the scaffold and surface-conjugated FN, and the potential of this FN-conjugated 3D scaffold for ex vivo expansion of HSPCs.     

Human Wharton’s Jelly Stem Cell Conditioned Medium Enhances Freeze-Thaw Survival and Expansion of Cryopreserved CD34+ Cells

Hematopoietic stem cells (HSCs) from umbilical cord blood have been successfully used to treat blood disorders but one major hurdle is the relatively low cell dose available. Double cord blood unit transplantation results in elevated engraftment failure because one unit predominates over the other. Various approaches are thus being undertaken to expand HSCs ex vivo from single cord blood units. We report here a protocol involving slow freezing (?1 °C per minute to ?120 °C) + freezing medium containing DMSO + FBS + 24 h-50 % hWJSC-CM that enhances thaw-survival of CD34+ cells. Post-thawing, the fold, percentage and colony forming unit numbers of CD34+ cells were significantly increased (2.08?±?0.3; 102?±?1.17 %; 1.07?±?0.02 respectively) while the percentages of apoptotic, necrotic, dead and sub-G1 phase cells (91.06?±?3.63 %; 91.80?±?5.01 %; 95.6?±?3.61 %; 86.1?±?16.26 % respectively) were significantly decreased compared to controls. Post-thaw culture in 24 h-50 % hWJSC-CM+FBS for 72 h showed further significant increases in CD34+ cells (fold: 2.28?±?0.17; percentage: 153.3?±?21.99 %, CFU: 1.6?±?0.19) and significant decreases in apoptotic, necrotic, dead and sub-G1 cells (49.2?±?3.59 %; 62.0?±?4.30 %; 56.6?±?5.06 %; 28.6?±?5.74 % respectively) compared to controls. We hypothesize that these improvements are probably related to the high levels of cytokines, cell adhesion molecules and growth factors in hWJSC-CM that help to preserve cell membrane integrity during freezing and stimulate mitosis post-thaw. A 24 h-50 % hJWSC-CM may be a useful supplement for freezing CD34+ cells in cord blood banks.