Differential transduction efficiency of SCID-repopulating cells derived from umbilical cord blood and granulocyte colony-stimulating factor-mobilized peripheral blood.

The gene transfer efficiency into nonobese diabetic/severe combined immunodeficient (NOD/SCID)-repopulating cells (SRCs) derived from umbilical cord blood (UCB) (n = 11 NOD/SCID mice) and granulocyte-colony stimulating factor (G-CSF)-mobilized peripheral blood (MPB) (n = 64 NOD/SCID mice) was compared using a clinically relevant protocol and a retrovirus vector expressing the enhanced green fluorescent protein (EGFP). At 6-9 weeks after transplantation, the frequency of transduced human cells in the bone marrow (BM) (40.5% +/- 2.4% [mean +/- SE]) and spleen (SPL) (36.4% +/- 3.2%) in recipients of UCB cells was significantly higher (p < 0.001) than that observed in the BM (2.2% +/- 1.8%) and SPL (2.0% +/- 2.6%) in recipients of MPB. In subsequent studies, MPB was cultured for 2-8 days in cytokines prior to transduction to determine if longer prestimulation was required for optimal gene transfer. A significant increase in gene transfer into CD45(+) human cells and clonogenic cells derived from MPB SRCs was observed when cells were prestimulated for 6 days compared to 2 days prior to transduction (p = 0.019). However, even after 6 days of prestimulation, transduction was still significantly less than UCB. A substantial discrepancy exists in the ability to introduce genes effectively via retrovirus vectors into SRCs derived from MPB as compared to UCB.     

不同来源人造血干/祖细胞在NOD/SCID小鼠体内归巢能力的差异

目的 比较不同来源的人造血干／祖细胞在NOD／SCID小鼠体内归巢能力的差异性，并探讨其体内归巢能力与膜表面归巢相关分子CXCR4表达水平的相关性。方法 采用流式细胞术（FACS）检测新鲜脐血、冻存脐血、动员后外周血（mPB）及骨髓来源的CD34^＋细胞表面CXCR4表达水平；将荧光染料CFSE标记的人CD34^＋细胞移植人接受照射的NOD／SCID小鼠，移植后20小时检测已归巢于NOD／SCID小鼠骨髓及脾脏中不同来源的人CD34^＋细胞，计算其相应的骨髓及脾脏归巢效率；并将小鼠股骨制成组织切片，荧光显微镜下观察人CD34^＋细胞在小鼠骨髓腔内的分布。结果 新鲜脐血、冻存脐血、mPB和骨髓CD34^＋细胞膜表面CXCR4表达阳性率分别为（49.52±1．12）％。（46．12±2．29）％，（48．50±2．48）％和（65．39±1．27）％，CD34^＋细胞在NOD／SCID小鼠骨髓的归巢效率分别为（3．00±0．44）％，（2．84±0．46）％，（4．06±0．70）％及（5．76±0．52）％；在脾脏的归巢率分别为（1．88±0．12）％，（1．80±0．15）％，（1．90±0．22）％，（2．16±0．34）％。归巢的CD34^＋细胞主要分布于小鼠股骨的骨内膜区域。结论 脐血CD34^＋细胞膜表面CXCR4水平低于mPB和骨髓。经冻存复苏后脐血CD34^＋细胞膜表面CXCR4水平略有下调。脐血CD34^＋细胞在照射NOD／SCID小鼠的骨髓归巢效率低于mPB和骨髓。     

间充质干细胞与人脐血CD34+细胞共移植对NOD/SCID小鼠造血重建的影响

目的 观察间充质干细胞(MSC)与不同比例脐血CD34+细胞共移植对NOD/SCID小鼠造血重建的影响,明确MSC与脐血CD34+细胞共移植的最适数量.方法 给60Coγ射线照射的雌性NOD/SCID小鼠共移植人MSC和不同比例的脐血CD34+细胞,观察共移植后42 d内小鼠外周血白细胞和血小板变化,并于移植后42 d处死小鼠,用流式细胞术检测外周血、骨髓和脾脏人源细胞含量.结果 与单纯脐血CD34+细胞移植相比较:①脐血CD34+细胞与1、5和10倍数量的MSC共移植时,可明显减轻外周血白细胞和皿小板的下降幅度(P<0.01),提前1周使白细胞和血小板恢复至正常水平(P<0.05),三组间差异无统计学意义(P>0.05);②MSC与不同比例的脐血CD34+细胞共移植均可明显提高外周血、骨髓和脾脏造血细胞植入率.比例为10:1时,外周血、骨髓和脾脏中的人源细胞(huCD45+细胞)含量分别增加了(2.8±0.6)倍、(3.5±0.9)倍和(5.2±0.6)倍,增加倍数差异均有统计学意义(P<0.01),达到了最佳的植入效果.结论 脐血CD34+细胞与10倍数量的MSC共移植可达到最佳的促进造血重建作用.     

脐血造血干/祖细胞免疫表型的流式细胞术双标法分析及其意义

目的比较脐血和骨髓中造血干/祖细胞(HSPC)的免疫表型差异.方法使用流式细胞术(FCM)双标法对38份脐血及10份骨髓HSPC进行免疫表型分析.结果①脐血有核细胞中CD34+细胞所占比例与骨髓中相近,约为0.5%;②脐血CD34+细胞中CD34+CD38-[(17.C4±5.37)%]、CD34+HLA-DR-[(32.65±10.71)%]及CD34+H-CAM+(CD44+)[(77.84±7.69)%]亚群含量均高于骨髓[含量分别为(8.26±3.19)%、(14.05±1.67)%和(70.02±6.40)%],CD34+CD13+、CD34+CD19+亚群比例低于骨髓.结论脐血与骨髓CD34+细胞比例相近,但前者较原始的干细胞含量更高,故脐血是极具潜力的HSPC来源;而脐血CD34+细胞中髓系及淋系祖细胞含量低于骨髓,可能是脐血移植后造血及免疫重建缓慢的原因之一.     

基质细胞衍生因子-1及其受体在G-CSF诱导的造血干/祖细胞动员中的作用

目的探讨基质细胞衍生因子-1（SDF-1）及其特异性受体CXCR4在G-CSF诱导的造血干／祖细胞（HSPC）动员中的作用。方法应用酶联免疫吸附实验（ELISA）、免疫组织化学、流式细胞术等方法检测健康供者稳态及G-CSF动员过程中骨髓、外周血SDF-1／CXCR4的变化，并应用SDF-1中和性抗体阻断BALB／c小鼠SDF-1信号通路，进一步验证SDF-1／CXCR4在动员中的作用。结果G-CSF动员前骨髓和外周血的SDF-1浓度分别为（7．23±0．66）μg/L和（5．43±0．35）μg／L，动员后分别为（5．88±1．03）μg／L和（5．42±0．52）μg/L。动员后骨髓SDF-1蛋白水平下降（P＜0．05），骨髓和外周血之间的SDF-1浓度梯度消失（P＞0．05）；稳态骨髓、动员后骨髓和动员后外周血的CD34^＋ CXCR4^＋细胞在CD34^＋细胞群中的比例分别为（40．98±21．56）％、（65．80±24．68）％和（27．54±26．03）％。动员后CXCR4在骨髓CD34^＋胞上表达增加（P＜0．05），而外周血CD34^＋细胞CXCR4表达降低（P＜0．05）。SDF-1中和性抗体可降低G-CSF动员的BALB／c小鼠外周血成熟白细胞和祖细胞集落数量（P＜0．05）。结论骨髓中SDF-1水平的降低以及CXCR4在HSPC上表达的下降促进了G-CSF介导的动员的发生。     

不同来源的造血干/祖细胞表面归巢相关分子表达谱的比较研究

目的　比较不同来源的造血干 /祖细胞表面归巢相关分子 (HRM)表达谱的差异性。方法　采用高度灵敏的四色流式细胞术检测脐血 (UCB)、动员后的外周血 (mPB)及骨髓 (BM)来源的造血干 /祖细胞表面系列HRM表达水平。结果　UCB、mPB及BM来源的CD34bright细胞均高度表达黏附分子CD4 4、CD11a、CD18、CD6 2L、CD31及CD4 9d ;但UCB来源的CD34bright细胞及CD34brightCD38-细胞黏附分子CD4 9e、CD4 9f、CD5 4及趋化因子受体CXCR 4的表达水平显著低于mPB及BM来源者 ;上述不同来源的造血干 /祖细胞均不表达其他趋化因子受体 ,包括CCR 1、CCR 2、CCR 3、CCR 5、CXCR 1、CX CR 2、CXCR 3及CXCR 5 ;更为有意义的是 ,只有mPB来源的CD34bright细胞表达基质金属蛋白酶MMP 2及MMP 9。CD34brightMMP 2 及CD34brightMMP 9 细胞百分率分别为 (11.4± 4 .9) %及 (2 7.6± 7.8) %。结论　UCB来源的造血干 /祖细胞低表达或不表达某些HRM ,这可能是UCB移植后造血重建延迟的原因之一。     

Ex vivo expansion of CD34+ umbilical cord blood cells in a defined serum-free medium (QBSF-60) with early effect cytokines

To investigate the clinically applicable conditions that support substantial expansion of both primitive and more mature hematopoietic cells of umbilical cord blood (UCB) for transplantation in adults, enriched CD34+ cells from 8 fresh UCB samples and 4 expanded UCB products were cultured in defined serum-free medium (QBSF-60) in the presence of a cytokine combination of SCF, Flt-3-ligand (FL), thrombopoietin (TPO), IL-3 for up to 2 weeks. Fresh medium with cytokines was supplemented or exchanged at day 4, day 7, and day 10. The proliferative response was assessed at day 7, day 10, and day 14 by evaluating the following parameters: nucleated cell (NC), clonogenic progenitors (colony-forming unit-granulocyte-macrophage [CFU-GM], burst-forming unit-erythrocyte [BFU-E], CFU-GEMM, and high-proliferative potential colony-forming cell [HPP-CFC]), immunophenotypes (CD34+ cells and CD34+ subpopulations), and LTCIC. Simultaneously numerical expansion of various stem/progenitor cells, including primitive CD34+CD38-HLA-DR- subpopulation and LTCIC, CD34+ cells, and clonogenic progenitors to mature nucleated cells, were continuously observed during the culture. An average 103.32 +/- 71.37 x 10(6) CD34+ cells (range 10.12 x 10(6)-317.9 x 10(6)) could be obtained from initial 1.72 +/- 1.13 x 10(6) UCB CD34+ cells after 10-14 days cultured under the described conditions. Sufficient CD34+ cells (>50.0 x 10(6)) for transplantation in adults would be available in all but one UCB collections after 10-14 days expansion. The expanded CD34+ cells sustained most of the in vitro characteristics of initial unmanipulated CD34+ cells, including clonogenic efficiency (of both primitive and committed progenitors), the proportion of CD34+CD38-HLA-DR- subpopulation, and the expansion potential. Initial addition of IL-3 to the cocktail of SCF + FL + TPO had positive effects on the expansion of both primitive and, especially, the more mature hematopoietic cells. It accelerated the expansion speed and shortened the optimal culture time from 14 days to 10 days. These results indicated that our proposed short-term culture system, consisting of QBSF-60 serum-free medium with a simple early acting cytokine combination of SCF + FL + TPO, could substantially support simultaneous expansion of various stem/progenitor cell populations involved in the different phases of engraftment. It would be a clinically applicable protocol for ex vivo expansion of CD34+ UCB cells.     

p27基因下调对人骨髓和脐血造血祖细胞体外活性的影响

目的比较干扰p27基因表达对骨髓和脐血来源造血祖细胞增殖和造血潜能的影响,并探讨其相关机制。方法以含p27全长反义cDNA逆转录病毒感染经流式细胞仪分选的人骨髓与磁珠分离获得的人脐血来源的CD34+细胞,在含混合生长因子条件下体外培养不同时间,分别观察细胞生长曲线,检测细胞周期,确定细胞增殖能力;半固体培养计数集落形成,确定其造血能力;Westernblot检测p27与CDK2蛋白表达,明确基因转染效果并探讨p27反义cDNA促进细胞扩增的作用途径。以含p27全长正义cDNA和仅含绿色荧光蛋白(GFP)基因的病毒感染细胞为对照。结果与GFP和p27正义cDNA比较,p27反义cDNA对脐血造血祖细胞生长有明显促进作用(P<0.01),至培养第9天p27反义cDNA、p27正义cDNA和GFP组细胞数分别增加了(197.3±47.7)倍、(12.7±8.1)倍和(41.8±30.6)倍;骨髓造血祖细胞数增加不明显,至培养第9天3组细胞数分别增加了(36.0±22.3)倍、(8.7±6.8)倍和(14.1±10.4)倍。p27反义cDNA主要促进脐血和骨髓造血祖细胞S期增加,p27反义cDNA、p27正义cDNA和GFP组脐血造血祖细胞S期细胞百分比为(17.0±4.8)%,(2.0±0.8)%和(4.1±1.8)%;骨髓造血祖细胞则为(8.4±4.4)%,(1.0±0.7)%和(3.8±1.4)%。p27反义cDNA对骨髓和脐血的集落形成能力促进作用高于GFP组(P<0.0     

人脐血及骨髓淋巴细胞免疫表型的比较及其意义

为比较脐血和骨髓淋巴细胞及祖细胞分化抗原，通过流式细胞术（FCM）双标法对38份脐血及10份骨髓免疫细胞表型进行了分析研究。研究发现：（1）脐血及骨髓淋巴细胞中均测到稚淋巴细胞（CD3^-CD4^ )，且前中含量较多，但脐血细胞毒T细胞含量（CTL，CD3^ CD16^ 56^ )低于骨髓；（2）脐血中NK细胞（CD3^-CD16^ 56^ )比例高于骨髓；（3）脐血有核细胞中CD34^ 细胞的比值接近于骨髓，但脐血CD34^ 细胞中髓系祖细胞（CD34^ CD13^ ,CD34^ HLA-DR^ )及淋巴系祖细胞（CD34^ CD19^ )含量均低于骨髓，结论：（1）脐血免疫细胞具有不成熟性，这估计是脐血移植后GVHD程度轻的主要原因；（2）脐血淋巴细胞中NK细胞含量较高，推测脐血移植后移植物抗白血病效应（GVL）并不会降低；（3）脐血CD34^ 细胞中髓系祖细胞及淋巴系祖细胞比例均低于骨髓，可能是脐血移植后造血及免疫重建速度较慢的原因之一。     

Processing of major ABO-incompatible bone marrow for transplantation by using dextran sedimentation

BACKGROUND: Various open and semi-closed methods are used for red cell (RBC) depletion and hematopoietic progenitor cell (HPC) enrichment of bone marrow (BM) in vitro, but with variable efficacy. A simple, efficient, and safe method using dextran 110k was developed. STUDY DESIGN AND METHODS: An equal volume of 4.5-percent dextran was applied to major ABO-incompatible BM in transfer bags and sedimentation was allowed for 30 minutes. RBCs, nucleated cells (NCs), and mononuclear cells (MNCs) from BM allografts before and after dextran sedimentation (DS) were counted. Flow cytometry, short-term cultures, and long-term cultures were performed to assay the respective recovery of CD34+ cells, colony-forming units (CFUs), and long-term culture-initiating cells (LTC-ICs). RESULTS: Sixteen BM collections were processed.The mean volume was 666 mL (range, 189-1355 mL).The mean +/-1 SD post-DS NC, MNC, CD34+ cell, and CFU counts per kg of the recipient's body weight were 4.11 +/-1.74 x 10(8), 8.98 +/- 3.68 x 10(7), 2.90 +/- 1.95 x 10(6), and 2.03 +/- 2.01 x 10(5), respectively, with the corresponding post-DS recovery being 90.6 percent, 90 percent, 92.4 percent, and 100.8 percent. The numbers of LTC-ICs in cultures (up to 12 weeks) of pre-DS and post-DS samples of five BM allografts were comparable (p = 0.91). Residual RBCs were 5.1 +/- 4.6 (0.1-14) mL with depletion of 96.5 +/- 3.2 percent. There was no significant difference in the mean absolute RBC count in post-DS BM allografts and in four ficoll-treated BM allografts (8.09 x 10(10) vs. 4.9 x 10(9); p = 0.206) and in eight major ABO-incompatible peripheral blood HPC collections (8.09 x 10(10) vs. 9.81 x 10(10); p = 0.87). No posttransplant hemolysis was encountered. Engraftment occurred at 22 +/- 7 days, which is similar to that of four transplants with ficoll-treated BM allografts (22 +/- 9; p = 0.611) and 54 unprocessed BM allografts (19 +/- 6; p = 0.129). CONCLUSION: DS is an efficient method of depleting RBCs in major ABO-incompatible BM allografts without significant loss of HPCs.     

Megakaryocyte ex vivo expansion potential of three hematopoietic sources in serum and serum-free medium.

Megakaryocytes (MK) were expanded from purified human CD34+ cells obtained from three sources, bone marrow (BM), mobilized peripheral blood progenitor cells (PB), and umbilical cord (UC) blood. CD34+-selected cells were cultured for 12 days with 10 ng/ml thrombopoietin (TPO), 10 ng/ml IL-3, 10 ng/ml TPO + 10 ng/ml IL-3, or 200 ng/ml promegapoietin (PMP), a chimeric dual agonist of the c-Mpl and human IL-3 receptors. MK production was compared in serum-free versus human serum-supplemented liquid media. PMP and the combination of TPO and IL-3 (TPO + IL-3) increased MK production similarly. Culturing CD34+ cells with PMP in serum-free medium resulted in a twofold increase in MK yield compared with serum-supplemented medium. CD34+ cells from UC proliferated more than those from either BM or PB in liquid culture, resulting in much greater MK production under all conditions. Phenotypic analysis of the uncultured CD34+ cells showed that BM had a higher frequency of CD34+/CD41+ cells than PB or UC. TPO + IL-3 or PMP produced larger and greater numbers of BFU-MK and CFU-MK per seeded CD34+/CD41+ cell from UC than from either BM or PB. Thus, although uncultured CD34+-selected BM cells contained a higher frequency of committed mature MK progenitors, UC CD34+ cells had a greater proliferative capacity and, therefore, were more productive. PMP induced megakaryocytopoietic activity comparable to that achieved with TPO + IL-3 and may be useful for ex vivo expansion of MK for clinical trials.     

In vivo effects of myeloablative alkylator therapy on survival and differentiation of MGMTP140K-transduced human G-CSF-mobilized peripheral blood cells.

High-intensity alkylator-based chemotherapy is required to eradicate tumors expressing high levels of O6-methylguanine DNA methyltransferase (MGMT). This treatment, however, can lead to life-threatening myelosuppression. We investigated a gene therapy strategy to protect human granulocyte colony-stimulating factor-mobilized peripheral blood CD34+ cells (MPB) from a high-intensity alkylator-based regimen. We transduced MPB with an oncoretroviral vector that coexpresses MGMT(P140K) and the enhanced green fluorescent protein (EGFP) (n = 5 donors). At 4 weeks posttransplantation into nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice, cohorts were not treated or were treated with low- or high-intensity alkylating chemotherapy. In the high-intensity-treated cohort, it was necessary to infuse NOD/SCID bone marrow (BM) to alleviate hematopoietic toxicity. At 8 weeks posttreatment, human CD45+ cells in the BM of mice treated with either regimen were EGFP+ and contained MGMT-specific DNA repair activity. In cohorts receiving low-intensity therapy, both primitive and mature hematopoietic cells were present in the BM. Although B-lymphoid and myeloid cells were resistant to in vivo drug treatment in cohorts that received high-intensity therapy, no human CD34+ cells or B-cell precursors were detected. These data suggest that improved strategies to optimize repair of DNA damage in primitive human hematopoietic cells are needed when using high-intensity anti-cancer therapy.     

G-CSF-mobilized leukapheresis products: cellular characteristics and clinical performance in allografting.

Twenty-five G-CSF-mobilized leukapheresis products (mLP) were screened for cellular composition, including CD34+DR-, CD34+DR+ and leukocyte profile, to compare with 5 native (unstimulated) LP (nLP) and 16 BM inoculi. G-CSF stimulation led to an increase in CD34+ cells and CD15+ cells but did not influence the lymphocyte content of mLP. Two groups of 14 and 16 patients were allografted with phenotypically defined mLP (1-4 mLP were used for each patient) and BM, respectively. mLP used for allografting had significantly more CD34+ cells, including CD34+DR- cells, monocytes, T cells, and B cells as compared with BM inoculi. Patients were followed for median observation time of 289 days and 409 days for the mLP (PBPC) and BM groups, respectively. The two groups were well matched in regard to age, sex, and stage of disease, with a slight prevalence of major blood group incompatibility (7 of 14 versus 3 of 16) and a lower donor/recipient weight ratio (0.8+/-0.2 vs 1.5+/-0.6, p = 0.002) in the PBPC group. Granulocyte and platelet recovery was faster in the PBPC group than in the BM group. The time of reaching 20,000/microl platelets but not 500/microl granulocytes correlated with the number of CD34+ cells in each inoculum. The survival curves of the PBPC and BM groups were similar, as was the incidence of acute GvHD (aGvHD). This was also valid for aplastic anemia cases (7 and 5 patients in the PBPC and BM group, respectively), who benefited from a high number of CD34+ grafted cells but did not experience aGvHD. Thus, mLP do not appear to elicit aGvHD with higher frequency than BM and may be preferable for hematotherapy.     

Decreased stroma adhesion capacity of CD34+ progenitor cells from mobilized peripheral blood is not lineage- or stage-specific and is associated with low beta 1 and beta 2 integrin expression

Molecular mechanisms leading to mobilization of hematopoietic cells from bone marrow (BM) to peripheral blood (PB) involve modulation of adhesion molecule expression on these cells that probably result in changes in adhesion capacity to the microenvironment. However, it is not clear whether these changes involve different stages or lineages of progenitor cells. In this study, we compared the capacity of mature and immature clonogenic progenitor cells from granulocyte colony-stimulating factor (G-CSF)-mobilized PB and normal BM CD34+ cells to adhere to complete marrow stroma. This functional capacity was assessed concurrently with molecular expression on CD34+ cells of integrins VLA-4 (alpha 4/beta 1), VLA-5 (alpha 5/beta 1), and LFA-1 (alpha L/beta 2) by interindividual (between mobilized PB and normal BM) and intraindividual (between mobilized PB and steady-state BM and PB in the same patient) analysis. The proportion of adherent clonogenic progenitor cells was significantly lower in PB than in BM, not only for total progenitor cells but also for mature and immature progenitor cells, and the difference was found for granulocytic and particularly for erythroid lineages. The lower adhesion capacity of PB CD34+ cells to stroma was associated with decreased expression (signal/noise MFI ratio) of integrin alpha 4, beta 1, alpha L, and beta 2 chains whereas that of alpha 5 chain did not differ from BM cells with the lowest expression level. Similar differences in integrin expression levels were also found between mobilized PB and steady-state BM CD34+ cells in the same patient except for the alpha L chain. Moreover, we demonstrated for the first time a strong positive correlation between mobilizing capacity and expression levels on mobilized CD34+ cells for the LFA-1 alpha L chain but not for VLA-4 or VLA-5. In conclusion, the decreased adhesion capacity of mobilized PB progenitor cells to stroma involves different maturation stages and different lineages. This is associated with down-regulation of integrins VLA-4 and LFA-1, but mobilizing capacity appears positively correlated with LFA-1 levels.     

两步法扩增诱导脐血及动员外周血CD34+细胞来源树突状细胞的比较

为了比较先扩增、后诱导的两步法从脐血(CB)CD34+细胞和动员外周血(MPB)CD34+细胞诱导所得DC的产量及功能,将免疫磁珠分选获得的CB-CD34+细胞和MPB-CD34+细胞用FL、TPO、SCF、GM-CSF等细胞因子先扩增10天,然后加入GM-CSF、IL-4及TNF-α、CD40Ab、PGE2等细胞因子组合诱导获得DC.采用流式细胞仪检测DC表型,混合淋巴细胞培养检测DC刺激异基因T细胞增殖能力,ELISA法检测DC分泌IL-12能力,Transwell板检测DC在次级淋巴组织趋化因子(SLC)介导下的趋化功能.结果表明 ①扩增10天时CB组、MPB组细胞中CD14+CD1a-细胞含量无显著差异[(40.48±16.85)% vs (28.07±23.19)%, P＞0.05].但由于CB组细胞扩增倍数显著高于MPB组(388.88±84.63倍vs 79.67±10.32倍, P＜0.01),CB组CD14+CD1a-细胞扩增倍数显著高于MPB组(189.42±25.02倍vs 28.74±23.27倍, P＜0.01); ②TNF-α/CD40Ab/PGE2条件下与TNF-α条件下相比,CB组和MPB组所得DC均表达更高的CD83[分别为(34.52±11.22)% vs (3.70±2.27)%、(36.69±13.36)% vs (7.34±3.364)%, P均＜0.01]; ③CB组与MPB组在TNF-α/CD40Ab/PGE2诱导条件下所得DC均高水平表达CD83、CD86、HLA-DR、CD11c、CD54、CD40,CB组所得CD83+细胞的扩增倍数显著高于MPB组(198.72±117.53倍vs 33.95±6.19倍,P＜0.01); ④CD40Ab/PGE2/TNF-α条件下CB与MPB来源的DC在刺激异基因T细胞增殖、IL-12的分泌[(16.2±4.31)pg/ml vs (13.5±4.1)pg/ml]以及SLC介导的迁移率[(28.09±7.76)% vs (18.5±3.47)%]上均无显著差别(P均＞0.05).结论 在两步法培养体系下,CB-CD34+细胞与MPB-CD34+细胞来源的DC具有相同的功能,而前者产量显著高于后者.     

No discrepancy between in vivo gene marking efficiency assessed in peripheral blood populations compared with bone marrow progenitors or CD34+ cells

Reports of 1- to 2-log higher gene transfer levels in purified CD34+ cells or marrow CFU compared with levels in mature circulating blood cells after transplantation of retrovirally transduced primitive human hematopoietic cells have resulted in concern that transduced progenitors do not contribute proportionally to ongoing hematopoiesis (Kohn et al., 1995; Brenner, 1996). To study the issue in a relevant large animal, we analyzed samples of mature blood cells, marrow CD34-enriched cells and marrow CD34-depleted cells, and marrow CFU from a cohort of 11 rhesus transplanted with retrovirally transduced cells and followed for up to 5.5 years. They were transplanted with CD34-enriched bone marrow (BM) or G-CSF/SCF-mobilized peripheral blood (PB) cells transduced with vectors containing either neo, human glucocerebrosidase, or murine adenosine deaminase genes. There were no significant differences between the levels of vector sequences found in BM CD34+ cells, BM CD34- cells, PB granulocytes, or PB mononuclear cells (MNCs) in any animal. In four animals transplanted with SCF/G-CSF-primed BM cells and analyzed 3-6 months posttransplantation, the percentage of CFU containing the neo vector appeared to be 1 log higher than the representation of marked cells in the PB of these animals, but this discrepancy did not persist at time points greater than 6 months posttransplantation. The level of CFU marking was no higher than PB granulocyte or MNC marking at any time points in the other animals. Low levels of mature gene-modified cells probably reflect poor transduction of repopulating stem cells, not a block in differentiation or specific immune rejection of mature cells. This study represents the longest follow-up of primates transplanted with transduced hematopoietic cells, and it is encouraging that the levels of vector-containing cells appear stable for up to 5 years.     

人骨髓间充质干细胞体外支持脐血CD34+细胞增殖的研究

为了研究人骨髓间充质干细胞(MSC)作为滋养层细胞体外支持脐血CD34+细胞扩增的作用,将MSC和胎儿骨髓来源的成纤维细胞样骨髓基质细胞系(HFCL)经60Coγ线照射后分别制备细胞滋养层,比较不同滋养层细胞和添加或不加细胞因子对脐血CD34+细胞增殖数及LTC-IC数的影响.结果表明,无论有无添加细胞因子(rhFL、rhSCF、rhTPO),HFCL滋养层组培养12天扩增细胞数明显高于MSC滋养层组,以第0天细胞数为100%(下同),有细胞因子组为(9797±361)%vs(7061±418)%,无细胞因子组为(5305±354)%vs(1992±247)%,均P＜0.01.MSC滋养层组CD34+细胞扩增数与HFCL滋养层组相比无显著差异[(825±305)%vs(820±191)%,P＞0.05],但在细胞因子存在时低于HFCL滋养层组[(939±212)%vs(1617±222)%,P＜0.01].MSC滋养层组维持脐血中LTC-IC的能力明显优于HFCL滋养层组[第5周CFU-GM数(129.95±8.73)个/105接种细胞数vs(89.81±10.29)个/105接种细胞数,P＜0.05];细胞因子存在时,其作用更为明显[第5周CFU-GM数(192.93±4.95)个/105接种细胞数vs(90.47±14.28)个/105接种细胞数,P＜0.01].MSC与HFCL按一定比例混合,可提高扩增效率.当MSC与HFCL之比为41时,集落形成数量最高,达(186.89±11.11)个/105接种细胞数,明显高于比例为32(131.45±13.02)个/105接种细胞数和二者单用组[前者(138.92±14.84)个/105接种细胞数,后者(64.63±6.11)个/105接种细胞数;均P＜0.01].结论MSC维持脐血中LTC-IC集落形成的能力优于基质细胞系HFCL,HFCL支持脐血CD34+细胞的增殖能力优于MSC,MSC加上适量HFCL可显著提高CD34+细胞扩增效率.     

Dextran sedimentation in a semi-closed system for the clinical banking of umbilical cord blood

BACKGROUND: The results of current processing procedures for reducing volume and recovering HPCs from umbilical cord blood (UCB) before cryopreservation vary. STUDY DESIGN AND METHODS: Dextran was added to bags containing UCB, followed by sedimentation for 30 minutes. The processed UCB was then frozen. RBCs, nucleated cells, MNCs, CD34+ cells, CFUs and long-term culture-initiating cells (LTC-ICs), viability, and sterility were evaluated. Fractionations in ficoll-hypaque and hydroxyethyl starch (HES) were also run in parallel for comparison. RESULTS: The nucleated cell (NC) recovery and RBC depletion were 86.1 percent and 94.3 percent, respectively (n = 50). Sedimentation with dextran also enabled the recovery of 80.7 percent MNCs and 82.6 percent CD34+ cells (n = 30). Postsedimentation samples displayed no impairment of CFU growth (n = 42, 108.7% CFU-C, 104.6% CFU-GEMM, 107% CFU-GM, and 95.7% BFU-E). Long-term cultures on five paired samples before and after sedimentation generated similar numbers of CFU-C each week (p = 0.88). Limiting dilution analysis of 12 paired pre/postsedimentation samples showed comparable median proportions of LTC-ICs (1/6494 vs. 1/5236; p = 0.18). The cell viability of 24 samples of thawed UCB after sedimentation was 90.3 percent (77.5-96%) and the recovery of CFU-C, CFU-GEMM, CFU-GM, and BFU-E of 11 postsedimentation samples was 93.4 percent, 84.9 percent, 92.3 percent, and 83.4 percent, respectively. NC recovery was significantly higher after treatment with dextran than with ficoll-hypaque (n = 30; 88.5% vs. 29.1%; p<0.005) and HES treatment (n = 21; 88.5% vs. 76.4%; p = 0.004). However, MNCs, CD34+ cells, CFUs, LTC-ICs, and RBCs were comparable. Two cycles of dextran sedimentation recovered 93.9 percent of NCs with cell viability of 98.6 percent (96.5-100%), whereas 11.7 percent of RBCs were retained (n = 20). The final yield volume was 33.5 (28-41) mL. CONCLUSION: In a semi-closed system, dextran sedimentation enabled volume reduction of UCB without significant quantitative and qualitative losses of HPCs.     

CD34+ cells and CD34+CD38- subset from mobilized blood show different patterns of adhesion molecules compared to those from steady-state blood, bone marrow, and cord blood

As suggested previously, a down-regulation of some cellular adhesion molecules (CAMs) on CD34(+) hematopoietic progenitor cells (HPC) may contribute to their egress from bone marrow (BM) to peripheral blood (PB) by decreasing their adhesion to BM stromal cells. Besides counting the percentage of CAM-positive cells, we decided to define clearly the antigen density (AgD) of the CAM on mobilized- and steady-state CD34(+) HPC using QIFIKIT calibration beads. Five sources of cells were compared: PB and BM from normal donors (nPB, nBM) cord blood (CB), mobilized PB obtained from leukapheresis products (LKP), and mobilized BM (mBM) samples. In our study the CAM-AgD was the lowest on CD34(+) cells in LKP which, on the contrary, contained the highest percentage of CD117(+), CD54(+), CD58(+) cell subsets. As for CB, a greater proportion of CD44(+) and CD62L(+) cells was observed in LKP than in other products. The LKP-CD34(+) cell population contained a greater percentage of CD11a(+) cells when compared to mBM, but the lowest percentage of CD49d(+) and CD49e(+) cells when compared to all products. The proportion of the CD34(+)CD38(-) immature subset expressing CD11a, CD44, CD54, or CD62L was greater in LKP than in mBM; the CD62L-AgD was higher in LKP than in mBM. This quantitative analysis clearly showed a downregulation of all CAM on LKP-CD34(+). The CD44, CD62L, CD11a, and CD54 AgD decrease appears to be specifically involved in the egress of the CD34(+) subsets into PB. The control of antigen density of these adhesion molecules is likely to be clinically important for effective mobilization of HPC as well as for rapid engraftment following HPC transplant.     

Use of merocyanine 540 for the isolation of quiescent, primitive human bone marrow hematopoietic progenitor cells.

Merocyanine 540 (MC540) is a membrane probe that inserts preferentially into loosely packed domains in the phospholipid bilayer of intact cells. Previous experiments have demonstrated that MC540 will bind to human bone marrow (BM) hematopoietic progenitor cells (HPC). Fractions of mononuclear BM cells expressing high MC540 fluorescence have been shown to be enriched for myeloid progenitors and cells residing in the S/G2 + M phases of the cell cycle. We rationalized that MC540 uptake could be used to distinguish between quiescent and metabolically active cells and, therefore, to fractionate normal and leukemic BM cells and normal mobilized peripheral blood (MPB) cells into functionally distinct groups of progenitors. BM and MPB cells were separated into fractions ranging in fluorescence from MC540Bright to MC540Dim. Cell cycle analysis of these fractions revealed that the MC540Dim fraction of normal and CML BM CD34+ cells constituted the most quiescent fraction, and the MC540Bright fractions from these cell types contained the most actively cycling cells. However, no differences in the percentage of cells in G/G1 were observed between MC540Bright and MC540Dim fractions of MPB CD34+ cells. To investigate if these cell cycle status differences translated into distinct functional properties, the hematopoietic potential of BM CD34+MC540Bright and CD34+MC540Dim cell fractions was analyzed in vitro in long-term BM cultures and limiting dilution analysis (LDA) assays. CD34+MC540Dim cells produced more total and committed progenitor cells in long-term cultures than did the CD34+MC540Bright fraction. The CD34+MC540Dim fraction also contained a 2-fold higher number of long-term hematopoietic culture-initiating cells (LTHCIC) than the CD34+MC540Bright fraction, as defined by LDA assays. These data demonstrate that MC540 can be a useful probe for the isolation of primitive HPC from some hematopoietic tissues and may assist in monitoring structural changes in the phospholipid bilayer during proliferation and differentiation of HPC.