脐血体外同时诱导扩增T,NK和CD34+细胞

体外研究表明,人脐血含有比骨髓细胞更原始更早期的造血干细胞群。移植后所引起的GVHD发生率及程度都比骨髓及外周血要低,但其相应的GVL效应也较低,容易复发。单份脐血所含有的造血细胞量仅可以满足一定体重以下的儿童患者需求,对需移植的大部分成人患者则要进行体外扩增。脐血体外扩增后进行干细胞移植是一种新的设想和尝试,移植物中免疫细胞的组成和功能是决定干细胞移植能否成功重建造血与免疫、以及平衡GVHD和GVL的重要因素。为了研究脐血体外同时诱导扩增T、NK和CD34 细胞的可能性,本实验无菌采集健康正常足月产新生儿脐血,并分离出单个核细胞,在不同的细胞因子组合作用下用IMDM培养液培养14天。在培养0、3、7、14天时收集细胞,用FCM分析扩增前后脐血干/祖细胞及T、NK免疫细胞含量。结果表明,与无细胞因子的对照组相比,所有细胞因子SCF,IL3,IL6,IL7,IL2组合组别均能显著扩增脐血中的单个核细胞。所有细胞因子组合组别均能显著增加脐血中的CD34 细胞比例,使其含量从新鲜脐血中的1.6%升高到最高D组的11.9%。第7天时CD34 细胞平均增加10至50倍不等。新鲜脐血中CD3 T细胞平均为(18.7±4.3)%,在无细胞因子的对照组中CD3 T细胞下降明显,而在含细胞因子的组别中CD3 T有不同程度的增加,扩增最高的组别中CD3 T细胞是新鲜脐血的2倍。在新鲜脐血中含(3.6±1.9)?56 细胞。CD56 细胞数量仅在含细胞因子IL2的组别中有显著增加,其它组则无明显变化。结论:脐血中T细胞、NK细胞在一定细胞因子组合下,可与干/祖细胞同时在体外被扩增和诱导分化。

Ex vivo Expansion of T, NK and CD34 + Cells from Umbilical Cord Blood

Umbilical cord blood stem cell transplantation (CBSCT) has made significant progress in treatment of lethal congenital or malignant disorders. Both the incidence and severity of GVHD from CBSCT were lower than that from bone marrow and peripheral blood stem cell transplantation, particularly for adult patients, but these advantages were also associated with higher rates of relapse. The immune-mediated effect of natural killer and cytotoxic T cells against residual tumor cells were shown to prevent relapse and to induce remission after bone marrow transplantation. To explore possibility of ex vivo expansion of T, NK and CD34(+) cells from umbilical cord blood, cord blood was expanded ex vivo with different combinations of cytokines, T and NK cells proliferation and differentiation were observed. CB MNCs were separated in Ficoll-Isopaque column and cultured in IMDM for 14 days with different recombinant cytokines. Cultured cells were collected and analyzed for progenitor/stem cell immunophenotyping at day 0, 3, 7, and 14 by using flow cytometry. The results indicated that all test groups cultured with different combinations of SCF, IL-3, IL-6, IL-7, IL-2 showed significant expansion of UCB MNC, compared with the group without cytokines. All test groups showed expansion effects on CD34(+) cells, CD34(+) percentage went up from 1.6% in fresh CB to the highest 11.9% in group D (SCF + IL-3, IL-6, IL-2). The CD34(+) cells peak displayed at day 7 of culture in group A and D, while in other two groups B and C appeared at day 14 of culture. The expansion multiple of CD34(+) cells in all test groups at day 7 of culture were from 10 to 50. The average value of CD3(+) T cell in fresh UCB was 18.7 +/- 4.3%, the CD3(+) T cells decreased sharply in the medium without any interleukin, while obvious increase were observed in the other test groups containing different combinations of cytokines. The maximal expansion multiple of CD3(+) T cells reached 2 times of the fresh UCB level. CD56(+) cells amounted to 3.6 +/- 1.9% of fresh UCB, CD56(+) cell number increased significantly only in medium containing IL-2. It is concluded that T cells, NK cells as well as stem/progenitor cells can be expanded in the same time from CB-MNC with the combinations of cytokines.