Ex Vivo Culture of Umbilical Cord Blood Stem Cells for Adult Transplantation

描述(由申请人提供)：这项提案的总体目标是描述体外无血清培养条件，以扩大来自深低温保存的脐带血细胞的CD34+细胞，使其达到支持其在成人移植环境中使用的水平。脐带血用于成人移植的缺点被归因于脐带血中的长期移植细胞/造血干细胞太少。本文提出的研究表明，这个问题可以基于以下几个方面来避免：1)临床级无血清培养液的开发专门用于脐带血CD34+细胞的体外扩增，2)深低温保存的脐带血中的CD34+细胞成功地扩增到足以支持成人移植的水平，使用含有早期作用的细胞因子、Flt-3配体、干细胞因子、血小板生成素和白介素6的临床级无血清培养液，以及3)这些体外培养的CD34+细胞能够长期移植到人造血的胎羊模型中。第一阶段的里程碑将是重复和扩展这些初步研究，评估这些培养的CD34+细胞在越来越多的动物身上的长期移植能力，并评估更长的培养周期。这些关键结果将构成第二阶段提案的基础，以确定1)长期移植细胞在这些体外无血清培养条件下是否得到扩大或保持，2)确定产生高质量长期移植细胞的最佳培养周期，以及3)结合上述细胞因子平台评估其他细胞因子。在成人移植环境中，扩大长期移植细胞的能力将是无价的。这项建议的努力将为成人移植使用冷冻保存的脐带血的最佳条件提供临床相关数据。。根据这一建议衍生的产品将支持从深低温保存的脐带血中提取的CD34+细胞的体外培养，并维持这些细胞长期植入的能力。由于脐带血的长期移植细胞/造血干细胞很少，因此只能用于婴儿移植，不能用于成人移植。开发一种无血清的临床分级培养系统以支持长期移植细胞的扩张的能力将促进这些细胞在成人移植中的临床应用。

DESCRIPTION (provided by applicant): The overall goal of this proposal is to delineate the ex vivo serum-free culture conditions to expand CD34+ cells derived from cryopreserved umbilical cord blood cells to levels that will support its use in the adult transplant setting. The disadvantage of umbilical cord blood for adult transplants has been attributed to having too few long-term engrafting cells/hematopoietic stem cells in the cord blood. Studies presented herein suggest that this problem can be circumvented based on 1) the development of a clinical grade serum-free medium designated especially for the ex vivo expansion of CD 34+ cells derived from cord blood, 2) the successful expansion of CD 34+ cells from cryopreserved umbilical cord blood to levels adequate to support adult transplantation using the clinical grade serum-free medium with the early acting cytokines, Flt-3 ligand, stem cell factor, thrombopoietin, and Interleukin 6, and 3) the ability of these ex vivo cultured CD 34+ cells to engraft long-term in the fetal sheep model for human hematopoiesis. The Phase I milestone will be to repeat and extended these initial studies and assess the long-term engrafting ability of these cultured CD 34+ cells in increased numbers of animals and evaluate longer culture periods. These critical results will form the basis of the Phase II proposal to determine if 1) the long-term engrafting cells are being expanded or maintained under these ex vivo serum-free culture conditions, 2) define the optimal culture period yielding high quality long-term engrafting cells, and 3) evaluate other cytokines in combination with the above cytokine platform. The ability to expand the long-term engrafting cells would be invaluable in the adult transplant setting. The efforts from this proposal will yield clinically relevant data on the optimal conditions necessary for use of cryopreserved cord blood for adult transplantation. . The products derived form this proposal will support the ex vivo culture of CD34+ cells derived from cryopreserved umbilical cord blood and the maintenance of these cells ability to engraft long-term. Since cord blood has few long-term engrafting cells /hematopoietic stem cells it can only be used for infant transplantation, not adult transplantation. The ability to develop a serum-free clinical grade culture system that will support the expansion of the long-term engrafting cells will facilitate the clinical use of these cells in adult transplants.