STEM CELL GENE THERAPY USING LONG TERM BONE MARROW CULTURE TRANSDUCTION PROTOCOL

将基因导入造血干细胞（HSC）的尝试 总的来说，使用基于鼠逆转录病毒的 体外转染CD 34+细胞的载体导致低水平的 （0 1-1%）的基因标记在有限的时间内的研究 犬证明，用逆转录病毒载体转导的LTBMC 在体内提供了更高水平的基因标记。 这项技术是，通过使用未分级的骨髓， 预选;干细胞和逆转录病毒能够共定位在 基质;系统选择LTCIC;转导发生3次， 喂养后21天，使细胞处于周期中， 转导效率我们检测了这种技术在 恒河猴在2只接受这种自体移植的动物中， 移植过程中，没有实施预处理方案 将未分级的骨髓用PA 317 LN转导15 - 18天， 基于载体的动物监测“neo”标记基因在 外周血和骨髓中，我们观察到1%至3%的基因 在外周血中标记约3个月 neo在骨髓中的表达普遍低于外周血 这种技术似乎令人鼓舞，因为我们的数据与 其他人观察到的情况，但我们的协议是在没有 最近的努力集中在试图 使用编码GFP的逆转录病毒载体将LTBMC用于转染HSC 使用由R Howley提供的逆转录病毒载体的初始实验 导致无法维持LTBMC，这似乎是由于 由逆转录病毒生产细胞系提供的可溶性因子 结果表明，LTBMC技术可能难以 这些研究的结果可以推广到其他逆转录病毒载体， 在优化人类基因改造的努力中证明是有用的 造血干细胞

Attempts to introduce genes into hematopoietic stem cells (HSCs) have been disappointing In general, using murine retroviral based vectors to transduce CD34+ cells in vitro have resulted in a low level (0 1-1%) of gene marking for a limited period of time Studies in canines demonstrated that LTBMC transduced with retroviral vectors gave higher levels of gene marking in vivo The advantage of this technique is that by using unfractionated marrow there is no preselection; stem cells and retrovirus are able to colocalize on the stroma; the system selects for LTCIC; transduction occurs 3 times over 21 days following feeding so that cells are in cycle, improving transduction efficiency We examined the utility of this technique in rhesus macaques In 2 animals that underwent this autologous transplantation procedure, no conditioning regime was implemented Unfractionated marrow was transduced for 15 - 18 days with a PA317LN based vector Animals were monitored f or "neo" the marker gene in peripheral blood and bone marrow We observed between 1% and 3% gene marking in peripheral blood for approximately 3 months The frequency of neo in bone marrow was generally lower than that in peripheral blood This technique appears encouraging as our data are similar to what has been observed by others, but our protocol is in the absence of any conditioning regimen Recent efforts have focused on attempts to use LTBMC to transduce HSC using a retroviral vector encoding GFP Initial experiments using a retroviral vector provided by R Howley resulted in a failure to maintain LTBMC, which appears to be due to soluble factors provided by the retroviral producer cell line These results suggest that the LTBMC technique may be difficult to generalize to other retroviral vectors Results of these studies may prove useful in efforts to optimize genetic modification of human hematopoietic stem cells