Knaän-Shanzer S, Valerio D, van Beusechem V W
Department of Medical Biochemistry, University of Leiden, The Netherlands.
Gene Ther. 1996 Apr;3(4):323-33.
A multi-parameter fluorometric analysis was applied to study in vitro proliferation and expansion of a candidate hemopoietic stem cell population, ie CD34brightLin cells. In primary hemopoietic cell samples the CD34brightLin population comprised on average, 1% of CD34+ cells from bone marrow (BM) or umbilical cord blood and 0.1% of mobilized peripheral blood CD34+ cells. The fraction of CD34brightLin cells engaged in the S+G2/M phases of the cell cycle was largest in regenerating BM (10.6% versus 1-2% in the other sources). Maintenance of CD34+ BM cells in hemopoietic growth factor supplemented liquid cultures resulted in a decrease of the CD34brightLin population in most samples. Cell cycle analysis showed the constant existence of proliferating CD34+ cells during the culture period. The fraction of cycling CD34brightLin cells was, however, very small and only occasionally exceeded input values. At all tested time-points during culture, BM CD34+ cells could be transduced by a single incubation with a recombinant retrovirus supernatant. CD34brightLin cells, however, were much more refractory to retroviral vector-mediated transduction. This could be explained only in part by quiescence of CD34brightLin cells. Hence, factors other than cell proliferation clearly influence the early stages of retroviral transduction of human hemopoietic stem cells.
应用多参数荧光分析来研究候选造血干细胞群体即CD34brightLin细胞的体外增殖和扩增。在原发性造血细胞样本中，CD34brightLin群体平均占骨髓（BM）或脐带血中CD34+细胞的1%，以及动员外周血CD34+细胞的0.1%。处于细胞周期S+G2/M期的CD34brightLin细胞比例在再生骨髓中最大（10.6%，而其他来源为1%-2%）。在补充造血生长因子的液体培养物中维持CD34+ BM细胞，导致大多数样本中CD34brightLin群体减少。细胞周期分析显示在培养期间增殖性CD34+细胞持续存在。然而，处于细胞周期的CD34brightLin细胞比例非常小，仅偶尔超过输入值。在培养期间的所有测试时间点，BM CD34+细胞通过与重组逆转录病毒上清液单次孵育即可被转导。然而，CD34brightLin细胞对逆转录病毒载体介导的转导更具抗性。这只能部分地通过CD34brightLin细胞的静止来解释。因此，除细胞增殖外的其他因素显然会影响人类造血干细胞逆转录病毒转导的早期阶段。
