Boswell H S, Wade P M, Quesenberry P J
J Immunol. 1984 Dec;133(6):2940-9.
Hematopoietic stem cells of high proliferative potential such as the giant macrophage colony-forming cell HPP-CFC, were present in the marrow of mice treated with high dose 5-fluorouracil (5Fu) (150 mg/kg i.v.), whereas most committed granulocyte-macrophage progenitors, GM-CFU-C, were depleted. Enrichment of primitive stem cells in post 5-Fu bone marrow (5FuBM) was reflected in an enhanced capacity to proliferate in suspension cultures stimulated by the mixture of lymphokines present in Con A spleen-conditioned medium supernatant (Con A CM) when compared to normal bone marrow. The population of blast-like cells harvested at 5 days from suspension cultures of 5FuBM with Con A CM showed marked increases in stem cells GM-CFU-C and HPP-CFC. For this reason, 5FuBM was utilized to study the cell surface characteristics of putative pluripotential stem cells capable of giving rise to committed stem cells in suspension cultures. Treatment of 5FuBM (BDF1 mice) before suspension culture with a high concentration of either of two cytotoxic monoclonal antibodies directed against the Thy-1.2 surface antigen in the presence of rabbit complement reduced or abrogated the generation of stem cells HPP-CFC and GM-CFU-C in suspension cultures, even though the input content of HPP-CFC and GM-CFU-C in treated 5FuBM compared with control 5FuBM showed little reduction by the antibody plus complement treatment. The Thy-1+ cell required for generation of stem cells was not a T cell, because reconstitution of Thy-1.2-depleted 5FuBM with spleen nylon nonadherent (T) cells did not reconstitute the generation of stem cells, even though T cells did grow in the suspension cultures. In addition, depletion from 5FuBM of cells expressing Lyt-1 and Lyt-2 antigens, unambiguous markers of T cell-thymocyte differentiation, did not ablate the generation of HPP-CFC and GM-CFU-C. Rather, performance of Thy-1 cell depletion at lower efficiency, which still abrogated T cell function, ablated generation of HPP-CFC but did not affect the generation of GM-CFU-C. It was concluded that 5FuBM contains distinct Thy-1+ primitive stem cells expressing different amounts of Thy-1 antigen correlating with their respective generation potentials. Some of these Thy-1+ progenitor cells may be pluripotential.
高增殖潜能的造血干细胞，如巨巨噬细胞集落形成细胞（HPP-CFC），存在于接受高剂量5-氟尿嘧啶（5Fu，150mg/kg静脉注射）治疗的小鼠骨髓中，而大多数定向粒细胞-巨噬细胞祖细胞（GM-CFU-C）则被耗尽。与正常骨髓相比，5-氟尿嘧啶处理后的骨髓（5FuBM）中原始干细胞的富集表现为在刀豆蛋白A脾条件培养基上清液（Con A CM）中存在的细胞因子混合物刺激下，悬浮培养中的增殖能力增强。从用Con A CM进行悬浮培养的5FuBM中于第5天收获的原始样细胞群体中，干细胞GM-CFU-C和HPP-CFC显著增加。因此，5FuBM被用于研究在悬浮培养中能够产生定向干细胞的假定多能干细胞的细胞表面特征。在用兔补体存在下，用两种针对Thy-1.2表面抗原的细胞毒性单克隆抗体中的高浓度之一对5FuBM（BDF1小鼠）进行悬浮培养前处理，可减少或消除悬浮培养中干细胞HPP-CFC和GM-CFU-C的产生（尽管与对照5FuBM相比，经抗体加补体处理的5FuBM中HPP-CFC和GM-CFU-C的输入含量几乎没有减少）。产生干细胞所需的Thy-1+细胞不是T细胞，因为用脾尼龙非黏附（T）细胞重建Thy-1.2耗尽的5FuBM并不能重建干细胞的产生，尽管T细胞确实在悬浮培养中生长。此外，从5FuBM中去除表达Lyt-1和Lyt-2抗原（T细胞-胸腺细胞分化的明确标志物）的细胞，并不会消除HPP-CFC和GM-CFU-C的产生。相反，以较低效率进行Thy-1细胞耗竭（这仍会消除T细胞功能），会消除HPP-CFC的产生，但不影响GM-CFU-C的产生。得出的结论是，5FuBM含有不同的Thy-1+原始干细胞，它们表达不同量的Thy-1抗原，与其各自的产生潜能相关。这些Thy-1+祖细胞中的一些可能是多能的。
