Bruno E, Briddell R A, Cooper R J, Brandt J E, Hoffman R
Division of Hematology/Oncology, Indiana University School of Medicine, Indianapolis 46202-5121.
Exp Hematol. 1992 May;20(4):494-9.
An evaluation of the effectiveness of a genetically engineered recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF)/interleukin 3 (IL-3) fusion protein (FP) as a means of delivering cytokine combinations to megakaryocyte (MK) progenitor cells was performed, utilizing a serum-depleted clonal assay system and a long-term bone marrow culture system. The effects of the FP, alone and in combination with a variety of other cytokines, on the primitive MK progenitor cell, the megakaryocyte burst-forming unit (BFU-MK), and the more differentiated megakaryocyte colony-forming unit (CFU-MK) were assessed. Subpopulations of bone marrow cells (CD34+ DR- for BFU-MK and CD34+ DR+ for CFU-MK) served as sources of these two classes of MK progenitor cells. The FP was equivalent to a combination of optimal concentrations of GM-CSF and IL-3 in promoting both the number and size of BFU-MK-derived colonies. The GM-CSF/IL-3 combination, however, promoted the formation of far greater CFU-MK-derived colonies than did the FP alone. The size of MK colonies formed in the presence of the FP or GM-CSF/IL-3 was similar. The ability of the FP to stimulate BFU-MK- but not CFU-MK-derived colony formation was also further augmented by the addition of interleukin 1 alpha (IL-1 alpha). The addition of c-kit ligand (KL) increased both FP-stimulated CFU-MK- and BFU-MK-derived colony numbers but only BFU-MK-derived colony size. In addition, the FP alone sustained long-term megakaryocytopoiesis in vitro to a level equivalent to that of the GM-CSF/IL-3 combination and was superior in this regard to either GM-CSF or IL-3 alone. These data indicate that FP is capable of supporting various stages of human megakaryocytopoiesis. We conclude that such genetically engineered molecules as the FP may prove to be effective means of pharmacologically delivering the biological effects of specific cytokine combinations.
利用血清缺乏克隆测定系统和长期骨髓培养系统，对基因工程重组粒细胞 - 巨噬细胞集落刺激因子（GM - CSF）/白细胞介素3（IL - 3）融合蛋白（FP）作为向巨核细胞（MK）祖细胞递送细胞因子组合的一种手段的有效性进行了评估。评估了FP单独以及与多种其他细胞因子联合使用时，对原始MK祖细胞、巨核细胞爆式集落形成单位（BFU - MK）和分化程度更高的巨核细胞集落形成单位（CFU - MK）的影响。骨髓细胞亚群（BFU - MK的CD34 + DR - 和CFU - MK的CD34 + DR +）作为这两类MK祖细胞的来源。在促进BFU - MK衍生集落的数量和大小方面，FP等同于最佳浓度的GM - CSF和IL - 3的组合。然而，GM - CSF/IL - 3组合促进形成的CFU - MK衍生集落比单独的FP多得多。在FP或GM - CSF/IL - 3存在下形成的MK集落大小相似。添加白细胞介素1α（IL - 1α）也进一步增强了FP刺激BFU - MK而非CFU - MK衍生集落形成的能力。添加c - kit配体（KL）增加了FP刺激的CFU - MK和BFU - MK衍生集落的数量，但仅增加了BFU - MK衍生集落的大小。此外，单独的FP在体外维持长期巨核细胞生成的水平与GM - CSF/IL - 3组合相当，在这方面优于单独的GM - CSF或IL - 3。这些数据表明FP能够支持人类巨核细胞生成的各个阶段。我们得出结论，诸如FP这样的基因工程分子可能被证明是药理学上递送特定细胞因子组合生物学效应的有效手段。
