Xu Zhixiang, Xu Ying, Zhu Jiankun, Shi Qin, Li Ying, Zhang Xueguang
Department of Immunology, Medical Biotechnology Institute, Suzhou Medical College, Suzhou 215007, China.
Chin Med J (Engl). 2002 Feb;115(2):202-5.
To investigate the direct effects of the Flt3 ligand (FL) on hematopoiesis, such as the stimulation of the formation of hematopoietic colonies and the proliferation of dendritic cells, as well as the indirect stimulation of hematopoiesis, especially via the proliferation of endothelial cells.
Mononuclear cells from human cord blood were plated in methylcellulose medium containing different cytokines to induce hematopoietic colony formation. Dendritic cells (DCs) were induced from the mononuclear cells with a cytokine cocktail with or without recombinant human soluble FL (rhFL; 100 ng/ml). The Flt3 receptors on the surface of a human microvascular endothelial cell line (ECV) were analyzed by flow cytometry. The proliferation of ECV stimulated by rhFL was measured with the microculture tetrazolium assay. The levels of FL, IL-6, IL-8, G-CSF and GM-CSF in the supernatant of ECV cultures were measured by enzyme linked immunoabsorbent assay (ELISA).
rhFL stimulates colony formation from cord blood when used as a sole stimulant. FL in combination with other cytokines increased colony formation significantly. The number of DCs was approximately 2.5 times higher when rhFL was used. rhFL stimulates the proliferation of ECV on which Flt3 receptors are expressed. Furthermore, ECV secretes FL, IL-6, IL-8, G-CSF and GM-CSF, which were augmented by tumor necrosis factor-alpha and rhFL.
rhFL enhances hematopoietic colony formation and DC proliferation from human cord blood cells. FL not only stimulates the proliferation of ECV, but is also secreted by ECV. FL may exert direct and indirect effects on hematopoiesis.
研究Flt3配体（FL）对造血的直接作用，如刺激造血集落形成和树突状细胞增殖，以及对造血的间接刺激作用，尤其是通过内皮细胞增殖实现的间接刺激作用。
将人脐带血单个核细胞接种于含不同细胞因子的甲基纤维素培养基中，诱导造血集落形成。用含或不含重组人可溶性FL（rhFL；100 ng/ml）的细胞因子混合物从单个核细胞诱导树突状细胞（DC）。通过流式细胞术分析人微血管内皮细胞系（ECV）表面的Flt3受体。用微量培养四氮唑法检测rhFL刺激的ECV增殖。用酶联免疫吸附测定（ELISA）法检测ECV培养上清液中FL、IL-6、IL-8、G-CSF和GM-CSF的水平。
rhFL单独用作刺激剂时可刺激脐带血形成集落。FL与其他细胞因子联合使用可显著增加集落形成。使用rhFL时，DC数量约高出2.5倍。rhFL刺激表达Flt3受体的ECV增殖。此外，ECV分泌FL、IL-6、IL-8、G-CSF和GM-CSF，肿瘤坏死因子-α和rhFL可增加其分泌。
rhFL可增强人脐带血细胞的造血集落形成和DC增殖。FL不仅刺激ECV增殖，而且由ECV分泌。FL可能对造血发挥直接和间接作用。
