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为深入研究造血干细胞（ＨＳＣ）的生物学功能，根据表面标志，采用流式细胞仪分离和富集了小鼠骨髓中两类不同特征的ＨＳＣ亚群ｃ－ｋｉｔ＋Ｓｃａ－１＋和ｃ－ｋｉｔ＋Ｓｃａ－１－细胞。体外集落培养表明ｃ－ｋｉｔ＋Ｓｃａ－１＋细胞对ＩＬ－３或ＧＭ－ＣＳＦ单独刺激无反应，而ｃ－ｋｉｔ＋Ｓｃａ－１－细胞则可形成大小不等的细胞集落。多种造血生长因子［ＩＬ－３＋ＩＬ－６＋ＧＭ－ＣＳＦ＋Ｇ－ＣＳＦ＋Ｅｐｏ＋干细胞生长因子（ＳＣＦ）］联合可诱导ｃ－ｋｉｔ＋Ｓｃａ－１＋细胞形成大的细胞集落，但在培养１２天时尚无ＢＦＵ－Ｅ和粒、单核、红和巨核系细胞集落（ＣＦＵ－ＧＥＭＭ）形成；而同样条件下，ｃ－ｋｉｔ＋Ｓｃａ－１－细胞可形成ＢＦＵ－Ｅ和ＣＦＵ－ＧＥＭＭ以及其它各类集落。体内实验表明ｃ－ｋｉｔ＋Ｓｃａ－１＋细胞在培养８天时无脾集落（ＣＦＵ－Ｓ）形成，与ｃ－ｋｉｔ＋Ｓｃａ－１－细胞显著不同（Ｐ＜０．０１）。相反，ｃ－ｋｉｔ＋Ｓｃａ－１＋细胞包含了骨髓造血重建活性细胞，而ｃ－ｋｉｔ＋Ｓｃａ－１－细胞则缺乏。结果提示ｃ－ｋｉｔ＋Ｓｃａ－１＋细胞为早期的具重建长期造血功能的干细胞，而ｃ－ｋｉｔ＋Ｓｃａ－１－细胞则为相对分化后期的造血祖细胞。
To further study the biological functions of HSCs, two types of HSC subsets, c-kit + Sca-1 + and c-kit + Sca-1, were isolated and enriched by flow cytometry in mouse bone marrow -cell. In vitro colony culture showed that c-kit + Sca-1 + cells did not respond to stimulation with IL-3 or GM-CSF alone, whereas c-kit + Sca-1- cells formed colonies of varying sizes. A number of hematopoietic growth factors (IL-3 + IL-6 + GM-CSF + G-CSF + Epo + Stem Cell Growth Factor (SCF)) combined to induce large cell colonies of c-kit + Sca-1 + cells but no BFU- The mononuclear, erythroid and megakaryocyte colony formation (CFU-GEMM) formed; while under the same conditions, c-kit + Sca-1 cells formed BFU-E and CFU-GEMM as well as other types of colonies. In vivo experiments showed that c-kit + Sca-1 + cells did not form spleen colonies (CFU-S) when cultured for 8 days, which was significantly different from that of c-kit + Sca-1 cells (P <0.01). In contrast, c-kit + Sca-1 + cells contained myeloid hematopoietic reconstitution cells, whereas c-kit + Sca-1- cells were deficient. The results suggest that c-kit + Sca-1 + cells are early stem cells that reconstitute long-term hematopoiesis, whereas c-kit + Sca-1- cells are relatively late-stage hematopoietic progenitor cells.