Okada S, Nakauchi H, Nagayoshi K, Nakamura M, Miura Y, Suda T
Department of Medicine, Jichi Medical School, Tochigi-ken, Japan.
Exp Hematol. 1992 Jun;20(5):546-51.
It has been reported that interleukin 6 (IL-6) acts on hemopoietic stem cells in synergism with interleukin 3 (IL-3), but it has not yet been clarified whether IL-6 acts directly on the stem cells or not. To investigate the mechanism of the synergism between IL-3 and IL-6, we sorted hemopoietic stem cells from untreated murine bone marrow cells using a two-laser fluorescence-activated cell sorter (FACS). Cells negative for the lymphohemopoietic lineage (lineage-negative, Lin-), with a high affinity to wheat germ agglutinin (WGA+), and showing a low expression of Thy-1 antigen (Thy-1low) were sorted and analyzed by in vitro and in vivo colony formation. This fraction was 0.4% of the total mononuclear bone marrow cells. Approximately 25% of these Lin-WGA+Thy-1low cells showed in vitro colony formation, whereas approximately 1% of them formed day-8 and day-12 spleen colonies. Thus, it appears that the Lin-WGA+Thy-1low cells were a highly enriched stem cell population. By FACS clone sorting, single cells were isolated from the enriched stem cell fraction and cultured in semisolid or liquid culture systems. Addition of IL-6 to methylcellulose medium containing IL-3 did not significantly increase the number of colonies. It is thus suggested that the target cells of IL-3 and IL-6 are the same as those of IL-3. The secondary colony-forming ability of primary colonies that developed in the presence of IL-6 and IL-3 was higher than that of colonies formed in the presence of IL-3 alone. In correspondence with this finding, the numbers of myeloid colonies and spleen colony-forming units (CFU-S) were increased by the incubation of these sorted cells for 7 days with IL-6 and IL-3 when compared with the effect of IL-3 alone. Therefore, it is concluded that IL-6 acts directly on hemopoietic stem cells to enhance their proliferation.
据报道，白细胞介素6（IL-6）与白细胞介素3（IL-3）协同作用于造血干细胞，但IL-6是否直接作用于干细胞尚未阐明。为了研究IL-3与IL-6协同作用的机制，我们使用双激光荧光激活细胞分选仪（FACS）从未经处理的小鼠骨髓细胞中分离造血干细胞。对淋巴造血谱系呈阴性（谱系阴性，Lin-）、对小麦胚凝集素具有高亲和力（WGA+）且Thy-1抗原表达低（Thy-1low）的细胞进行分选，并通过体外和体内集落形成进行分析。该部分占骨髓单个核细胞总数的0.4%。这些Lin-WGA+Thy-1low细胞中约25%表现出体外集落形成，而其中约1%形成第8天和第12天的脾集落。因此，Lin-WGA+Thy-1low细胞似乎是高度富集的干细胞群体。通过FACS克隆分选，从富集的干细胞部分分离出单个细胞，并在半固体或液体培养系统中培养。在含有IL-3的甲基纤维素培养基中添加IL-6并没有显著增加集落数量。因此，提示IL-3和IL-6的靶细胞与IL-3的靶细胞相同。在IL-6和IL-3存在下形成的原代集落的二次集落形成能力高于仅在IL-3存在下形成的集落。与此发现一致，与单独使用IL-3的效果相比，这些分选细胞与IL-6和IL-3一起孵育7天后，髓系集落和脾集落形成单位（CFU-S）的数量增加。因此，得出结论，IL-6直接作用于造血干细胞以增强其增殖。
