Clarke B J, Axelrad A A, Shreeve M M, McLeod D L
Proc Natl Acad Sci U S A. 1975 Sep;72(9):3556-60. doi: 10.1073/pnas.72.9.3556.
Erythroid colonies could be produced without the addition of erythropeietin in plasma cultures seeded with bone marrow cells from normal C3Hf/Bi mice by exposure of the cells in vitro to medium from a cell line (IS) that continuously produces Friend leukemia virus in culture. The activity in the culture medium was viral rather than erythropoietin-like, since it was sedimentable by high-speed centrifugation and heat labile. Erythroid colonies did not develop when the bone marrow cells exposed to virus-containing medium were from mice genetically resistant to Friend virus. IS culture medium contained both Friend spleen focus-forming and XC-plaque-forming activities. No erythroid colonies were induced when genetically sensitive cells were exposed to a preparation from which the spleen focus-forming activity had been removed, but which contained XC plaque-forming activity in high concentration. Thus the spleen focus-forming component of Friend virus appeared to be responsible for inducing erythroid colony formation without erythropoietin in vitro. Some erythroid colonies were also found in control cultures to which neither virus nor erythropoietin had been added. Reduction in the concentration of fetal calf serum in the culture medium substantially decreased the number of these colonies but had only a minor effect on the number of virus-induced colonies. The number of erythroid colonies produced after 2 days of culture without erythropoietin or fetal calf serum was approximately proportional to the titer of Friend spleen focus-forming virus to whcih the bone marrow cells had been exposed. This system should prove useful for investigation in vitro of Friend virus--host cell interactions which lead to erythropoietin-independent erythropoiesis.
在用来自正常C3Hf/Bi小鼠的骨髓细胞接种的血浆培养物中，通过将细胞在体外暴露于来自一个细胞系（IS）的培养基中，可以在不添加促红细胞生成素的情况下产生红系集落。该细胞系在培养中持续产生弗氏白血病病毒。培养基中的活性是病毒性质的而非促红细胞生成素样的，因为它可通过高速离心沉淀且对热不稳定。当暴露于含病毒培养基的骨髓细胞来自对弗氏病毒具有遗传抗性的小鼠时，红系集落不会形成。IS培养基同时含有弗氏脾集落形成活性和XC蚀斑形成活性。当遗传敏感细胞暴露于一种已去除脾集落形成活性但含有高浓度XC蚀斑形成活性的制剂时，不会诱导出红系集落。因此，弗氏病毒的脾集落形成成分似乎是在体外不依赖促红细胞生成素诱导红系集落形成的原因。在未添加病毒或促红细胞生成素的对照培养物中也发现了一些红系集落。培养基中胎牛血清浓度的降低显著减少了这些集落的数量，但对病毒诱导的集落数量只有轻微影响。在不添加促红细胞生成素或胎牛血清的情况下培养2天后产生的红系集落数量大致与骨髓细胞所暴露的弗氏脾集落形成病毒的滴度成正比。该系统应被证明对体外研究导致不依赖促红细胞生成素的红细胞生成的弗氏病毒 - 宿主细胞相互作用有用。
