title: Transitional change of colony stimulating factor requirements for erythroid progenitors.
abstract: The course of the differentiation and proliferation of the human erythroid burst-forming units (BFU-E) to colony-forming units (CFU-E) was directly investigated using a combination of highly purified BFU-E, a liquid culture system, and the following clonal assay. Highly purified human blood BFU-E with a purity of 45-79% were cultured in liquid medium with recombinant human erythropoietin (rEP) and recombinant human interleukin-3 (rIL-3) to generate more differentiated erythroid progenitors. The cultured cells were collected daily for investigating the morphology, the increment in the number of cells and the clonality. Ninety percent of purified BFU-E required not only rEP but also rIL-3 for clonal development. By 7 days of liquid culture, the total cell number increased 237 +/- 20-fold above the starting cells, while erythroid progenitors increased 156 +/- 74-fold. As the incubation time in liquid culture increased, the cells continuously differentiated in morphology. Replating experiments with rEP combined with or without rIL-3 showed the following: 1) The number of erythroblasts that were part of erythroid colonies decreased with accompanying erythroid progenitor differentiation and proliferation. 2) As the incubation time in liquid culture increased, erythroid progenitors had a graded loss of their dependency on rIL-3 and a complete loss of dependency was observed after 3 days of liquid culture. At that time 85% of the erythroid progenitors gave rise to colonies of more than 100 erythroblasts which were equivalent to mature BFU-E. These studies provide a quantitative assessment of the loss of IL-3 dependency by BFU-E and indicate that the size of the generated erythroid colonies and their IL-3 requirement correlate with the erythroid differentiated state.
authors.affiliation: Second Department of Internal Medicine, Hokkaido University School of Medicine, Sapporo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sawada
authors.forename: S B
authors.initials: SB
authors.lastname: Krantz
authors.forename: C H
authors.initials: CH
authors.lastname: Dai
authors.forename: N
authors.initials: N
authors.lastname: Sato
authors.forename: M
authors.initials: M
authors.lastname: Ieko
authors.forename: S
authors.initials: S
authors.lastname: Sakurama
authors.forename: T
authors.initials: T
authors.lastname: Yasukouchi
authors.forename: S
authors.initials: S
authors.lastname: Nakagawa
mesh_terms: D000328:Adult; D002454:Cell Differentiation; D002469:Cell Separation; D002478:Cells, Cultured; D002999:Clone Cells; D004900:Erythroblasts / Q000166:cytology; D015672:Erythroid Precursor Cells / Q000166:cytology* / Q000187:drug effects; D004920:Erythropoiesis; D004921:Erythropoietin / Q000494:pharmacology*; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000494:pharmacology; D013997:Time Factors
chemical_list: D007377:Interleukin-3; D011994:Recombinant Proteins; D004921:Erythropoietin; D016179:Granulocyte Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor