Evidence for direct action of human biosynthetic (recombinant) GM-CSF on erythroid progenitors in serum-free culture.
The biologic activity of human biosynthetic granulocyte-monocyte colony stimulating factor (GM-CSF) was investigated in serum-free culture of erythroid progenitors derived from adult peripheral blood. The morphology of erythroid bursts and the cloning efficiency of BFU-E under serum-free conditions were similar to those observed in dishes with fetal bovine serum (FBS). For these experiments, progenitor cells were partially purified by Ficoll-Paque density centrifugation, adherence to a plastic surface, and complement-mediated cytotoxicity of Leu-1+ elements. For some studies, blastlike cells were harvested directly from 6-day-old semisolid cultures. In serum-free culture of the light-density cell fraction, biosynthetic erythropoietin (Ep) was sufficient for formation of pure and mixed erythroid colonies whereas GM-CSF was required for granulocyte-monocytic colonies. When adherent and Leu-1+ cells were removed, or when in vitro differentiated blast cells were used as a source of progenitors, neither Ep or GM-CSF alone induced colony formation. In dishes supplemented with both growth factors, erythroid bursts were detected. Although the presence of GM-CSF alone did not induce formation of any colony or clusters, BFU-E were recorded when Ep was added 8 days later, suggesting that BFU-E could be maintained. Terminal maturation of the resulting erythroid bursts was delayed by 8 days. These results provide evidence that GM-CSF acts directly on early erythroid progenitors. Furthermore, they suggest that both Ep and GM-CSF are necessary to start the differentiation process.
Migliaccio
A R
AR
Department of Hematology, Istituto Superiore Sanita', Rome.
Bruno
M
M
Migliaccio
G
G
D000328:Adult; D001773:Blood Cells / Q000166:cytology; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D003115:Colony-Stimulating Factors / Q000494:pharmacology*; D003470:Culture Media; D004920:Erythropoiesis / Q000187:drug effects*; D004921:Erythropoietin / Q000494:pharmacology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D006133:Growth Substances / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D011994:Recombinant Proteins / Q000494:pharmacology*
D003115:Colony-Stimulating Factors; D003470:Culture Media; D006133:Growth Substances; D011994:Recombinant Proteins; D004921:Erythropoietin; D016178:Granulocyte-Macrophage Colony-Stimulating Factor