title: Modest stimulatory effect of recombinant human GM-CSF on colony growth from peripheral blood human megakaryocyte progenitor cells.
abstract: Recombinant human granulocyte-macrophage colony-stimulating factor (rGM-CSF) has been previously demonstrated to stimulate colony formation from human myeloid, erythroid, and multipotential stem cells. In this investigation, we evaluated the effects of rGM-CSF on colony growth by human megakaryocyte progenitors (CFU-Meg). rGM-CSF was tested at concentrations of 0.1-100 U/ml in plasma clot cultures of adherent-depleted normal peripheral blood mononuclear cells. Control cultures were concurrently prepared containing either no stimulator or megakaryocyte colony-stimulating factor (Meg-CSF) partially purified from aplastic canine serum. rGM-CSF increased megakaryocyte colony numbers from a baseline of 4.3 +/- 1.4 (+/- SEM) in the unstimulated cultures to a maximum of 21.0 +/- 5.3 colonies at an rGM-CSF concentration of 1.0 U/ml. Corresponding megakaryocytic colony size increased from 4.4 to 8.3 cells/colony. Further increasing the rGM-CSF concentration resulted in decreasing megakaryocyte colony growth, reaching 6.8 +/- 2.9 colonies at 100 U/ml. The maximum number of megakaryocyte colonies stimulated by rGM-CSF was only 23.3% of that achieved in the control cultures containing optimal concentrations of serum-derived Meg-CSF protein (2.0 mg/ml). Megakaryocyte colonies stimulated by rGM-CSF consisted of predominantly low ploidy cells approximately equally distributed in 2N, 4N, and 8N ploidy classes. There was no increase in ploidy with any rGM-CSF concentration. These data indicate that rGM-CSF has modest activity in stimulating human megakaryocyte colony growth that is substantially less than that present in serum-derived Meg-CSF. rGM-CSF appears to primarily affect the early mitotic phase of megakaryocyte colony development with little influence on megakaryocyte endoreduplication.
authors.affiliation: Department of Medicine, Miriam Hospital, Providence, RI 02906.
authors.forename: E M
authors.initials: EM
authors.lastname: Mazur
authors.forename: J L
authors.initials: JL
authors.lastname: Cohen
authors.forename: G G
authors.initials: GG
authors.lastname: Wong
authors.forename: S C
authors.initials: SC
authors.lastname: Clark
mesh_terms: D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003115:Colony-Stimulating Factors / Q000502:physiology*; D004247:DNA / Q000097:blood; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D006133:Growth Substances / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects; D006801:Humans; D007700:Kinetics; D008533:Megakaryocytes / Q000166:cytology* / Q000187:drug effects; D011994:Recombinant Proteins / Q000494:pharmacology*
chemical_list: D003115:Colony-Stimulating Factors; D006133:Growth Substances; D011994:Recombinant Proteins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D004247:DNA