title: Factors influencing release of granulocyte-macrophage colony-stimulating activity from human mononuclear phagocytes.
abstract: Mononuclear phagocytes play an important role in the regulation of hematopoiesis, not only by producing regulatory monokines such as prostaglandins, tumor necrosis factor and interleukin-1 (IL-1), but also by the production of colony-stimulating activity (CSA). Previously, we have demonstrated that granulocyte-macrophage CSA (GM-CSA) production by mononuclear phagocytes can be induced by IL-1. In the present study, the influence of culture conditions on the production of GM-CSA was studied. It was found that both human sera and fetal bovine sera contain constituents - at present undefined - that induce GM-CSA production. These factors are distinct from IL-1 and lipopolysaccharide. In selected experiments, no GM-CSA-inducing effect of serum was found, suggesting that the effect may be donor-related. GM-CSA release in the presence of serum could be reduced by 40% after incubation of mononuclear phagocytes at low cell concentrations in methylcellulose, indicating that intimate cell-cell contact is an additional factor that enhances GM-CSA release.
authors.affiliation: Department of Hematology, University Medical Center, Leiden, The Netherlands.
authors.forename: W E
authors.initials: WE
authors.lastname: Fibbe
authors.forename: P M
authors.initials: PM
authors.lastname: Kluck
authors.forename: N
authors.initials: N
authors.lastname: Duinkerken
authors.forename: P J
authors.initials: PJ
authors.lastname: Voogt
authors.forename: R
authors.initials: R
authors.lastname: Willemze
authors.forename: J H
authors.initials: JH
authors.lastname: Falkenburg
mesh_terms: D000818:Animals; D001790:Blood Physiological Phenomena; D002417:Cattle; D002478:Cells, Cultured; D003115:Colony-Stimulating Factors / Q000378:metabolism*; D003470:Culture Media / Q000494:pharmacology*; D006098:Granulocytes; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000378:metabolism*; D008264:Macrophages; D012636:Secretory Rate / Q000187:drug effects
chemical_list: D003115:Colony-Stimulating Factors; D003470:Culture Media