title: Direct synergistic effects of interleukin-7 on in vitro myelopoiesis of human CD34+ bone marrow progenitors.
abstract: Interleukin-7 (IL-7) is an important growth factor in B and T lymphopoiesis in mouse and human, whereas IL-7 has been regarded to lack proliferative effects on cells within the myeloid lineage. However, we have recently reported that IL-7 potently can enhance colony stimulating factor (CSF)-induced myelopoiesis from primitive murine hematopoietic progenitors, showing a novel role of IL-7 in early murine myelopoiesis. Using CD34+ human hematopoietic progenitor cells, we show here a similar role of IL-7 in human myelopoiesis, although interesting differences between the two species were found as well. Although purified recombinant human (rh)IL-7 alone did not induce any proliferation of CD34+ cells, IL-7 in a concentration-dependent manner enhanced the colony formation induced by all four CSFs up to threefold. Furthermore, stem cell factor (SCF)-induced granulocyte-macrophage (GM) colony formation was increased fourfold in the presence of IL-7. Single-cell cloning assays showed that these synergistic effects of IL-7 were directly mediated on the targeted progenitors, and that IL-7 increased the number, as well as the size of the colonies formed. Morphological examination showed that IL-7 affected the progeny developed from CD34+ cells stimulated by G-CSF or IL-3, increasing the number of CFU-M (colony forming unit-macrophage) and CFU-granulocyte-macrophage, whereas the number of CFU-granulocyte were unaltered.
authors.affiliation: Department of Immunology, Norwegian Radium Hospital, Oslo.
authors.forename: F W
authors.initials: FW
authors.lastname: Jacobsen
authors.forename: L S
authors.initials: LS
authors.lastname: Rusten
authors.forename: S E
authors.initials: SE
authors.lastname: Jacobsen
mesh_terms: D001854:Bone Marrow Cells; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D003115:Colony-Stimulating Factors / Q000008:administration & dosage*; D004357:Drug Synergism; D006410:Hematopoiesis / Q000187:drug effects*; D016298:Hematopoietic Cell Growth Factors / Q000008:administration & dosage*; D006412:Hematopoietic Stem Cells / Q000187:drug effects*; D006801:Humans; D066298:In Vitro Techniques; D015851:Interleukin-7 / Q000008:administration & dosage*; D019089:Stem Cell Factor
chemical_list: D003115:Colony-Stimulating Factors; D016298:Hematopoietic Cell Growth Factors; D015851:Interleukin-7; D019089:Stem Cell Factor