title: Stem cell factor (c-kit ligand) enhances the interleukin-9-dependent proliferation of human CD34+ and CD34+CD33-DR- cells.
abstract: We have studied the effects of recombinant human interleukin-9 (IL-9), alone and combined with stem cell factor (SCF, c-kit ligand), IL-3, and granulocyte-macrophage colony-stimulating factor (GM-CSF) on the clonogenic proliferation of highly enriched human hematopoietic CD34+ and CD34+CD33-DR- progenitor cells. Colony assays were performed under serum-containing and serum-free conditions. IL-9, as a single agent, did not support colony formation. The addition of erythropoietin (Epo) to IL-9 induced the growth of erythroid progenitors (BFU-E) derived from both CD34+ and CD34+CD33-DR- cells. The IL-9-dependent growth of BFU-E derived from CD34+ cells was increased in an additive manner by SCF and, to a lesser extent, by IL-3, whereas CD34+CD33-DR- erythroid precursors were also responsive to GM-CSF in combination with IL-9. The addition of SCF to IL-9 did stimulate the development of CD34+ and CD34+CD33-DR- macroscopic, multicentered BFU-E and multilineage colonies (CFU-GEMM). When IL-9 was used in serum-free conditions, the growth of CD34+ and CD34+CD33-DR- BFU-E was observed in the presence of Epo. Moreover, a marked synergy on BFU-E colony formation was evident when IL-9 was combined with SCF, and their activity was enhanced by the addition of IL-3. IL-9 showed a negligible proliferative activity on colony-forming units-granulocyte/macrophage (CFU-GM). However, it increased the number of CD34+CD33-DR- CFU-GM responsive to IL-3 (37% of the colonies generated by phytohemagglutinin-stimulated lymphocyte conditioned medium [PHA-LCM]). The effects of IL-9 on CD34+CD33-DR- cells were also studied in a short-term suspension culture system, which evaluates the proliferation of progenitors earlier than day 14 CFU-C (Delta assay). In this system, IL-9 had a minimal activity on its own. In combination with SCF, however, it induced a nine-fold expansion of CD34+CD33-DR- cells, which generated a greater number of CFU-GM than BFU-E in secondary methylcellulose cultures. These experiments indicate that IL-9 induces the proliferation of very primitive human erythroid cells, and this effect is potentiated by SCF and other cytokines. Furthermore, IL-9 synergizes in vitro with the c-kit ligand in expanding the pool of early pluripotent hematopoietic progenitor cells.
authors.affiliation: Istituto di Ematologia Seràgnoli, Università di Bologna, Italy.
authors.forename: R M
authors.initials: RM
authors.lastname: Lemoli
authors.forename: A
authors.initials: A
authors.lastname: Fortuna
authors.forename: M
authors.initials: M
authors.lastname: Fogli
authors.forename: M R
authors.initials: MR
authors.lastname: Motta
authors.forename: S
authors.initials: S
authors.lastname: Rizzi
authors.forename: C
authors.initials: C
authors.lastname: Benini
authors.forename: S
authors.initials: S
authors.lastname: Tura
mesh_terms: D015703:Antigens, CD / Q000032:analysis* / Q000276:immunology; D018952:Antigens, CD34; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis* / Q000276:immunology; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D004357:Drug Synergism; D015672:Erythroid Precursor Cells / Q000166:cytology / Q000187:drug effects; D004921:Erythropoietin / Q000494:pharmacology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006684:HLA-DR Antigens / Q000032:analysis* / Q000276:immunology; D006410:Hematopoiesis / Q000187:drug effects / Q000502:physiology; D016298:Hematopoietic Cell Growth Factors / Q000494:pharmacology*; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000276:immunology*; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D016906:Interleukin-9 / Q000494:pharmacology*; D063268:Sialic Acid Binding Ig-like Lectin 3; D019089:Stem Cell Factor
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D015214:Antigens, Differentiation, Myelomonocytic; C571163:CD33 protein, human; D016895:Culture Media, Serum-Free; D006684:HLA-DR Antigens; D016298:Hematopoietic Cell Growth Factors; D007377:Interleukin-3; D016906:Interleukin-9; D063268:Sialic Acid Binding Ig-like Lectin 3; D019089:Stem Cell Factor; D004921:Erythropoietin; D016178:Granulocyte-Macrophage Colony-Stimulating Factor