title: The mast cell-committed progenitor. I. Description of a cell capable of IL-3-independent proliferation and differentiation without contact with fibroblasts.
abstract: We have identified a late, committed stage in the differentiation of the mast cell progenitor just before granulation. Mast cell committed progenitors (MCCP) are nongranulated cells with a density of 1.060 to 1.070 g/ml which can be harvested from the mesenteric lymph node of mice infected with Nippostrongylus brasiliensis. Mast cell-committed progenitors are able to proliferate and differentiate in the absence of IL-3 or IL-4 when cultured on a monolayer of embryonic skin or 3T3 fibroblasts and can form colonies in methylcellulose supplemented with fibroblast conditioned medium. Fibroblast conditioned medium appears to contain a soluble MCCP proliferation factor that maintains biologic activity when heated to 56 degrees C for 45 min but is destroyed by incubation with either trypsin or chymotrypsin. It can be selectively precipitated with 60 to 70% saturated ammonium sulfate. The factor is not absorbed by immobilized antibodies to nerve growth factor. The MCCP proliferation activity of the factor could not be mimicked by IL-1, IL-2, IL-4, granulocyte-macrophage-CSF, granulocyte-CSF, macrophage-CSF, IFN-alpha/beta, IFN-gamma, nerve growth factor, epidermal growth factor, serum fibronectin, heparin, or a number of glycosaminoglycans. At high salt concentrations, the factor passes through a 50-kDa membrane and can be concentrated above a 5-kDa membrane. MCCP acquire a connective tissue phenotype when cultured on a fibroblast monolayer and a mucosal phenotype when cloned in the presence of conditioned medium from PWM-stimulated spleen cells. When cultured in the absence of IL-3 on a monolayer of embryonic skin or 3T3 fibroblasts, mast cell-committed progenitors produce mast cells which stain with berberine sulfate suggesting a connective tissue phenotype; however, the mast cells that develop when mast cell-committed progenitors are cultured in the presence of IL-3 or conditioned media from PWM-stimulated spleen cells do not stain with berberine sulfate. MCCP intercalate into monolayers of embryonic skin or 3T3 fibroblasts, but T cells are not able to associate with the monolayer and can be completely washed away. Attempts to enrich mast cell-committed progenitors by intercalation and elution from embryonic skin monolayers proved unsuccessful, but some enrichment of mast cell-committed progenitors could be achieved by discontinuous Percoll gradients. Thus, we have identified a way to obtain late-stage, mast cell-committed progenitors in an environment that is virtually uncontaminated with other hematopoietic progenitors.
authors: Department of Microbiology and Immunology, Medical College of Virginia, Richmond, 23298.
authors: D L
authors: DL
authors: Jarboe
authors: J S
authors: JS
authors: Marshall
authors: T R
authors: TR
authors: Randolph
authors: A
authors: A
authors: Kukolja
authors: T F
authors: TF
authors: Huff
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000502:physiology; D002450:Cell Communication / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002469:Cell Separation; D002499:Centrifugation, Density Gradient; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003470:Culture Media; D003594:Cytoplasmic Granules / Q000032:analysis; D004622:Embryo, Mammalian; D005260:Female; D005347:Fibroblasts / Q000502:physiology*; D006025:Glycosaminoglycans / Q000494:pharmacology; D006133:Growth Substances / Q000502:physiology; D006493:Heparin / Q000494:pharmacology; D007377:Interleukin-3; D008407:Mast Cells / Q000032:analysis / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D012879:Skin Physiological Phenomena; D013234:Stem Cells / Q000032:analysis / Q000502:physiology*; D013601:T-Lymphocytes
chemical_list: D003470:Culture Media; D006025:Glycosaminoglycans; D006133:Growth Substances; D007377:Interleukin-3; D006493:Heparin