title: Purification of a membrane-derived human erythroid growth factor.
abstract: We have purified erythroid burst-promoting activity (BPA) from human lymphocyte plasma membranes by detergent extraction followed by gel-filtration, ion-exchange, and hydroxylapatite chromatography. BPA is a heat-stable integral membrane glycoprotein of Mr 28,000 by gel filtration whose activity is eluted from NaDodSO4/polyacrylamide gels as a broad band at Mr 25,000-29,000. The growth stimulator appears to be erythroid-specific, stimulating proliferation of the human erythroid burst-forming unit (BFU-E) by up to 600% of control values when tested in serum-free bone marrow culture. In contrast, it is devoid of granulocyte/macrophage colony-stimulating factor activity and has a negligible effect on the formation of human megakaryocyte and mixed hematopoietic colonies. Polyclonal anti-lymphocyte membrane IgG, which neutralizes BPA expression in culture, completely absorbs BPA from all lymphocyte-derived sources [solubilized lymphocyte plasma membranes, membrane-containing vesicles shed into lymphocyte conditioned medium (LCM) and soluble vesicle-free LCM supernatants], suggesting that soluble and membrane-derived lymphocyte BPA are antigenically related. This membrane glycoprotein may be an important mediator of proximal cellular interactions that are known to promote erythropoiesis in vitro.
authors.affiliation: Department of Medicine, St. Elizabeth's Hospital, Boston, MA 02135.
authors.forename: L
authors.initials: L
authors.lastname: Feldman
authors.forename: C M
authors.initials: CM
authors.lastname: Cohen
authors.forename: M A
authors.initials: MA
authors.lastname: Riordan
authors.forename: N
authors.initials: N
authors.lastname: Dainiak
mesh_terms: D002462:Cell Membrane / Q000276:immunology; D002845:Chromatography; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D017886:Durapatite; D006023:Glycoproteins / Q000302:isolation & purification*; D006412:Hematopoietic Stem Cells / Q000187:drug effects; D006801:Humans; D006882:Hydroxyapatites; D008214:Lymphocytes / Q000276:immunology*; D008222:Lymphokines / Q000302:isolation & purification* / Q000494:pharmacology; D008970:Molecular Weight; D019714:Tissue Inhibitor of Metalloproteinases
chemical_list: D006023:Glycoproteins; D006882:Hydroxyapatites; D008222:Lymphokines; D019714:Tissue Inhibitor of Metalloproteinases; D017886:Durapatite