title: Pluripotential hematopoietic stem cells in post-5-fluorouracil murine bone marrow express the Thy-1 antigen.
abstract: Expression of the Thy-1 alloantigen by hematopoietic stem and progenitor cells in post-5-fluorouracil (5-FU) murine bone marrow was investigated. FACS analysis of BDF1 bone marrow stained for Thy-1.2 with a triple-layer amplified labeling technique demonstrated that 35% of the total bone marrow population expressed Thy-1.2 (Thy-1.2+). Two distinct size subpopulations were observed in post-5-FU BDF1 marrow. Thy-1.2+ cells were present in both the large and the small subpopulations. FACS-separated bone marrow cells were also plated in methylcellulose cultures. Ninety percent of all colony-forming cells surviving in vivo administration of 5-FU were Thy-1.2+. Replating of primary hemopoietic colonies and morphologic examination of primary and secondary colonies demonstrated that the most primitive stem cells including "stem" (S) cells were Thy-1.2+. These cells (Thy-1.2+) were capable of self-renewal in vitro and exhibited multiple differentiation potentials in comparison to Thy-1.2-cells, which lacked significant self-renewal capability and were mono- or bipotent progenitor cells. Separation of Thy-1.2+ cells into large or small Thy-1.2+ subpopulations showed that only the large Thy-1.2+ colony-forming cells possessed significant self-renewal capacity. Treatment of BDF1 bone marrow with anti-Thy-1.2 plus complement reduced primary colony formation by 67% and eliminated those colony-forming cells which had extensive self-renewal properties. In the presence of PWMSCM, depletion and reconstitution of T lymphocytes had no effect on primary or secondary colony formation. These data demonstrate that Thy-1 is present on primitive hematopoietic stem cells in post-5-FU bone marrow. In addition, they show that the murine S cell is Thy-1+.
authors.forename: D E
authors.initials: DE
authors.lastname: Williams
authors.forename: H S
authors.initials: HS
authors.lastname: Boswell
authors.forename: A D
authors.initials: AD
authors.lastname: Floyd
authors.forename: H E
authors.initials: HE
authors.lastname: Broxmeyer
mesh_terms: D000818:Animals; D000954:Antigens, Surface / Q000032:analysis*; D001854:Bone Marrow Cells; D002454:Cell Differentiation / Q000187:drug effects; D003114:Colony-Forming Units Assay; D003165:Complement System Proteins / Q000502:physiology; D005260:Female; D005434:Flow Cytometry; D005472:Fluorouracil / Q000494:pharmacology*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D007518:Isoantibodies / Q000502:physiology; D051379:Mice; D008806:Mice, Inbred AKR; D013601:T-Lymphocytes / Q000276:immunology; D018800:Thy-1 Antigens; D013997:Time Factors
chemical_list: D000954:Antigens, Surface; D007518:Isoantibodies; D018800:Thy-1 Antigens; C035678:anti-Thy antibody; D003165:Complement System Proteins; D005472:Fluorouracil