title: Specific antibodies to mouse Sca-1- (Ly-6A/E) or Thy-1-positive haematopoietic progenitor cells induce formation of nitric oxide which inhibits subsequent colony formation.
abstract: Mouse bone marrow cells were exposed to specific monoclonal antibodies, so that lineage positive (Lin+) cells could be removed with magnetic beads. The Lin- cells were cultured with Sca-1 or CD90 (Thy-1) monoclonal antibodies (MoAbs) in semi-solid medium for 7 d. We found that Sca-1 MoAb suppressed colony formation (20-30%), and the effect was largely abolished by N-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide (NO) synthase. Similar results were obtained with antibodies to CD90. The findings suggest that the unknown physiological ligands to Sca-1 and Thy-1 markers on haematopoietic progenitor cells can inhibit colony formation, with NO as a pivotal mediator. Primitive progenitors may be a primary target of this Sca-1 ligand, as the Sca-1+ cell population contains the major part of the multipotent haematopoietic stem cells.
authors.affiliation: Amersham Health AS, Oslo, Norway. arneboy@basalmed.uio.no
authors.forename: Arne
authors.initials: A
authors.lastname: Bøyum
authors.forename: Hege B
authors.initials: HB
authors.lastname: Fjerdingstad
authors.forename: Vivi-Ann
authors.initials: VA
authors.lastname: Tennfjord
authors.forename: Haakon B
authors.initials: HB
authors.lastname: Benestad
authors.forename: Dagfinn
authors.initials: D
authors.lastname: Løvhaug
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology*; D000918:Antibody Specificity; D000950:Antigens, Ly / Q000276:immunology*; D002455:Cell Division / Q000187:drug effects; D019070:Cell Lineage; D002478:Cells, Cultured / Q000187:drug effects / Q000276:immunology; D003114:Colony-Forming Units Assay; D005260:Female; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D008565:Membrane Proteins / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009569:Nitric Oxide / Q000096:biosynthesis* / Q000502:physiology; D018800:Thy-1 Antigens / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000950:Antigens, Ly; C074650:Ly6a protein, mouse; D008565:Membrane Proteins; D018800:Thy-1 Antigens; D009569:Nitric Oxide