title: Monoclonal antibody BA-1 does not bind to hematopoietic precursor cells.
abstract: Monoclonal antibody BA-1 binds to B lymphocytes, to cells from most cases of non-T acute lymphoblastic leukemia (ALL), and weakly to neutrophils. To determine whether BA-1 also reacts with hematopoietic progenitor cells (HPC), we studied the effect of removal of BA-1+ cells from human bone marrow on the proliferation in vitro of the trilineage precursor cell CFU-GEMM, and on the committed progenitor cells of granulopoiesis (CFU-C) and erythropoiesis (BFU-E/CFU-E). Complement-mediated cytotoxicity using BA-1 at concentrations far beyond those required to lyse BA-1+ bone marrow cells and ALL cells did not result in inhibition of colony formation in any of the assays. A rosette separation method, using ox red blood cells coated with BA-1, resulted in enrichment of HPC in the BA-1-depleted interface, whereas very few HPC were found in the BA-1-enriched pellet. Both methods indicate that BA-1 does not bind to HPC, although binding of the antibody to the lymphohematopoietic stem cell cannot be excluded yet. The high cytotoxic capacity of the IgM antibody BA-1, and the lack of reactivity with HPC, make the antibody particularly suitable for use in autologous bone marrow transplantation for patients with ALL.
mesh_terms: D000293:Adolescent; D000328:Adult; D000911:Antibodies, Monoclonal / Q000378:metabolism*; D001666:Binding Sites, Antibody; D001853:Bone Marrow / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003601:Cytotoxicity Tests, Immunologic; D005455:Fluorescent Antibody Technique; D006098:Granulocytes / Q000276:immunology; D006412:Hematopoietic Stem Cells / Q000276:immunology*; D006801:Humans; D008264:Macrophages / Q000276:immunology; D012397:Rosette Formation
chemical_list: D000911:Antibodies, Monoclonal