Monoclonal antibody BA-1 does not bind to hematopoietic precursor cells
J Jansen, RC Ash, ED Zanjani, TW LeBien and JH Kersey
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.
Volume 59,
Issue 5,
pp. 1029-1035,
05/01/1982
Copyright © 1982 by The American Society of Hematology
