Myeloid colony-forming cells express human B lymphocyte antigens

Abstract

STUDIES in experimental animals suggest that lymphoid and myeloid cells share a common stem-cell precursor¹, but human lymphoid–myeloid stem cells have been difficult to document. Indirect evidence for such cells has come from recent observations that human B lymphocyte antigens occur not only on B lymphocytes but also on monocytes and leukaemic myeloblasts^2–6. If normal immature myeloid cells, like leukaemic myeloblasts, share a common differentiation antigen with B lymphocytes, it would seem even more likely that myeloid cells and B lymphocytes share a common stem-cell precursor. We have therefore compared the ability of bone marrow cells to form macrophage–granulocyte colonies in vitro after complement-mediated lysis of cells expressing either human B-lymphocyte antigens (HBLA) or human T-lymphocyte antigens (HTLA). Our results show that macrophage–granulocyte colony-forming cells (CFU-C) express HBLA but not HTLA antigens.