Differentiation to myeloid cells of lymphoblastoid cells established from myelomonocytic leukemia

Summary It has been previously reported that a lymphoblastoid cell line (Mono-1) established from the peripheral blood of a patient with acute myelomonocytic leukemia (AMML) consisted of reticulum cells, possessing properties that were more characteristic of monocytes and macrophages than those which are traditionally attributed to lymphocytes. These cells (Mono-1-207) exhibit myeloid cell properties when cultured in arginine-deficient medium and after treatment with DNA synthetic inhibitors. A comparison has been made with lymphoblastoid cell lines derived from other types of disease.During culture in arginine-deficient condition, decreased DNA synthesis is accompanied by the appearance, at 48 h, of perinuclear pink cytoplasmic blushes; nuclear lobulation had developed by about the fifth day. At 12–14 days, the cytoplasmic granules developed from blushes could not be distinguished from azurophilic granules. Electron microscopy indicated that these granules were due to the development of lysosomes in which acid phosphatase was strongly present but which lacked any peroxidase activity. Mono-1-207 also has phagocytic activity. It is considered that the induction of differentiation of these cells in response to DNA synthesis by arginine-deficiency is related to possession of the characteristics described: they are hemopoietic precursor cells, and differentiate to myeloid cells.This work was supported by a cancer research grant 51101 and 52004 from Kawasaki Medical School.