Continuous growth and differentiation of human myeloid leukaemic cells in suspension culture.

TLDR: The derivation from myeloid leukaemic cells of a leukocyte culture is described here for the first time that by morphological and histochemical criteria clearly and persistently differentiates along the myeloids series without an exogenous source of conditioned medium.

Abstract: ATTEMPTS to develop long-term suspension cultures of human myeloid leukaemic cells have met with limited success. Lymphoblastoid lines carrying the Epstein–Barr virus genome occasionally arise during such attempts but these lymphoid cells originate from contaminating B lymphocytes and not from the leukaemic myeloid cells1. A line established from the pleural fluid of a patient with chronic myeloid leukaemia in blast crisis2 (designated K-562) has no B-cell or T-cell markers3–4 and does not seem to be of lymphoid origin4. Its lack of morphological and histochemical differentiation2–4, however, makes it difficult to determine whether these cells are derived from myeloblasts or more primitive stem cells4. Another less documented cell line (8261) derived from the peripheral blood of a patient with acute myelogenous leukaemia showed apparent morphological and functional differentiation in agar in the presence of a feeder layer of peripheral blood leukocytes but did not differentiate in suspension culture5. Our laboratory previously reported that cultures of differentiating myeloid leukaemic cells can be maintained for several months in suspension culture but only when enriched with conditioned media (CM) from certain monolayer fibroblastic cultures of first trimester whole human embryos (ref. 6 and Ruscetti et al. in preparation). We describe here for the first time the derivation from myeloid leukaemic cells of a leukocyte culture that by morphological and histochemical criteria clearly and persistently differentiates along the myeloid series without an exogenous source of conditioned medium.