Long-term suspension cultures of human cord blood myeloid cells

A method is described that allows for the routine long-term (greater than 3 mo) growth of normal, immature human myeloid cells in liquid suspension culture. The techniques employ cell separation, utilization of special growth conditions (RPMI with hydrocortisone and vitamin D), and cord blood as the source of leukocytes. These cultures are composed predominantly of immature myeloid cells that have grown for over 3 mo in culture but eventually terminate as differentiated, mature granulocytes and monocyte-macrophages. Application of these techniques to other sources of fresh human leukocytes (bone marrow and adult peripheral blood) resulted in only short-term proliferation of myeloid cells. The techniques described can be used for the routine expansion of immature myeloid and monocytoid cell populations, particularly from newborns, and should be useful for systematic studies of normal myeloid- monocytoid cell growth and differentiation and providing normal control cells in studies employing human leukemic myeloid cells.