Promotion of erythropoietic bursts in culture of human bone marrow by blood-derived Mononuclear cells.

In this report we give evidence that the addition of different amounts of irradiated mononuclear cells (MNC) from normal blood to bone marrow cell cultures containing erythropoietin produces an increase in number and size of erythropoietic bursts proportional to the number of irradiated MNC added. There was no consistent difference in the use either of autologous or of allogeneic MNC as burst-promoting activity source in normal individuals. Plating efficacy studies demonstrated that the number of BFU-E detected had a linear relationship to the number of bone marrow cells plated when 5 X 10(5) blood MNC were present as BPA source. A comparison between different preparations of human leukocyte conditioned media and 5 X 10(5) irradiated MNC, demonstrated that in all experiments irradiated cells stimulated the growth of a higher number of marrow-derived BFU-E. Therefore the use of 5 X 10(5) irradiated MNC from normal blood is proposed as standard BPA source in human bone marrow erythropoietic cultures.