Myelopoiesis of human bone marrow cells in a micro-agar culture system: comparison of two sources of colony stimulating activity (CSA).

Human bone marrow cells were grown in a micro-agar culture system in the presence of human placenta (HPCM) and giant cell tumor conditioned media (GCT). The effects of HPCM and GCT conditioned media on linearity, growth dynamics, and morphological composition of colonies were studied after 7 and 14 days of incubation. Under the described conditions the dose-response curves for HPCM and GCT were different: on day 7 maximal stimulation was obtained with 2.5% HPCM and 20% GCT; on day 14 a maximal response was reached with 1.25% HPCM and 5% GCT. Both stimuli produced maximal growth after 7 days of incubation, followed by a rapid decrease in the number of formed colonies up to day 14. The morphological study of aggregates showed that after 7 days of incubation 80% pure granulocyte and 20% mixed granulocyte-macrophage colonies were found in the presence of both stimuli. However, on day 14 the incidence of granulocyte-macrophage colonies increased to 60%, whereas the percentage of pure granulocyte colonies decreased to 20%. The frequency of eosinophil colonies was relatively low (median 15%) with both stimuli. The described system can be applied successfully for studies of myelopoiesis in vitro. Both sources of colony stimulating activitites (CSA) employed had no significant difference in their ability to stimulate myelopoiesis.