[Basic studies on granulocyte-macrophage colony formation by mouse bone marrow cells]

In order to study the growth of granulocyte-macrophage colony-forming unit (GM-CFU), fundamental studies on in vitro colony formation were carried out using mouse bone marrow cells by the soft agar culture and the following results were obtained: The number of colonies increased to a maximum level after 4 days of incubation and decreased thereafter. There was a positive correlation between the number of colonies and that of cultured bone marrow cells. There was a linear dose-response relationship between the number of colonies and the concentration of colony stimulating factor (CSF), and the maximum response was obtained at the concentration of 10% CSF. As the fetal calf serum (FCS) dose increased, the number of colonies also multiplied. No significant difference was observed in the colony forming ability between non-separated and separated (non-phagocytic) cells in bone marrow cells. The addition of 2-mercaptoethanol increased doubled the number of colonies at the concentration of 1 X 10(-4) M. The results of these fundamental studies on GM-CFU are thought to be useful for the investigation of granulopoiesis.