The effect of human recombinant GM-CSF on the myelopoiesis in a long-term bone marrow culture (LTBMC).

The long-term bone marrow culture (LTBMC) allows continuous self-renewal of a myeloid precursor population from an adherent stromal cell layer. We investigated the effect of human recombinant GM-CSF (100 ng/ml) on the in vitro hemopoiesis in a LTBMC. After a culture period of 14 days we observed a 2.3-fold increase in the total number of non-adherent cells in the cultures containing GM-CSF. Whereas the total cell number in the cultures without GM-CSF decreased after 28 days, proliferation continued in the cultures with GM-CSF. During the first 14 days there was a slight decrease of the number of CFU-GM in the cultures with GM-CSF. Thereafter no significant difference in the numbers of committed progenitors present in two culture systems could be observed.