Methodological studies on growth of mouse granulocyte/macrophage colonies in methylcelldose‐containing media

Abstract

We studied the influence of various physicochemical parameters on colony development and total cell numbers in 7-day methylcellulose cultures of mouse bone marrow cells. Colony growth was markedly retarded by an increase of PO₂ from ∼, 6.7 kPa towards that in ambient air and by a decrease of incubator temperature from 37°C to 33°C. Medium osmolality above ∼ 340 mosm/kg inhibited formation of granulocytes (in cultures containing growth factors from po-keweed mitogen-stimulated spleen cells), but not macrophages (L cell-produced growth factors). At most, colony growth was affected slightly by moderate changes in pH (7.17-7.47) or concentration of methylcellulose (0.77-1.02%), or by the presence of 2-mercaptoethanol (50 μmol/l), Hepes buffer (25 mmol/l), or eryth-ropoietin (0.1-1 units/rnl). The culture trays could be stored for one day at 4°C in the incubation boxes before colonies or cells were counted.