THE EFFECT OF MOUSE LUNG GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR AND OTHER COLONY-STIMULATING ACTIVITIES ON THE PROLIFERATION AND DIFFERENTIATION OF MURINE BONE-MARROW CELLS IN LONG-TERM CULTURES

Abstract

The roles of colony-stimulating factors in long-term bone marrow cultures were studied and compared. After single additions of high concentrations of unpurified colony-stimulating activities to the cultures, rapid deterioration of the cultures was observed. This appears to result from contaminants in the stimulatory preparations. Cultures to which one purified colony-stimulating factor (csf) from endotoxin mouse lung-conditioned medium was added did not run down ten weeks after addition and were found to be the same as the controls. The deterioration of the cultures to which unpurified stimulators were added could not be accounted for by accelerated granulopoiesis leading to subsequent exhau..