[Secretion of a granular colony-stimulating factor by an adherent layer of long-term hematopoietic bone marrow cultures in mice].

The presence of a CSF activity in long term bone marrow cultures in Mice was not described until now. Using a double layer agar technique directly on the adherent layers of the cultures, a strong CSF activity is detected in these adherent layers, before recharging the cultures at the third week, or when the cultures are not recharged. The role of this activity in long term myelopoiesis maintenance in vitro is discussed.