Enhancement of colony-forming activity of granulocyte-macrophage colony-
stimulating factor by monocytes in vitro
M Namiki and H Hara
Division of Blood Transfusion, Hyogo College of Medicine, Japan.
Human recombinant granulocyte-macrophage colony-stimulating factor
(hrGM-CSF) stimulated granulocyte-macrophage (GM) colony formation from
human marrow mononuclear cells (MMCs) in a dose-dependent manner in
methylcellulose culture. When phagocytes were depleted from MMCs, GM colony
formation from the phagocyte-depleted (PD) MMCs by hrGM-CSF markedly
decreased. Experiments in which PD-MMCs were cultured with hrGM-CSF and
adherent cells showed that 94% (on day 7 and day 14) of the colonies from
PD-MMCs were dependent on the presence of adherent cells. In contrast, the
ability of granulocyte colony-stimulating factor (G-CSF) to form colonies
was not affected by phagocyte depletion. To check for the presence or
absence of progenitors that could form GM colonies in direct response to
hrGM-CSF, single-cell culture of hematopoietic progenitor cell surface
antigen (My-10)- positive PD-MMCs was carried out using a flow cytometer
and an Autoclone System. In duplicate experiments, 0.7% and 3.5% (day 7) or
3.6% and 3.9% (day 14) of My-10-positive PD-MMCs formed GM colonies in
response to hrGM-CSF and 5.1% and 6.0% (day 7) of My-10-positive PD- MMCs
formed GM colonies in response to G-CSF. This was clear evidence for the
presence of progenitors directly responding to hrGM-CSF. Also observed was
a synergistic effect on GM colony formation in which more My-10-positive
PD-MMCs stimulated by hrGM-CSF and G-CSF could form GM colonies than the
sum of those stimulated by each separately. This enhancing effect of
colony-forming activity of hrGM-CSF by adherent cells and the single cell
culture experiment were reproduced in serum- free culture system.
Volume 74,
Issue 3,
pp. 918-924,
08/15/1989
Copyright © 1989 by The American Society of Hematology
