International Journal of Cell Cloning, Vol 6, 262-280, Copyright © 1988 by AlphaMed Press
Thymic dependency of the humoral regulation of CFU-s proliferation in mice bearing a CSF-producing tumor
F Lepault, MP Fache and E Frindel
Laboratoire de Cinetique Cellulaire, INSERM Unite 250, Institut Gustave- Roussy, Villejuif, France.
A better understanding of the mechanisms involved in the proliferation of
splenic colony-forming units (CFU-s) during tumor growth is important for
the prevention of bone marrow aplasia during chemotherapy. The in vivo
growth of EMT6 cells, a colony-stimulating factor-secreting mammary tumor,
in BALB/c and nude mice resulted in splenomegaly and an increase in the
number of splenic granulocyte/macrophage colony-forming cells (GM-CFC).
Proliferation of CFU-s, observed in BALB/c mice but not in nude mice, most
likely resulted from combined direct and indirect actions of factors
secreted by tumor and host cells (in particular helper T cells). These
factors were detectable in the serum immediately following tumor cell
injection. Thus, the GM-CFC response to factors secreted by the EMT6 tumors
is thymus-independent while the CFU-s response is dependent upon the
presence of T cells. Finally, we show that EMT6 tumor growth had no effect
on the determination of CFU-s differentiation toward the various myeloid
cell lineages.
