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L Lu, D Walker, CD Graham, A Waheed, RK Shadduck and HE Broxmeyer
Department of Medicine, Indiana University School of Medicine, Indianapolis
46223.
The influence of purified recombinant human tumor necrosis factor-alpha
(rhuTNF-alpha) was assessed alone and in combination with purified
recombinant human interferon gamma (rhuIFN-gamma) for its effects on
enhancing release from human monocytes of activities that stimulate colony
formation by granulocyte-macrophage (CFU-GM), erythroid (BFU-E), and
multipotential (CFU-GEMM) progenitor cells. RhuTNF-alpha or rhuIFN- gamma
enhanced release of colony stimulating factors (CSFs), which were
determined by a combination of human and mouse colony assays, morphological
assessment of colony types and neutralization studies with anti-human
macrophage CSF (CSF-1) and anti-human granulocyte (G)- CSF to be CSF-1 and
G-CSF. The activity in the uninduced and induced monocyte conditioned media
(CM) for CFU-GM-type colonies and clusters was attributed to the presence
of both CSF-1 and G-CSF, while the activity in the monocyte CM for BFU-E
and CFU-GEMM colonies was attributed to the presence of G-CSF. Monocytes
were separated by two- color fluorescence using a dye laser flow cytometry
system with cells labeled with anti-leu M3 conjugated with fluorescein
isothiocyanate and anti-HLA-DR conjugated with phycoerythrin. While
"constitutive" release of CSFs from monocytes was apparent from both the
leu M3+, HLA-DR+ and the leu M3+, HLA-DR- (low density or negative DR)
fractions, enhanced release of CSFs in response to rhuTNF-alpha or
rhuIFN-gamma was confined to the leu M3+, HLA-DR+ population of cells.
RhuTNF-alpha and rhuIFN-gamma synergized to enhance release of CSFs such
that low concentrations of each molecule, which were inactive when used
alone, were active when the two molecules were used together. These studies
suggest a role, at least in vitro, for TNF-alpha and IFN-gamma in the
release of CSFs from cells of the mononuclear phagocytic lineage.
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| Copyright © 1988 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||