Quantitative in vivo assay of human granulocyte colony-stimulating factor
using cyclophosphamide-induced neutropenic mice
K Hattori, K Shimizu, M Takahashi, M Tamura, M Oheda, N Ohsawa and M Ono
Fuji-Gotemba Laboratory, Chugai Pharmaceutical Co Ltd, Gotemba, Japan.
Administration of human granulocyte colony-stimulating factor (hG-CSF) to
mice with cyclophosphamide (CPA)-induced neutropenia for 4 consecutive days
from the day after the CPA dosing (100 mg/kg) resulted in a dose-dependent
increase in the peripheral blood neutrophil count 6 hours after the final
hG-CSF injection. Within the hG-CSF dose range of 0.1 to 10 micrograms per
mouse per day, there was a strong linear relationship (r greater than .9)
between the logarithm of the dose and the peripheral blood neutrophil count
in the treated mice. Using the same hG-CSF preparation, 38 experiments
indicated that the regression lines are highly reproducible. Such an
association never occurred with intact mice, and 100 mg/kg of CPA induced
the highest response to hG- CSF. This linear relationship between the two
variables allows us to determine the biologic potency of a test hG-CSF
preparation relative to a reference standard using a parallel line assay,
with a coefficient of precision of around .2. When assayed by this bioassay
procedure, which we have termed CPA-mouse assay, natural hG-CSF and
recombinant hG-CSF (produced by Chinese hamster ovary cells) were nearly
equipotent in specific biologic activity. These results confirm the
CPA-mouse assay as an especially useful assay method for quantifying the in
vivo activity of hG-CSF.
Volume 75,
Issue 6,
pp. 1228-1233,
03/15/1990
Copyright © 1990 by The American Society of Hematology
