Quantitative in vivo assay of human granulocyte colony-stimulating factor using cyclophosphamide-induced neutropenic mice.
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.
Fuji-Gotemba Laboratory, Chugai Pharmaceutical Co Ltd, Gotemba, Japan.
K
K
Hattori
K
K
Shimizu
M
M
Takahashi
M
M
Tamura
M
M
Oheda
N
N
Ohsawa
M
M
Ono
D000380:Agranulocytosis / Q000378:metabolism*; D000818:Animals; D002452:Cell Count / Q000187:drug effects; D003115:Colony-Stimulating Factors / Q000032:analysis* / Q000494:pharmacology; D003520:Cyclophosphamide; D004305:Dose-Response Relationship, Drug; D016179:Granulocyte Colony-Stimulating Factor; D006410:Hematopoiesis / Q000187:drug effects; D008297:Male; D008722:Methods; D051379:Mice; D008815:Mice, Inbred Strains; D009503:Neutropenia / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology; D009504:Neutrophils / Q000032:analysis / Q000187:drug effects / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology
D003115:Colony-Stimulating Factors; D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor; D003520:Cyclophosphamide