Development of a competitive radioimmunoassay and a sandwich enzyme-linked immunosorbent assay for recombinant human granulocyte colony-stimulating factor. Application to a pharmacokinetic study in rats.

A competitive radioimmunoassay (RIA) and a sandwich enzyme-linked immunosorbent assay (ELISA) for the measurement of recombinant human granulocyte colony-stimulating factor (rhG-CSF) in rat serum was developed using polyclonal antibody obtained by immunizing rabbits with rhG-CSF. The anti-rhG-CSF antibody did not recognize other colony-stimulating factors or interleukins. RIA and ELISA gave satisfactory reproducibility as judged by intra- and inter-assay precision. Good agreements between the RIA, ELISA and bioassay were observed with rat serum samples after administration of rhG-CSF. The competitive RIA and sandwich ELISA described here appear to be as equally useful as the bioassay in studying the pharmacokinetics of rhG-CSF in animals.