A sandwich enzyme-linked immunosorbent assay for human interleukin-5

A sandwich enzyme-linked immunosorbent assay (ELISA) was developed for human interleukin-5 (hIL-5) using a combination of monoclonal anti-recombinant(r)-hIL-5 antibody and rabbit anti-r-hIL-5 IgG. Detection limit of this assay was estimated to be 7.8 pg/ml, which was about 10,000 times more sensitive than that of the bioassay using BCL1 cells of murine origin. This ELiSA was specific for hIL-5, showing no crossreactivity to recombinant human GM-CSF, IL-4, TNF-alpha, IFN-gamma and mouse IL-5 (mIL-5). The presence of 10% fetal calf serum did not interfere with the measurement of r-hIL-5. Coefficients of variation in intra-assay and interassay were 1.1-4.6% and 2.3-11.3%, respectively. These results indicate that this assay system can be quite useful in quantifying hIL-5 in various biological fluids.