Measurement of mouse and human interleukin 5

Two fundamentally different types of assays are available for quantitating interleukin 5 in biological samples. One type, a bioassay, is based on the ability of IL-5 to enhance B cell proliferation and immunoglobulin secretion or eosinophil proliferation and differentiation. The other type of assay, an ELISA, uses antibodies against IL-5 to capture and quantitate IL-5 in samples. Advantages and disadvantages of each assay are discussed. The bioassay described in this unit, utilizing BCL(1) cells as the indicator line, has been designed primarily to assay murine IL-5; however, it can also be used to measure human IL-5. The IL-5 ELISA, while sensitive and specific, provides no information about biological activity.