AN ANTIPROLIFERATIVE BIOASSAY FOR INTERLEUKIN-4

Interleukin-4 (IL-4) is currently being used for therapeutic intervent ion in a wide range of malignant diseases as an antitumour agent. Alth ough bioassays have been developed that measure the proliferative capa city of IL-4, none measure the antiproliferative activity of this mole cule. We have developed a simple, sensitive bioassay for human IL-4 ba sed on the ability of this cytokine to inhibit the proliferation of th e human lung carcinoma line, CCL-185, an easy to maintain, cytokine in dependent, cell line. It is rapid, reproducible and sensitive, able to detect 2 pg/ml IL-4. The assay is completely unresponsive to all othe r interleukins from IL-2 to IL-12, to the colony stimulating factors a nd transforming growth factor beta and is 100-fold less sensitive to i nterferon-alpha, tumour necrosis factor-alpha, IL-1 beta and IL-13. Th e assay can be made completely specific for IL-4 by including specific neutralizing antibodies for IL-4 and is suitable for the estimation o f IL-4 in both plasma and serum samples.