A bioassay for the measurement of human interleukin-4

• Published in: Journal of immunological methods Vol. 132; no. 2; p. 287
• Main Authors: Siegel, J P, Mostowski, H S
• Format: Journal Article
• Language: English
• Published: Netherlands 14-09-1990
• Subjects: Antigens, CD - analysis; Antigens, Differentiation, B-Lymphocyte - analysis; Biological Assay; Burkitt Lymphoma; Clone Cells; Cytokines - pharmacology; Flow Cytometry; Humans; In Vitro Techniques; Interferons - pharmacology; Interleukin-4 - analysis; Receptors, Fc - analysis; Receptors, IgE; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha - pharmacology
• ISSN: 0022-1759
• DOI: 10.1016/0022-1759(90)90040-3

We have developed a bioassay for human IL-4 based upon its ability to upregulate CD23 (low affinity IgE receptor) expression. Ramos, a B lymphocyte line derived from a Burkitt lymphoma, was repetitively subcloned yielding a clone, Ramos.G6.C10, which is several fold more sensitive to this effect of IL-4. In microtiter plates cells were cultured for 48 h in the presence of dilutions of recombinant human IL-4 or samples, and then stained with murine anti-human CD23 and goat anti-mouse IgG-FITC. IL-4 induced an eight-fold increase (60 channel shift) in fluorescence intensity as measured by flow cytometry. Significant effects were observed at an IL-4 concentration of 50-100 pg/ml and increased with concentrations up to 800 pg/ml. Inter- and intra-assay coefficients of variation were 10% and 11% respectively. The bioassay showed good specificity for IL-4; however, tumor necrosis factors alpha and beta, at optimal concentrations, gave readings barely at the threshold of detection.