A biologic assay for IL-4. Rapid fluorescence assay for IL-4 detection in supernatants and serum.
Interleukin-4 (IL-4) is a lymphokine produced by activated T helper cells with effects on T cells, B cells, monocytes and mast cells. The conventional tonsillar B cell assay used for quantification of IL-4 activity is sensitive to the presence of other cytokines and requires the acquisition of fresh cells on a regular basis. We have evaluated the ability of IL-4 in the presence of antibody to IgM to induce CD23 on a cultured B cell line (Ramos) The requirements of measuring hundreds of samples at a single time precluded ready use of a conventional flow cytometer. We therefore developed a rapid fluorescence assay which allows the detection of IL-4 in supernatants and serum. The use of a particle fluorescence immunoassay reproducibly allows detection of IL-4 to 6 U in supernatants and serum. This assay is specific for IL-4 and is not sensitive to other recombinant cytokines including IL-1, IL-2, IL-3, IL-6; interferon-alpha, -beta or -gamma, tumor necrosis factor (TNF) or GM-CSF. Finally, in cancer patients receiving IL-4 its detection in serum using this assay reveals an alpha distribution phase of approximately 8 min and a beta clearance phase of approximately 48 min.
Custer
M C
MC
Division of Cancer Treatment, National Cancer Institute, Bethesda, MD 20892.
Lotze
M T
MT
D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis; D001402:B-Lymphocytes / Q000032:analysis; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D005453:Fluorescence; D006801:Humans; D007118:Immunoassay; D015847:Interleukin-4 / Q000032:analysis*; D008213:Lymphocyte Activation; D011961:Receptors, Fc / Q000032:analysis; D017455:Receptors, IgE
D000944:Antigens, Differentiation, B-Lymphocyte; D011961:Receptors, Fc; D017455:Receptors, IgE; D015847:Interleukin-4