A simple and rapid radioimmunoassay for human interleukin-6.
Studies were undertaken to develop a sensitive radioimmunoassay for human IL-6 using commercially available reagents. The assay utilized a polyclonal rabbit anti-IL-6 binding to iodinated IL-6; the reaction was carried out in solution and the immune complexes were precipitated using anti-rabbit IgG coupled to magnetic particles. Using a format where sample IL-6 was added in advance of the radiolabelled IL-6, the working range of the assay was found to fall between 0.1 and 10 ng/ml (IC50 around 1 ng/ml) for a 50 microliters sample volume, and was run overnight. However, the assay could be completed in 2 h, using a direct competitive format when less sensitivity is required (working range 1.5-25 ng/ml, IC50 12 ng/ml). The RIA correlated directly with a standard functional assay for IL-6 (proliferation of the mouse hybridoma B9.9) for both recombinant IL-6 and natural IL-6 from human monocytes. The total assay variance was less than 12% and no reactivity with interleukins-1-5 was found. Using the RIA, IL-6 produced in culture by human monocytes in response to various stimuli (LPS, IL-1, dibutyryl cAMP) was measured.
Peppard
J V
JV
Research Department, Ciba-Geigy Pharmaceutical Division, Summit, NJ 07901.
Rediske
J J
JJ
Koehler
J A
JA
Koehne
C F
CF
D003994:Bucladesine / Q000276:immunology; D002478:Cells, Cultured; D004306:Dose-Response Relationship, Immunologic; D006801:Humans; D007375:Interleukin-1 / Q000276:immunology; D015850:Interleukin-6 / Q000032:analysis*; D008070:Lipopolysaccharides / Q000276:immunology; D009000:Monocytes / Q000378:metabolism; D011863:Radioimmunoassay / Q000379:methods*; D012016:Reference Values; D012680:Sensitivity and Specificity
D007375:Interleukin-1; D015850:Interleukin-6; D008070:Lipopolysaccharides; D003994:Bucladesine