A highly sensitive electrochemiluminescence immunoassay for interferon alfa-2b in human serum

A highly sensitive immunoassay for the quantitative measurement of recombinant interferon alfa-2b (IFN alfa-2b) in serum was developed using the ORIGEN electrochemiluminescence (ECL) detection system. The ECL assay developed uses a ruthenylated mouse monoclonal anti-IFN-alfa antibody and a sheep polyclonal anti-IFN-alfa antibody that has been biotinylated. An immune complex, formed between the antibodies and the IFN in the serum, is captured by streptavidin coated paramagnetic beads. The assay is sensitive and can accurately measure 4 IU/ml in undiluted serum samples. In addition, this assay requires less labor than classical ELISAs and is not significantly affected by individual serum factors. The total assay variance for both intra- and inter-assay precision is < 10%. The assay is specific for the analyte. Mean percent recoveries in pooled and individual donor serum samples range from 84 to 114%. In addition, results of the ECL assay correlate well with a bioassay and were more accurate that an ELISA for the detection of interferon alfa-2b in individual human serum samples. The assay can be modified to measure other forms of the analyte and/or interferon in other matrices.