An idiotypic-anti-idiotypic competitive immunoassay for quantitation of okadaic acid

A competitive indirect enzyme-linked immunosorbent assay for the measurement of okadaic acid, a marine toxin, was developed. The assay uses a murine monoclonal anti-idiotypic antibody bearing an internal image of okadiac acid epitope to capture an anti-okadaic acid monoclonal antibody in the presence of free okadaic acid. Bound anti-okadaic acid antibody is detected with peroxidase-conjugated anti-mouse immunoglobulin antiserum. If present, free toxin will lessen the amount of anti-okadaic acid antibody binding to its corresponding anti-idiotypic antibody in a dose-dependent manner that can be quantified from the standard curve. The assay permits reliable measurement of okadaic acid in the 9-81 ng/ml range. The intra- and interassay coefficients of variation in the measurement of OA in the toxin spiked mussel samples averaged 9% and 12%, respectively. The assay is rapid, accurate, reproducible and relatively simple to perform. It may be of potential use to laboratories involved in monitoring the toxin levels in plankton, seafood or sponges.