COMPETITIVE ENZYME-IMMUNOASSAY FOR QUANTIFICATION OF THE CELLULAR-FORM OF FIBRONECTIN (EDACFN) IN BLOOD-SAMPLES

A competitive enzyme immunoassay based on the monoclonal antibody DH1 was developed for the quantification of extradomain A (EDA)-containing isoform of cellular fibronectin (cFN). The average EDAcFN concentrati on in normal plasma was 2.46 mug/ml and in serum 0.68 mug/ml. Similar results were obtained by gelatin-Sepharose binding and immunoblotting. Studies on the effect of storage of plasma and serum as frozen sample s indicated that the amount of EDAcFN decreased rapidly when stored at -20-degrees-C. Storage at -70-degrees-C resulted in less of a decreas e in the concentration of EDAcFN. The method permits the determination of EDAcFN in blood samples from diseases showing increased amounts of the protein at the tissue level.