DETERMINATION OF TENASCIN IN HUMAN SERUM BY THE USE OF A NEW ENZYME-IMMUNOASSAY

A sandwich-type enzyme immunoassay for tenascin (TN) was established b y the use of two anti-human TN monoclonal antibodies and human TN prod uced by human melanoma cells as a standard. The assay system consists of polystyrene balls (6.5 mm in diameter) with immobilized first monoc lonal antibody F(ab')2 fragments and the other antibody F(ab')2 fragme nts labeled with beta-D-galactosidase from Escherichia coli. The assay system has a minimum detectable sensitivity of 2 ng per assay tube, b eing sufficiently sensitive for the determination of serum TN concentr ations with a satisfactory precision. Serum TN concentrations of healt hy subjects were less than 2.0 mg per liter (n=29, mean +/- SD, 0.897 +/- 0.250 mg per liter) and those in sera of some patients with carcin oma were enhanced (n=47, mean +/- SD, 2.546 +/- 1.746 mg per liter).