Applications of a monoclonal antibody to human ferritin in various immunoassays.

Monoclonal antibodies to human liver ferritin were generated by an improved hybridoma technique using a semisolid medium containing methylcellulose for initial cloning after the cell fusion. Out of more than 1000 hybrid clones, only 1 was shown to secrete high-affinity monoclonal antibodies to human liver ferritin. The immunoglobulin subclass of this antibody was determined to be IgG2. The association constant between liver ferritin and this antibody was determined to be greater than 1 X 10(10) M-1. Due to the oligomeric nature of ferritin, this antibody can be simultaneously utilized as the first and second antibody in solid-phase sandwich immunoradiometric and enzyme immunoassays. This immunoassay procedure can be performed within 30-45 min and has a sensitivity of about 1 ng/ml. Under identical assay conditions, ferritin isolated from human spleen and human heart gave 50 and 30% cross-reactivity, respectively.