Development of immunoradiometric assays for human thyroglobulin using monoclonal antibodies and the biotin/avidin system.

Monoclonal antibodies against human thyroglobulin were produced by the hybridoma technique. Using three non-crossreactive monoclonal antibodies, an IRMA system was developed, with a polyclonal rabbit antibody fixed on microtiter plates as first extracting antibody. The monoclonal antibodies were used as second antibody, while anti-mouse IgG-biotin from goat and [125I]streptavidin served as the indicator system. The source of the monoclonal antibodies was diluted culture medium without purification. Sensitivities of 3-4 micrograms/l were obtained with all 3 monoclonal antibodies; interassay variation was about 5%. This test system will be used for further immunological characterization of circulating thyroglobulin in different thyroid diseases.