Production and characterization of monoclonal antibodies against human thyroglobulin.

Spleen cells of Biozzi-HR mice immunized with human thyroglobulin (hTg) were fused with P3-X63-Ag8.653 mouse myeloma cells. Twenty monoclonal antibodies (MAbs) selected by an enzyme immunoassay (indirect ELISA) were produced, purified and characterized. The equilibrium association constant (Ka) of one of the MAbs, determined by Scatchard analysis of the ELISA data, was found to be 2 X 10(9) M-1; the Ka of the other MAb, estimated from titration curves by comparison with the aforementioned MAb, ranged from 8 X 10(9) M-1 to 6 X 10(7) M-1. The reaction between the MAb and hTg was not inhibited by thyroxin (T4), triiodothyronine (T3) and triiodothyropropionic acid (DT3). Species specificity of the MAb was studied using bovine and porcine Tgb. The topology of the MAb was investigated by competitive inhibition immunoassays. Seven distinct antigenic regions were identified.