Immunodetection of TSH receptor antibodies in sera of patients with autoimmune thyroid disease by ELISA (enzyme-linked immunosorbent assay).

An ELISA system has been developed for detecting antibodies to TSH receptor peptides. It has been used to study antibodies against peptides corresponding to four different extracellular domains of human TSH receptor in the sera of patients with Graves' disease (N = 10, TBII positive) and Hashimoto's disease (N = 10, TBII negative). Two peptides, N (amino acid residues nos. 29-57) and P3 (nos. 359-371) are specific for TSH receptor, and two, C (nos 172-202) and P1 (nos. 398-417) are homologous with the corresponding portions of the LH/CG receptor. All of the peptides were recognized by sera from patients with Graves' disease but individual sera recognized different numbers and combinations of these peptides. Sera from patients with Hashimoto's disease did not bind to any of these peptides. These results suggest that antibodies to the TSH receptor in patients with Graves' disease recognize various regions of extracellular domain of TSH receptor in addition to TSH receptor-specific regions.