[Analysis of epitopes for TSH receptor autoantibodies using TSH receptor/LH-CG receptor chimeras]

Graves' disease and idiopathic myxedema are autoimmune thyroid diseases and are caused by thyrotropin (TSH) receptor autoantibodies, thyroid stimulating antibody (TSAb) in Graves' disease and thyroid stimulation blocking antibody (TSBAb) in idiopathic myxedema. Studies with TSH receptor/lutropin-chorionic gonadotropin (LH-CG) receptor chimeras show that binding sites or epitopes on human TSH receptor for TSH, TSAb and TSBAb are different and, moreover, epitopes for TSAb are heterogeneous in different Graves' patients. Epitopes for TSAb exist in the N-terminal region and those for TSBAb in the C-terminal region on human TSH receptor extracellular domain.