Monoclonal antibodies to the thyrotropin receptor: stimulating and blocking antibodies derived from the lymphocytes of patients with Graves disease.

Abstract

Human monoclonal antibodies have been generated from heterohybridomas obtained by fusing mouse myeloma cells with peripheral lymphocytes from patients with active Graves disease. This report characterizes four antibodies as presumptive thyrotropin receptor antibodies because they specifically inhibit thyrotropin binding and competitively inhibit thyrotropin-induced cAMP levels in human thyroid cells. Two of these antibodies, 208F7 and 206H3, are representative of autoimmune stimulators in Graves disease sera because they stimulate thyroid function in all assays, including the mouse bioassay; their ability to inhibit thyrotropin-induced cAMP increases in thyroid cells competitively is complemented by more than additive agonism at low (10 pM) thyrotropin concentrations. These stimulating antibodies interact more potently with human thyroid ganglioside preparations than with bovine thyroid or brain gangliosides; in contrast, they are poor inhibitors of 125I-labeled thyrotropin binding to liposomes containing the glycoprotein component of the human thyrotropin receptor. Antibodies 129H8 and 122G3 appear to be representative of inhibiting or "blocking" antibodies in Graves disease sera. Thus they have no intrinsic stimulatory action in assays of thyroid function but rather inhibit thyrotropin activity in the assays tested. These two antibodies do not react with human thyroid gangliosides but are strong inhibitors of thyrotropin binding to liposomes containing the high-affinity glycoprotein component from human, bovine, and rat thyroid membranes. The data unequivocally establish the pluritopic nature of the immunoglobulins in Graves disease and relate individual components or determinants of the thyrotropin receptor structure with specific autoimmune immunoglobulins.

Characteristics of anti-TSH receptor antibodies in two patients who developed spontaneous hypothyroidism after antithyroid drug therapy for hyperthyroid Graves' disease.

“…Orgiazzi et al (1976) and Carayon et al (1983) reported that blocking antibodies were also present in some patients with hyperthyroid Graves' disease. These findings were confirmed by Valente et al (1982) who derived monoclonal stimulating and blocking antibodies from lymphocytes of patients with Graves' disease.…”

Binding domains of stimulatory and inhibitory thyrotropin (TSH) receptor autoantibodies determined with chimeric TSH-lutropin/chorionic gonadotropin receptors.

“…Contradictory data exist for and against this hypothesis. Evidence and TSH binding-inhibitory activities (22)(23)(24), but none of these antibodies have been proven to be against the TSH receptor. The reported ability of IgG from patients with autoimmune thyroid disease to immunoprecipitate TSH -TSH receptor complexes (25)(26)(27)(28) would also support the existence of separate binding sites for TSH receptor antibodies and TSH.…”

Growth stimulating antibody, as another predisposing factor of Graves’ disease (GD): analysis using monoclonal TSH receptor antibodies derived from patients with GD

“…Although it was also reported that the MAPK pathway was activated by monoclonal TSAb derived from an animal model or a patient with GD, its functional role has not been examined [22,27]. Valente et al demonstrated that TSBAb derived from a patient with GD induced thyrocyte growth, however, they did not analyze its signaling pathway [28]. In this study, we first showed that a MEK inhibitor suppressed thyrocyte growth stimulated by monoclonal TRAb but not by TSH/Fsk.…”