IN-VIVO STIMULATION OF THYROID-HORMONE RELEASE BY RABBIT ANTIBODIES WITH THYROID-STIMULATING ACTIVITY RAISED AGAINST THE MUTATED RECEPTOR PEPTIDE TSH-R-HIS(17)

The present study was designed to examine whether thyroid stimulating antibodies (TSAb) against the mutated or non-mutated peptide of human TSH receptor stimulates release of thyroid hormones in mice in vivo. W e generated antibodies against mutated TSH receptor peptide TSH-R-HIS1 7 and non-mutated TSH receptor peptide TSH-R-ASP17 immunizing the pept ides to rabbits. We isolated immunoglobulin G (IgG) from these antibod ies and injected iv into male ddy mice. Control mice were injected iv with bTSH or TSAb-negative normal rabbit IgG. Serum T3 and T4 concentr ations were elevated after the administration of bTSH in a dose-depend ent manner. Serum T3 and T4 concentrations were significantly elevated after the injection of IgG from the rabbit antibodies with TSAb activ ity produced against TSH-R-HIS17. However serum T3 and T4 remained wit hin normal levels after the injection of IgG from the rabbit antibodie s without TSAb activity toward TSH-R-ASP 17. The present data offer in vivo support of the IgG with TSAb activity interaction with the TSH r eceptor of the thyroid and raise the possibility that TSAb against mut ated human TSH receptor peptide might be contributed to induce thyroid hyperfunction.