Differences in TSH Receptor Binding and Thyroid-stimulating Properties between TSH and Graves' IgG. Slowly-acting TSH Receptor Antibody Moieties in Graves' Sera Affect Assay Data

Endocrine Journal

Toru MORI¹  Takashi ISHIHARA²  Katsuji IKEKUBO³  Yasuhiko SAIKI³ 

[1] Department of Internal Medicine, Kyoto Senbai Hospital;Department of Endocrinology, Kobe City General Hospital;Department of Nuclear Medicine, Kobe City General Hospital

关键词: TSH receptor;    TSH;    TSH receptor antibody (TRAb);    Thyrotropin-binding inhibitor immunoglobulin (TBII);    Thyroid stimulating antibody (TSAb);   

DOI  :  10.1507/endocrj.52.45

学科分类：内分泌与代谢学

来源: Japan Endocrine Society

【 摘 要 】

References(40)Cited-By(2)We analyzed TSH receptor (TSHR) effects, both binding and thyroid-stimulation, of TSH and Graves' IgG. A new TRAb assay system utilizes rhTSHR coated tubes and is comprised of two step incubation, the first incubation with patient serum followed by a second incubation with 125I-bTSH. We called TRAb measured by this method as hTRAb. 125I-bTSH binding capacity of the tube was found close to saturation at 1 hr with 200 μl of 125I-bTSH. Up to 5 hr of first incubation for hTRAb assay revealed significant increases in all hTRAb activities. hTRAb was not affected by second incubation time or dose of 125I-bTSH. When 1 step incubation with 125I-bTSH and Graves' serum was performed, hTRAb again increased significantly with time. A simple competitive equilibrium model could not be applied to these ligands. Second, Graves' IgG and bTSH were compared for in vitro thyroid-stimulation sequentially up to 24 hr, measuring cAMP generation from cultured porcine thyrocytes. While bTSH yielded peak cAMP generation by 8 hr, TSAb revealed more cAMP generation by 24 hr than at 8 hr. We concluded that individual Graves' sera contain heterogeneous TRAb of variable avidities, and that slow-acting TRAb, which may lack biological activity, can be detected by prolonged incubation.

【 授权许可】

Unknown