Dual mechanism of perturbation of thyrotropin-mediated activation of thyroid cells by antibodies to the thyrotropin receptor (TSHR) and TSHR-derived peptides

Rajesh K. Desai, John S. Dallas, Manjula K. Gupta, Gattadahalli S. Seetharamaiah, Ji Lao Fan, Kazuo Tahara, Leonard D. Kohn, Bellur S. Prabhakar

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

To further define the epitopes with which anti-TSH receptor (anti-TSHR) antibodies react and mediate their biological effects, we used antibodies against the extracellular domain of TSHR (ETSHR) protein and nine peptides derived from the ETSHR. Peptides were chosen based on their predicted immunogenicity as well as their uniqueness to the TSHR. Antipeptide antibodies showed varying degrees of reactivity against ETSHR, with antipeptide-2-(352-366) and -3A-(357-372) showing relatively stronger reactivity with the receptor. Antibodies were tested for their ability to stimulate thyroid cells and were found to be ineffective in causing both cAMP release and iodide uptake. However, anti-3A and anti-ETSHR showed blocking TSHR antibody (TSHRAb) activities of 76.9% and 79.7%, respectively, which were significantly different (P < 0.005) compared to that of preimmune serum. Anti-2 and -91 (AA 32-46) also showed blocking TSHRAb activities of 37.5% and 35.6%, respectively (P < 0.05). Antisera were also tested for their ability to block TSH binding to thyroid membranes in a RRA. Anti-ETSHR, but not any of the antipeptide antibodies, displayed TSH binding inhibitory immunoglobulin activity. These findings suggest that there might be different mechanisms that mediate blocking TSHR antibody activity. One mechanism involves the inhibition of TSH binding to the receptor, and the other probably involves a step subsequent to TSH binding.

Original languageEnglish (US)
Pages (from-to)658-663
Number of pages6
JournalJournal of Clinical Endocrinology and Metabolism
Volume77
Issue number3
DOIs
StatePublished - Sep 1993
Externally publishedYes

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Endocrinology
  • Clinical Biochemistry
  • Biochemistry, medical

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