Review
Thyrotropin-receptor antibodies in thyroid diseases: advances in detection techniques and clinical applications

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Introduction

Thyroid disorders are the most common autoimmune endocrinopathies. Thyroid autoimmunity is complex, involving multiple autoantigens with variable immune responses. Although the topic has been studied extensively, it has been difficult to determine the links between these immune responses and the pathogenesis of thyroid disease. The exception is the Graves’ disease, in which thyrotropin-receptor (TSH-R) antibodies (TRAbs) directly affect TSH-R function and thus play a major role in the pathogenesis of the disease. The TRAbs not only compete with TSH for receptor binding but often mimic TSH and initiate the post-receptor signal transduction process. The heterogeneous nature of TRAbs is well established. Antibodies capable of interacting with multiple epitopes on TSH-R molecule and showing variable TSH activities, both agonistic and antagonistic are generally present in a given patient. This variation in epitope specificity is reflected by the influence of TRAbs on TSH-receptor function.

The clinical role of these antibodies could not be fully understood until the epitopes on TSH-R were identified and their interaction with the TRAbs studied. In recent years, a number of investigators have advanced our understanding of how TSH and TRAbs interact with TSH-R [1], [2], [3], [4] and have led to new molecular technologies to detect TRAbs activities with precision. The purposes of this review are, first, to summarize recent advances in these assay techniques for measuring various TRAb activities, and second, to describe their potential clinical uses.

Before describing the details of the newer assay technologies, it seems appropriate to discuss the molecular structure of TSH-R and its interaction with TSH and TRAbs. The knowledge of these interactions is necessary to understand the mechanisms that lead to signal transduction and the activation of the thyroid cell [5], [6], [7], [8].

Section snippets

TSH-R structure and functional relationships

The TSH-R gene has been cloned and sequenced [9], [10], [11] and has been located on the long arm of chromosome 14q31 [12]. It contains 10 exons spreading over 60 kilobases [13]. Exons 1–9 code for the extracellular domain (ECD) of the receptor, and exon 10 codes for the transmembrane region. Exons 2–8 code for the leucine-rich repeats [9].

By binding to TSH, TSH-R regulates thyroid cell function, differentiation, and proliferation [14]. It belongs to the superfamily of G-protein coupled

Historical perspectives

Beginning in 1956, Adams, Purves and McKezie established that a factor distinct from TSH, which they named the long-acting thyroid stimulator (LATS), was the cause of hyperthyroidism in Graves’ disease [41], [42], [43], [44]. Studies in 1964 found that LATS was an immunoglobulin (IgG) [45], which later become known as thyroid stimulating immunoglobulin or TSAb. The McKenzie bioassay using mice for the detection of LATS activity remained the method of choice until early 1970s. In 1971, Onaya et

Heterogeneity of TRAbs

The heterogeneous nature of TRAbs is well recognized. Many attempts have been made to correlate the two activities of TRAb that are detected by TBI and TSAb assays [107], [108], [109], [110], [111], [112]. Although some reports observed good correlation between TSAb and TBII in Graves’ disease patients [112], most studies have found no such correlation. This disparity between TBII and TSAb results could be related to species specificity, as porcine receptor has been used for most TBII studies

Clinical significance

The clinical utility of TRAbs in routine cost-effective management of patients with thyroid disease has been a subject of controversy for years [119]. The newer simple, precise, and cost-effective methods using CHO-TSHR cells have made it practical to detect TRAbs, and this has enhanced the utility of TRAbs in a number of clinical situations that are summarized in Table 3. These include the differential diagnosis of hyperthyroidism and hypothyroidism, predicting the response to therapy in

Summary

The cloning and sequencing of TSH-R, combined with advances in molecular techniques, have facilitated the development of new refined assays to measure TRAbs. The availability of recombinant human TSH-R for TBI assay and of stable TSH-R-transfected CHO cells for functional assays have encouraged the development of simple, precise, and sensitive tests of the biologic effects of TRAbs on thyroid function. Furthermore, an understanding of the interaction of these antibodies with the TSH-R at the

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References (164)

  • S. Kosugi et al.

    Further characterization of a high affinity thyrotropin binding site on the rat thyrotropin receptor which is an epitope for blocking antibodies from idiopathic myxedema patients but not thyroid stimulating antibodies from Graves’ patients

    Biochem Biophys Res Commun

    (1991)
  • K. Tahara et al.

    Immunoglobulins from Graves’ disease patients interact with different sites on TSH receptor/LH-CG receptor chimeras than either TSH or immunoglobulins from idiopathic myxedema patients

    Biochem Biophys Res Comm

    (1991)
  • M.K. Gupta

    Thyrotropin receptor antibodies: advances and importance of detection techniques in thyroid diseases

    Clin Biochem

    (1992)
  • J. Perret et al.

    Stable expression of the human TSH receptor in CHO cells and characterization of differentially expressing clones

    Biochem Bophys Res Commun

    (1990)
  • B. Rapoport et al.

    Bioassay of TSH using dog thyroid cells in monolayer culture

    Metabolism

    (1978)
  • B. Rapoport et al.

    Studies on the cyclic AMP response to thyroid stimulating immunoglobulin (TSI) and thyrotropin (TSH) in human thyroid cell monolayers

    Metabolism

    (1982)
  • M.R. Kim et al.

    Thyroid stimulating antibody assay using a human thyrotropin receptor transfected cell line: Relationship to clinical features of Graves’ disease

    Endocrine Practice

    (1997)
  • J.C. Morris et al.

    Clinical utility of thyrotropin-receptor antibody assays: Comparison of radioreceptor and bioassay methods

    Mayo Clin Proc

    (1988)
  • M. Ludgate et al.

    Use of the recombinant human thyrotropin receptor (TSH-R) expressed in mammalian cell lines to assay TSH-R autoantibodies

    Mol Cell Endocrinol

    (1990)
  • H.A. Drexhage et al.

    Evidence for thyroid growth-stimulating immunoglobulins in some goitrous thyroid diseases

    Lancet

    (1980)
  • T. Akamizu et al.

    Molecular studies on thyrotropin (TSH) receptor and anti TSH receptor antibodies

    Endocrine J

    (1995)
  • B. Rapoport et al.

    The thyrotropin (TSH) receptor: interaction with TSH and autoantibodies

    Endocrine Rev

    (1998)
  • T. Mori et al.

    Recent progress in TSH receptor studies with a new concept of “autoimmune TSH receptor disease”

    Endocrine J

    (1994)
  • Y. Nagayama et al.

    The thyrotropin receptor twenty five years after its discovery: new insight following its molecular cloning

    Mol Endocrinol

    (1992)
  • Y. Nagayama et al.

    The thyrotropin receptor: Its gene expression and structure-function relationships

    Thyroid Today

    (1994)
  • T. Akamizu et al.

    Molecular studies in thyrotropin (TSH) receptor and anti-TSH receptor antibodies

    Endocrine J

    (1995)
  • M. Parmentier et al.

    Molecular cloning of the thyrotropin receptor

    Science

    (1989)
  • G. Vassart et al.

    The thyrotropin receptor and the regulation of thyrocyte function and growth

    Endocr Rev

    (1992)
  • E.A. Bone et al.

    Norepinephrine and thyroid-stimulating hormone induced inositol phosphate accumulation in FRTL-5 cells

    Endocrinology

    (1986)
  • J.B. Field et al.

    Thyroid-stimulating hormone stimulates increases in inositol phosphates as well as cyclic AMP in FRTL-5 rat thyroid cells

    Biochem J

    (1987)
  • C. Marcocci et al.

    Norepinephrine and thyrotropin stimulation of iodide efflux in FRTL-5 thyroid cells involves metabolites of arachidonic acid and is associated with the iodination of thyroglobulin

    Endocrinology

    (1987)
  • R. Ekholm et al.

    Control of the thyroid: Regulation of its normal growth and function

    Adv Exp Med Biol

    (1989)
  • J. VanSande et al.

    Thyroid stimulating immunoglobulins, like thyrotropin, activate both the cyclic AMP and the PIP2 cascade in CHO cells expressing the TSH receptor

    Mol Cell Endocrinol

    (1992)
  • A. Hidaka et al.

    Receptor cross-talk can optimize assays for autoantibodies to the thyrotropin receptor: Effect of phenylisopropyladenosien on adenosine 3′,5′-monophosphate and inositol phosphate levels in rat FRTL-5 thyroid cells

    J Clin Endocrinol Metab

    (1993)
  • F. Libert et al.

    Thyroperoxidase, but not the thyrotropin receptor, contains sequential epitopes recognized by autoantibodies in recombinant peptides expressed in the pUEX vector

    J Clin Endocrinol Metab

    (1991)
  • H. Vlase et al.

    Human autoantibodies to the thyrotropin receptor: recognition of linear, folded, and glycosylated recombinant extracellular domain

    J Clin Endocrinol Metab

    (1995)
  • G.S. Seetharamaiah et al.

    Requirement of glycosylation of the human thyrotropin receptor ectodomain for its reactivity with autoantibodies in patients’ sera

    J Immunol

    (1997)
  • W.P. Bryant et al.

    Identification of thyroid blocking antibodies and receptor epitopes in autoimmune hypothyroidism by affinity purification using synthetic TSH receptor peptides

    Autoimmunity

    (1995)
  • S. Kosugi et al.

    The extracellular domain of the TSH receptor has an immunogenic epitope reactive with Graves’ IgG but unrelated to recptor function as well as determinants having different roles for high affinity TSH bindings and the activity of thyroid-stimulating antibodies

    Thyroid

    (1991)
  • E.V. Nagy et al.

    Immunogenicity of a unique region of the human thyrotropin receptor

    J Endocrinol Invest

    (1993)
  • S. Kosugi et al.

    Identification of separate determinants on the thyrotropin receptor reactive with Graves’ thyroid stimulating antibodies and with thyroid stimulating blocking antibodies in idiopathic myxedema: these determinants have no homologous sequence on gonadotropin receptors

    Mol Endocrinol

    (1992)
  • S. Kosugi et al.

    Identification of thyroid stimulating antibody-specific interaction sites in the N-terminal region of the thyrotropin receptor

    Mol Endocrinol

    (1993)
  • Y. Nagayama et al.

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

    J Clin Invest

    (1991)
  • A. Hidaka et al.

    Thyrotropinstimulation of the lutropin/choriogonadotropin receptor: different sites mediate agonist activity and high affinity binding

    Thyroid

    (1994)
  • W.B. Kim et al.

    Epitopes for thyroid st imulating antibodies Graves’ sera: a possible link of heterogeneity to differences in response to antithyroid drug treatment

    J Clin Endocrinol Metab

    (1996)
  • W.B. Kim et al.

    Changes in epitopes for thyroid-stimulating antibodies in Graves’ disease sera during treatment of hyperthyroidism: therapeutic implications

    J Clin Endocrinol Metab

    (1997)
  • T. Akamizu et al.

    Further studies of amino acids (268–304) in thyrotropin (TSH)-lutropin/chorionic gonadotropin (LH/CG)receptor chimeras: cysteine-301 is important in TSH binding and receptor tertiary structure

    Thyroid

    (1994)
  • K. Tahara et al.

    Epitopes for thyroid stimulating and blocking autoantibodies on the extracellular domain of the human thyrotropin receptor

    Thyroid

    (1997)
  • D.D. Adams et al.

    Abnormal responses in the assay of thyrotropin

    Proc Univ Otago Med Sch

    (1956)
  • D.D. Adams

    The presence of an abnormal thyroid-stimulating hormone in the serum of some thyrotoxic patients

    J Clin Endocrinol Metab

    (1958)

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