Epitope mapping of tsh receptor-blocking antibodies in Graves' disease that appear during pregnancy.

Spontaneous remission of Graves' disease during pregnancy is thought to be due to a reduction of thyroid-stimulating antibody activity. We suspected, however, that a broader change in TSH receptor antibody characteristics might play an important role in modulating disease activity during pregnancy. We measured TSH binding inhibitory Ig, thyroid-stimulating antibody, and thyroid stimulating-blocking antibody activities in 13 pregnant Graves' disease patients at first, second, and third trimesters and 4 months postpartum. To measure and epitope-map thyroid-stimulating antibody and thyroid stimulating-blocking antibody activities, we used CHO cells transfected with wild-type human TSH receptor or with several TSH receptor-LH/hCG receptor chimeras: Mc1+2, Mc2, and Mc4. These chimeric cells have their respective TSH receptor residues 9-165, 90-165, and 261-370 substituted with equivalent residues of the LH/hCG receptor. Overall thyroid-stimulating antibody decreased, whereas thyroid stimulating-blocking antibody increased progressively during pregnancy. TSH binding inhibitory Ig fluctuated in individual patients, but overall the activities remained statistically unchanged. Thyroid stimulating-blocking antibody appeared in subjects who were either negative for thyroid-stimulating antibody or whose thyroid-stimulating antibody activity increased or decreased during pregnancy. Epitope mapping showed that the thyroid-stimulating antibodies were mainly directed against residues 9-165 of the N-terminus of the TSH receptor extracellular domain. All thyroid stimulating-blocking antibodies had blocking activities against residues 261-370 of the C-terminus of the ectodomain. However, the majority of the thyroid stimulating-blocking antibodies had a hybrid conformational epitope directed against N-terminal residues 9-89 or 90-165 as well. Despite a change in the activity level, we did not observe any change in the epitope of either the stimulatory or blocking Abs as pregnancy advanced. In conclusion, a change in the specificity of TSH receptor antibody from stimulatory to blocking activity was observed during pregnancy, and the appearance of thyroid stimulating-blocking antibody may contribute to the remission of Graves' disease during pregnancy.

[1]  A. Kung,et al.  Characterization of thyroid-stimulating blocking antibodies that appeared during transient hypothyroidism after radioactive iodine therapy. , 2000, Thyroid : official journal of the American Thyroid Association.

[2]  J. Kwok,et al.  Changes in cytokine production during pregnancy in patients with Graves' disease. , 2000, Thyroid : official journal of the American Thyroid Association.

[3]  B. Prabhakar,et al.  Induction of experimental autoimmune Graves' disease in BALB/c mice. , 1999, Journal of immunology.

[4]  A. Weetman,et al.  The immunology of pregnancy. , 1999, Thyroid : official journal of the American Thyroid Association.

[5]  B. Rapoport,et al.  The Thyrotropin (TSH)-Releasing Hormone Receptor: Interaction with TSH and Autoantibodies , 1998 .

[6]  A. Kung,et al.  A change from stimulatory to blocking antibody activity in Graves' disease during pregnancy. , 1998, The Journal of clinical endocrinology and metabolism.

[7]  N. Ishikawa,et al.  Epitopes for thyroid stimulating and blocking autoantibodies on the extracellular domain of the human thyrotropin receptor. , 1997, Thyroid : official journal of the American Thyroid Association.

[8]  C. Marcocci,et al.  Characterization of monoclonal thyroid-stimulating and thyrotropin binding-inhibiting autoantibodies from a Hashimoto's patient whose children had intrauterine and neonatal thyroid disease. , 1997, The Journal of clinical endocrinology and metabolism.

[9]  H. K. Lee,et al.  Changes in epitopes for thyroid-stimulating antibodies in Graves' disease sera during treatment of hyperthyroidism: therapeutic implications. , 1997, The Journal of clinical endocrinology and metabolism.

[10]  N. Amino,et al.  Subtypes of anti-TSH receptor antibodies classified by various assays using CHO cells expressing wild-type or chimeric human TSH receptor. , 1997, Thyroid : official journal of the American Thyroid Association.

[11]  Y. Kohno,et al.  Induction of Graves-like disease in mice by immunization with fibroblasts transfected with the thyrotropin receptor and a class II molecule. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[12]  M. Yamada,et al.  Discrete characteristics of antibodies raised against thyrotropin receptor-related peptides whose sequences are not conserved in the luteinizing hormone/chorionic gonadotropin receptor. , 1996, The Journal of clinical endocrinology and metabolism.

[13]  H. K. Lee,et al.  Epitopes for thyroid-stimulating antibodies in Graves' sera: a possible link of heterogeneity to differences in response to antithyroid drug treatment. , 1996, The Journal of clinical endocrinology and metabolism.

[14]  T. Akamizu,et al.  Presence of heterogeneous thyroid-stimulating antibodies in sera from individual Graves' patients as shown by synthesized thyrotropin receptor peptide application: evidence showing two independent epitopes and a possible recognition of two epitopic regions by one antibody molecule. , 1995, European journal of endocrinology.

[15]  B. Prabhakar,et al.  Thyrotropin receptor-specific antibodies in BALB/cJ mice with experimental hyperthyroxinemia show a restricted binding specificity and belong to the immunoglobulin G1 subclass. , 1995, Endocrinology.

[16]  T. Akamizu,et al.  Thyroid-stimulating antibodies in sera from patients with Graves' disease are heterogeneous in epitope recognition. , 1995, European journal of endocrinology.

[17]  J. Morris,et al.  Structure-function studies of the human thyrotropin receptor. Inhibition of binding of labeled thyrotropin (TSH) by synthetic human TSH receptor peptides. , 1993, The Journal of biological chemistry.

[18]  L. Kohn,et al.  Identification of thyroid-stimulating antibody-specific interaction sites in the N-terminal region of the thyrotropin receptor. , 1993, Molecular endocrinology.

[19]  B. Rapoport,et al.  Thyroid stimulatory autoantibodies in different patients with autoimmune thyroid disease do not all recognize the same components of the human thyrotropin receptor: selective role of receptor amino acids Ser25-Glu30. , 1992, The Journal of clinical endocrinology and metabolism.

[20]  O. Sadeh,et al.  Changes in stimulating and blocking TSH receptor antibodies in a patient undergoing three cycles of transition from hypo to hyper‐thyroidism and back to hypothyroidism , 1992, Clinical endocrinology.

[21]  T. Akamizu,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. , 1992, Molecular endocrinology.

[22]  T. Minegishi,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. , 1991, Biochemical and biophysical research communications.

[23]  H. Imura,et al.  A synthetic oligopeptide derived from human thyrotropin receptor sequence binds to Graves' immunoglobulin and inhibits thyroid stimulating antibody activity but lacks interactions with TSH. , 1991, Biochemical and biophysical research communications.

[24]  D. Russo,et al.  Binding domains of stimulatory and inhibitory thyrotropin (TSH) receptor autoantibodies determined with chimeric TSH-lutropin/chorionic gonadotropin receptors. , 1991, The Journal of clinical investigation.

[25]  D. Russo,et al.  Thyrotropin-luteinizing hormone/chorionic gonadotropin receptor extracellular domain chimeras as probes for thyrotropin receptor function. , 1991, Proceedings of the National Academy of Sciences of the United States of America.

[26]  M. Murakami,et al.  Identification of immunogenic regions in human thyrotropin receptor for immunoglobulin G of patients with Graves' disease. , 1990, Biochemical and biophysical research communications.

[27]  Rosalind S. Brown,et al.  Maternal thyroid-blocking immunoglobulins in congenital hypothyroidism. , 1990, The Journal of clinical endocrinology and metabolism.