A water-soluble fragment of the thyroid-stimulating hormone receptor which binds both thyroid-stimulating hormone and thyroid-stimulating hormone receptor antibodies

1984 ◽  
Vol 100 (1) ◽  
pp. 113-118 ◽  
Author(s):  
E. Davies Jones ◽  
B. Rees Smith
Keyword(s):  
Hormone Receptor ◽  
Gel Filtration ◽  
Thyroid Stimulating Hormone ◽  
Water Soluble ◽  
Tsh Receptor ◽  
Human Thyroid ◽  
Freezing And Thawing ◽  
Receptor Antibodies ◽  
Tsh Receptor Antibodies ◽  
Stimulating Hormone

ABSTRACT Previous studies have shown that freezing and thawing of human thyroid homogenates releases a water-soluble substance which reversibly binds to TSH-receptor antibodies. This substance has been designated long-acting thyroid stimulator absorbing activity (LAA). We now describe a new method for measuring LAA based on the TSH-receptor assay and application of the technique to the study of LAA. Our results indicate that LAA is a heat-labile glycoprotein which co-elutes with haemoglobin on gel filtration. Furthermore, LAA is retarded by columns of Sepharose–TSH but not by Sepharose coupled to human chorionic gonadotrophin, normal immunoglobulin G or bovine serum albumin, suggesting that LAA contains a binding site for TSH as well as for TSH-receptor antibodies. It would seem therefore that LAA is a water-soluble fragment of the TSH receptor possibly resulting from proteolytic cleavage of the receptor at a site close to the cell surface. J. Endocr. (1984) 100, 113–118

scholarly journals Interaction of autoantibodies to thyrotropin receptor with a hydrophilic subunit of the thyrotropin receptor

1985 ◽  
Vol 228 (1) ◽  
pp. 111-117 ◽  
Author(s):  
E Davies Jones ◽  
F A Hashim ◽  
Y Kajita ◽  
F M Creagh ◽  
P R Buckland ◽  
...  
Keyword(s):  
Gradient Centrifugation ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Water Soluble ◽  
Tsh Receptor ◽  
Human Thyroid ◽  
Thyrotropin Receptor ◽  
Freezing And Thawing ◽  
Sucrose Density Gradient Centrifugation ◽  
A Subunit

Reduction of human thyroid membranes with dithiothreitol caused the release of a water-soluble glycoprotein which neutralized the thyrotropin (TSH) receptor-binding and thyroid-stimulating activities of Graves‘ serum. Analysis of the protein by gel filtration and sucrose density gradient centrifugation allowed estimates of 3.45 nm for the Stokes’ radius, 3.6 S for the s20,w and 47 000 +/- 5000 (mean +/- S.D.; n = 4) for the Mr. The material released by dithiothreitol treatment could be crosslinked to 125I-labelled TSH coupled to N-hydroxysuccinimidyl 4-azidobenzoate (125I-HSAB-TSH), suggesting that it contained a component of the TSH receptor. Furthermore, analysis of the crosslinked material by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis indicated that it contained the TSH receptor A subunit (Mr 50 000). Several factors suggested therefore that the glycoprotein released by dithiothreitol treatment of human thyroid membranes was the TSH receptor A subunit. In particular, (a) both preparations were hydrophilic and were released from membranes by reduction, (b) they had similar Mr values and (c) both preparations crosslinked to 125I-HSAB-TSH. Material similar to the TSH receptor A subunit was released from thyroid membranes by treatment with papain, probably as a result of cleavage of the receptor A subunit at a site close to the interchain disulphide bridge. A similar mechanism, involving thyroid proteinases, was probably involved in release of material with similar properties to the TSH receptor A subunit during freezing and thawing of human thyroid homogenates.

scholarly journals Hipotiroidismo Associado a Anticorpos Anti-Receptor da Hormona TSH com Ação Bloqueadora Determinada In Vitro

2015 ◽  
Vol 28 (5) ◽  
pp. 663
Author(s):  
Pedro Marques ◽  
Karim Chikh ◽  
Anne Charrié ◽  
Rosa Pina ◽  
Maria João Bugalho ◽  
...  
Keyword(s):  
Hormone Receptor ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Thyroid Stimulating Hormone ◽  
Human Thyroid ◽  
In Vitro Tests ◽  
Lymphocytic Thyroiditis ◽  
Blocking Activity ◽  
Stimulating Hormone

Thyroid-stimulating hormone-receptor autoantibodies normally causes hyperthyroidism. However, they might have blocking activity causing hypothyroidism. A 11-year-old girl followed due to type 1 diabetes mellitus, celiac disease and euthyroid lymphocytic thyroiditis at diagnosis. Two years after the initial evaluation, thyroid-stimulating hormone was suppressed with normal free T4; nine months later, a biochemical evolution to hypothyroidism with thyroid-stimulating hormone-receptor autoantibodies elevation was seen; the patient remained always asymptomatic. Chinese hamster ovary cells were transfected with the recombinant human thyroid-stimulating hormone -receptor, and then exposed to the patient´s serum; it was estimated a ‘moderate’ blocking activity of these thyroid-stimulating hormone-receptor autoantibodies, and concomitantly excluded stimulating action. In this case, the acknowledgment of the blocking activity of the serum thyroid-stimulating hormone-receptor autoantibodies, supported the hypothesis of a multifactorial aetiology of the hypothyroidism, which in the absence of the in vitro tests, we would consider only as a consequence of the destructive process associated to lymphocytic thyroiditis.

Anti-TSH receptor antibodies in Graves' disease modulate the kinetic behaviour of autologous thyroid TSH receptors. Evidence of the IgG-induced cross-linkage of autologous TSH receptors

1984 ◽  
Vol 105 (3) ◽  
pp. 330-340 ◽  
Author(s):  
Tjerk W. A. de Bruin ◽  
Daan van der Heide ◽  
Maria C. Krol
Keyword(s):  
Binding Sites ◽  
Plasma Membranes ◽  
Tsh Receptor ◽  
Human Thyroid ◽  
Graves Disease ◽  
Kinetic Behaviour ◽  
High Affinity ◽  
Cross Linkage ◽  
Receptor Antibodies ◽  
Tsh Receptor Antibodies

Abstract. The effect of the anti-TSH receptor antibodies present in the sera of 8 patients with Graves' disease on the affinity constant (Ka) and the number (R) of TSH receptors in autologous human thyroid plasma membranes was investigated. Kinetic analysis of [125I]bTSH binding to human thyroid plasma membranes in the presence of autologous Graves' and normal gammaglobulins was carried out by means of a computer fitting programme. Analysis of the TSH-TSH receptor interaction in the presence of TSH alone yielded curvilinear Scatchard plots, indicating the existence of two independent classes of binding sites (high affinity Ka: 8.5 ± 4.8 × 108 m−1; low affinity Ka: 5.3 ± 2.7 × 106 m−1). Similarly the Scatchard plot for this interaction in the presence of normal gammaglobulins is also curvilinear. Linear Scatchard plots, indicating the existence of only one class of high affinity TSH binding sites (Ka: 3.5 ± 1.8 × 108 m−1), were obtained for both autologous gammaglobulins and pure IgG from 8 patients with Graves' disease. The number of high affinity TSH binding sites in the presence of Graves' gammaglobulins had increased on the average by a factor 3.76 ± 0.74 (sd) with respect to the number found in the presence of normal gammaglobulins. This marked change in the kinetic behaviour of the TSH binding sites provided evidence that there is a direct interaction between anti-TSH receptor antibodies and autologous TSH receptors. Divalency of Graves' IgG or linkage of Fab fragments by anti-Fab antiserum proved to be necessary to produce this specific change in the kinetic behaviour of TSH binding sites. Graves' IgG monovalent Fab and Fc fragments had no effect. We suggest that the mechanism by which anti-TSH receptor antibodies in Graves' disease mimick the biological action of TSH is the IgG-induced cross-linkage of TSH receptors.

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