Effects of TSH receptor mutations on binding and biological activity of monoclonal antibodies and TSH
| Autor: | Sara Summerhayes, Bernard Rees Smith, Jane Sanders, Jane Bolton, Tonya Richards, Jadwiga Furmaniak, Angela Kiddie, Michele Evans, Nobuhiro Nakatake, Paul W. Sanders, Emma Roberts, Ricardo Núñez Miguel, Jennifer Jeffreys |
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| Rok vydání: | 2007 |
| Předmět: |
Models
Molecular endocrine system endocrine system diseases medicine.drug_class Endocrinology Diabetes and Metabolism Thyrotropin Stimulation CHO Cells Biology Monoclonal antibody Transfection Epitope Antigen-Antibody Reactions Mice Endocrinology Cricetulus Cricetinae medicine Cyclic AMP Animals Humans Point Mutation Receptor chemistry.chemical_classification Chinese hamster ovary cell Antibodies Monoclonal Biological activity Receptors Thyrotropin Graves Disease Amino acid Protein Structure Tertiary Biochemistry chemistry biology.protein Antibody |
| Zdroj: | Thyroid : official journal of the American Thyroid Association. 16(12) |
| ISSN: | 1050-7256 |
| Popis: | The effects of an extensive series of mutations in the TSH receptor (TSHR) leucine-rich domain (LRD) on the ability of thyroid-stimulating monoclonal antibodies (TSMAbs) and TSH to bind to the receptor and stimulate cyclic AMP production in TSHR-transfected CHO cells has been investigated. In addition, the ability of a mouse monoclonal antibody with blocking (i.e., antagonist) activity (RSR-B2) to interact with mutated receptors has been studied. Several amino acids distributed along an extensive part of the concave surface of the LRD were found to be important for binding and stimulation by the thyroid-stimulating human MAb M22 but did not appear to be important for TSH binding and stimulation. Most of these amino acids important for M22 interactions were also found to be important for the stimulating activity of six different mouse TSMAbs and a hamster TSMAb. Furthermore, most of these same amino acids were important for stimulation by TSHR autoantibodies in a panel of sera from patients with Graves' disease. Amino acid R255 was the only residue found to be unimportant for TSH stimulation but critical for stimulation by all thyroid-stimulating antibodies tested (23 patient serum TSHR autoantibodies, M22, and all seven animal TSMAbs). About half the amino acids (all located in the N-terminal part of the LRD) found to be important for M22 activity were also important for the blocking activity of RSR-B2 and although the epitopes for the two MAbs overlap they are different. As the two MAbs have similar affinities, their epitope differences are probably responsible for their different activities. Overall our results indicate that different TSMAbs and different patient sera thyroid-stimulating autoantibodies interact with the same region of the TSHR, but there are subtle differences in the actual amino acids that make contact with the different stimulators. |
| Databáze: | OpenAIRE |
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