Thyroid-Stimulating Monoclonal Antibodies

Abstract

Thyrotropin (TSH) receptor monoclonal antibodies (TSHR mAbs) were obtained from cDNA-immunized NMRI mice. Three mAb immunoglobulin Gs (IgGs) (TSmAbs 1-3) that had distinct V(H )and V(L) region sequences stimulated cyclic adenosine monophosphate (cAMP) production in isolated porcine thyroid cells greater than 10x basal and as little as 20 ng/mL (0.13 nmol/L) of TSmAb 1 IgG caused a 2x basal stimulation. TSmAb 1 and 2 Fab fragments were also effective stimulators and thyroid-stimulating activities of the IgGs and Fabs were confirmed using TSHR transfected Chinese hamster ovary (CHO) cells. The TSmAbs also inhibited (125)I-labeled TSH binding to TSHR-coated tubes by 50% or more at concentrations of 1 microg/mL or less and gave 15%-20% inhibition at 20-50 ng/mL. (125)I-labeled TSmAbs bound to TSHR-coated tubes with high affinity (approximately 10(10) L/mol) and this binding was inhibited by TSHR autoantibodies with both TSH agonist and antagonist activities. Inhibition of labeled TSmAb binding by Graves' sera correlated well with inhibition of TSH binding (r = 0.96; n = 18; p < 0.001 for TSmAb 2). The TSmAbs have considerable potential as (1) new probes for TSHR structure-function studies, (2) reagents for new assays for TSHR autoantibodies, and (3) alternatives to recombinant TSH in various in vivo applications.

Yersinia enterocolitica Provides the Link between Thyroid-Stimulating Antibodies and Their Germline Counterparts in Graves’ Disease

“…This finding of restricted L chain usage for TSAb activity after SHM events suggests that agonistic activity to the TSHR is mediated by a particular conformation of Ab that can perhaps be attained by a few combinations of IGH and IGK rearrangements. These observations are in line with tentative findings on the common usage of certain gene rearrangements in monoclonal TSAbs from experimental Graves' disease (7,8,30) and the human monoclonal TSAbs from patients with autoimmune hyperthyroidism (11,12). Although limited information is available, there appears to be notable similarity in the gene usage by mouse and human monoclonal TSAbs (Supplemental Table I).…”

“…Recent genetic studies in inbred mice strains have implicated the IGH V region gene locus in TSAb development (5,6). Monoclonal TSAbs with powerful agonist activity have been characterized from mice undergoing experimental Graves' disease following immunization by genetic delivery of plasmid or adenovirus encoding TSHR or the extracellular region of the receptor, known as TSHR A-subunit (7)(8)(9). The monoclonal TSAbs derived from experimental models of Graves' disease have been shown to be pathogenic in vivo, confirming their role in disease pathogenesis (8)(9)(10).…”

Evaluation of a 1 step TRAb Assay for the Detection of High-affinity Components to hTSHR: Evidences Indicating Superiority of the Assay in the Lower TRAb Range

“…We have studied TRAb actions to TSHR in detail, and reported that there are rapidacting and slow-acting components among TRAb [18]. Recently, high-affinity mouse monoclonal TRAb antibodies (mAb) were produced by 3 research groups [25][26][27]. These mAb are quite useful for understanding Graves' hyperthyroidism, and developing new TRAb assays [28].…”

TNFα mediates the skeletal effects of thyroid-stimulating hormone

“…Cells in bone marrow were examined by flow cytometry using PE (phycoerythrin)-labeled CD11b, CD3, B220, CD90, CD45, CD4, and CD8 antibodies (PharMingen, San Diego, CA). TSHR expression was also detected by using RSR-1 (kindly provided by Bernard R. Smith; RSR Ltd., Cardiff, U.K.) (34) or MS-1 (15) antibodies. To avoid the binding of antibodies to Fc receptor, cells were preincubated with guinea pig serum and then incubated with TSHR antibodies or nonimmune IgG (isotype control).…”