Antibodies specific for human thyrotropin receptor induce MHC antigen expression in thyroid cells.

Autoantibodies (AAbs) to hormone receptors are found in autoimmune diseases such as Graves' disease (GD) or myasthenia gravis. A structural link between hormone receptor and MHC genes has been documented, suggesting a possible co-regulation of MHC and hormone receptor genes. Thus, in vitro experiments were designed to search for a pathologic role for AAbs. In a model study, we investigated whether adding murine anti-human thyrotropin receptor mAbs would affect MHC gene expression in either cloned human thyroid epithelial cell or primary murine thyroid epithelial cell cultures. We found that two anti-human thyrotropin receptor monoclonal AAbs, 11E7 and 34A, induced, with an intensity comparable to that of IFN-gamma, transcription and expression of class I and class II/Ii chain proteins in human and murine thyroid epithelial cells. Two other anti-human thyrotropin receptor mAbs, 12E3 and 243-3, were ineffective. These data suggest a new role for autoantibodies in the pathology of autoimmune endocrinopathies.