ANTIBODIES SPECIFIC FOR HUMAN THYROTROPIN RECEPTOR INDUCE MHC ANTIGENEXPRESSION IN THYROID-CELLS

Autoantibodies (AAbs) to hormone receptors are found in autoimmune dis eases such as Graves' disease (GD) or myasthenia gravis. A structural link between hormone receptor and MHC genes has been documented, sugge sting a possible co-regulation of MHC and hormone receptor genes. Thus , in vitro experiments were designed to search for a pathologic role f or AAbs. In a model study, we investigated whether adding murine anti- human thyrotropin receptor mAbs would affect MHC gene expression in ei ther cloned human thyroid epithelial cell or primary murine thyroid ep ithelial cell cultures. We found that two anti-human thyrotropin recep tor monoclonal AAbs, 11E7 and 34A, induced, with an intensity comparab le to that of IFN-gamma, transcription and expression of class I and c lass II/li 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.