IDENTIFICATION OF THYROID-STIMULATING HORMONE RECEPTOR-SPECIFIC T-CELLS IN GRAVES-DISEASE THYROID USING AUTOANTIGEN-TRANSFECTED EPSTEIN-BARR VIRUS-TRANSFORMED B-CELL LINES

The importance of thyrotropin receptor (TSHR) agonist antibodies in th e manifestations of Graves' disease (GD) is recognized. There are, how ever, no convincing reports of TSHR-specific T cells. We have previous ly cloned T cells specific for thyroglobulin and thyroid peroxidase (T PO) from GD lymphoid infiltrates and used autologous EBV-transformed B cell lines (EBVL) transfected with an expression vector encoding TPO to efficiently detect TPO-specific T cells. Here we used EBVL transfec ted with TSHR to seek TSHR-specific T cells in the GD infiltrates, aft er cloning the in vivo activated T cells without antigen, 3 out of 30 clones responded vigorously and reproducibly to EBVL-TSHR, with a mean stimulation index > 7, Their release of IL-2, IL-4, and IL-10 after s timulation with soluble anti-CD3 and phorbol ester was indistinguishab le from the other clones from this thyroid. However, they produced rel atively little IFN gamma (median IL-4/IFN gamma ratio of 0.80) compare d with the other clones (median IL-4/IFN gamma ratio 0.06). Thus, this new potent method of antigen presentation, using autoantigen-transfec ted EBVL, has permitted the first unequivocal identification of TSHR T cells in GD thyroid, with distinct Th0/ Th2 characteristics, unlike p reviously cloned TPO-responsive cells which have Th1 characteristics.