Self-reactive cytotoxic gamma delta T lymphocytes in Graves' disease specifically recognize thyroid epithelial cells'

In this paper we report the isolation of a self-reactive cytotoxic gamma delta T cell line, 158RE.2, that originates from the T lymphocyte population infiltrating the thyroid gland of a patient with Graves' disease. Functional data using this cell line demonstrate that gamma delta T cells expanded in the thyroid tissue specifically recognize a ligand expressed by thyroid epithelial cells and cell lines of endocrine epithelial origin, The TCR expressed by these gamma delta T cells-V gamma 1/V delta 5-is unusual in peripheral blood lymphocytes, and its specificity is clearly different from that observed in a high percentage of gamma delta T cells from PBL, which express the common TCR V gamma 9/V delta 2, The V gamma 1/V gamma 5 receptor is involved in the recognition of the ligand expressed by the thyroid cells, but not in the NK-like activity also displayed by 158RE.2, These cells express CD8 alpha alpha dimers, which participate in the thyroid ligand recognition but not in the NK-like activity, The epithelial cell recognition is not restricted by classical MHC class I or class II molecules, although the CD8 alpha alpha participation in the recognition suggests the involvement of nonclassical MHC molecules, These are the first data to be presented on self-reacting gamma delta T cells in human epithelium.