ANTIGEN PRESENTATION BY THYMOMA EPITHELIAL-CELLS FROM MYASTHENIA-GRAVIS PATIENTS TO POTENTIALLY PATHOGENIC T-CELLS

Thymomas associate strongly with myasthenia gravis (MG). We now show t hat cultured thymoma epithelial cells can present synthetic acetylchol ine receptor (AChR) peptides to HLA-sharing responder T cell lines/clo nes nearly as efficiently as blood mononuclear cells. Responses depend ed strictly on the specific antigen added. Processing of longer recomb inant AChR polypeptides was clearly less efficient than by blood monon uclear cells, and was selectively abolished by preculture with chloroq uine. The T cell responses depended on the presence of LFA-3 on the th ymoma cells. This study demonstrates that thymoma epithelial cells hav e the capacity to stimulate T cells and perhaps, therefore, to autosen sitize against AChR in vivo.