ISLET-SPECIFIC T-CELL CLONES FROM THE NOD MOUSE RESPOND TO BETA-GRANULE ANTIGEN

Islet-reactive T-cell clones from NOD mice provide an important approa ch to the investigation of antigens with relevance to type I diabetes. To identify a source of beta-cell antigen suitable for biochemical st udies, we have used two islet-specific, diabetogenic T-cell clones to test beta-tumor cells. beta-tumor cell lines, maintained in continuous culture, were found to lose antigenicity rapidly. However, cells harv ested directly from beta-tumors arising spontaneously in the transgeni c NOD/Lt-Tg(RIPTag)1Lt mouse proved to be a potent source of beta-cell antigen for the T-cell clones. Subcellular fractionation of beta-tumo r cells showed that the T-cell antigen was highly enriched in the beta -granule fraction and that this activity was associated with the granu le membrane.