Insulin β Chain Peptide (15-23), also known as INS, is an insulin-derived peptide recognized by islet-associated T cells. The Insulin β Chain Peptide (15-23) tetramer stained the INS-reactive CTL clone G9C8, but neither this tetramer nor the negative control tetramer (TUM) stained the splenic CD8+ T cells from NOD or 8.3-TCRαβtransgenic NOD mice.