G6PC2 and pancreatic insulinoma: However, that study employed NIT-1 (an insulinoma cell line established from the islet beta cells) and 8.3 T-cells (CD8+ T-cells that recognize the IGRP206–214 epitope derived from the islet antigen IGRP (islet-specific glucose-6-phosphatase catalytic subunit-related protein)) as target and effector cells, respectively [32].