This model system can be used for future studies to examine T cells of other specificities such as those responding to glutamic acid decarboxylase (GAD), insulinoma antigen-2 (IA-2), zinc transporter 8, hybrid insulin peptides and neoepitopes, and other immune cell subsets involved in T1D pathogenesis. The gene discussed is PTPRN; the disease is type 1 diabetes mellitus.