TCR-Based Antigen-Specific Therapy for Type 1 Diabetes Mellitus: From Editing Autoreactive Clones to Tolerance Induction

Type 1 diabetes mellitus (T1DM) is an autoimmune disease caused by the destruction of insulin-producing pancreatic β-cells by autoreactive T cells. Current treatments, including insulin replacement therapy and various immunotherapies, often modulate but fail to permanently halt the underlying autoimmune process or restore β-cell function. In this review, we examine T cell receptor (TCR)-based treatment strategies for T1DM. We focus on two main approaches: selective elimination of pathogenic autoreactive T cell clones and induction of immune tolerance using TCR-modified regulatory T cells (TCR-Tregs). We describe key islet autoantigens, including post-translationally modified neoantigens such as fusion insulin peptides, which are crucial for identifying pathogenic TCRs. Next, we will review methodologies for TCR detection and TCR-Treg generation, highlighting their mechanisms of action and impact on various immune cells, including dendritic cells, B cells, and macrophages. We will also examine the potential of CD8⁺T cell regulatory cells (CD8⁺Tregs). Finally, we will discuss the future of TCR-based therapy, emphasizing the need to optimize TCR affinity, ensure Tregs’ stability, and develop combination therapies. TCR-based therapy represents a revolutionary approach to restoring immune tolerance in T1DM, providing high specificity and reducing the risk of systemic immuno-suppression compared to traditional treatments.