The Teplizumab Saga: The Challenge of Not Getting Lost in Clinical Translation.

In November 2022, teplizumab became the first drug approved to delay the course of any autoimmune disease and to change the course of type 1 diabetes (T1D) since the discovery of insulin. The path to its approval took more than 30 years with both successes and failures along the way that would have normally led to its abandonment in other circumstances. Development of the drug was based on studies in preclinical models and parallels efforts in transplantation.

Rebalancing the Immune System to Treat Type 1 Diabetes.

In type 1 diabetes (T1D), the immune system mistakenly attacks the pancreatic islet β cells resulting in the loss of insulin secretion. Insulin-replacement therapy developed more than a century ago provided means to manage the symptoms of diabetes without addressing the root cause of the disease-the faulty immune system. A healthy immune system has built-in mechanisms to limit unwanted, excessive immune activation and prevents damages to self-tissues.

Aire mediates tolerance to insulin through thymic trimming of high-affinity T cell clones.

Insulin is a central autoantigen in the pathogenesis of T1D, and thymic epithelial cell expression of insulin under the control of the Autoimmune Regulator () is thought to be a key component of maintaining tolerance to insulin. In spite of this general working model, direct detection of this thymic selection on insulin-specific T cells has been somewhat elusive. Here, we used a combination of highly sensitive T cell receptor transgenic models for detecting thymic selection and sorting and sequencing of Insulin-specific CD4+ T cells from Aire-deficient mice as a strategy to further define their selection.

Harnessing regulatory T cells to establish immune tolerance.

Engineered regulatory T (T) cells have emerged as precision therapeutics aimed at inducing immune tolerance while reducing the risks associated with generalized immunosuppression. This Viewpoint highlights the opportunities and challenges for engineered T cell therapies in treating autoimmune and other inflammatory diseases.

Opportunities for Treg cell therapy for the treatment of human disease.

Regulatory T (Treg) cells are essential for maintaining peripheral tolerance, preventing autoimmunity, and limiting chronic inflammatory diseases. This small CD4+ T cell population can develop in the thymus and in the peripheral tissues of the immune system through the expression of an epigenetically stabilized transcription factor, FOXP3. Treg cells mediate their tolerogenic effects using multiple modes of action, including the production of inhibitory cytokines, cytokine starvation of T effector (.