Dr. Herold was trained as an Endocrinologist and Immunologist. After his training he went to the Hagedorn Research Laboratory in Denmark, and then he joined the faculty at The University of Chicago. He moved to New York to Columbia and in 2006 to Yale University. He has built a program in translational immunology applying mechanistic discoveries to treat autoimmune diseases, including Type 1 diabetes (T1D). He brought teplizumab, the first drug approved by the FDA to treat the underlying cause of T1D from mice to humans. He showed that brief treatment with teplizumab, which is a humanized FcR non-binding anti-CD3 mAb could reduce beta cell killing without continuous immune suppression and improved clinical outcomes in patients with T1D. He led studies leading to approval of the drug in the US and Europe. It is the first drug to prevent any autoimmune disease. His studies bridge immunology, cell biology and metabolism and identified relationships between immune and endocrine cells. He identified how beta cells adapt to and survive immune attack and developed an assay to measure their death in vivo. He described autoimmune diabetes induced by anti-PD-1/L1 checkpoint inhibitors in patients with cancers, and its mechanisms. He identified mechanisms that can prevent killing of beta cells by inflammatory mediators. This work is leading to the development of replacement beta cells for patients with diabetes. He is the former Chair of NIDDK TrialNet, the premier network for testing therapies to prevent T1D.  He was awarded the Watanabe prize in 2025.