The Hsieh laboratory is interested in understanding the mechanisms that lead to immune tolerance to both self-antigens involved in autoimmune disease, as well as non-self-antigens from antigens that come from the environment such as commensal bacteria or food. We utilize TCR repertoire analysis and germ-free mice to study T cell tolerance. A better understanding of how the immune system develops tolerance may be relevant for understanding autoimmune disease, food allergy, and inflammatory bowel disease.