The primary purpose of this solicitation is to support highly interactive, multi-disciplinary teams whose research efforts are focused on large-scale discovery of T cell immune epitopes associated with infectious or autoimmune diseases, commensal organisms, or alloantigens influencing transplant outcomes, and validation of these epitopes, and defined mechanisms of T cell immune protection or immune-mediated pathogenesis in humans. Investigators may also include development/refinement of T cell epitope prediction tools as part of their research plan. It is anticipated that the multi-disciplinary teams will minimally include immunologists with the appropriate expertise in epitope identification and validation, and either microbiologists and/or virologists with expertise in the target pathogen(s), or clinicians with expertise in the target autoimmune disease(s) or transplantation immunology, as appropriate. This program will not support studies related to HIV/AIDS or allergen epitopes.