Type 1 diabetes (T1D) is a T cell-mediated autoimmune disease resulting in the destruction of pancreatic beta-cells. Infiltrating leukocytes generate an inflammatory environment consisting of reactive oxygen species (ROS) and proinflammatory cytokines that collectively participate in beta-cell destruction and enhance the adaptive immune effector response of islet-specific T cells. Environmental factors that include viral infections are hypothesized to directly lyse pancreatic beta-cells and generate a pro-inflammatory milieu necessary to enhance T cell autoreactivity. Currently, a gap exists in our understanding of why the immune system attacks itself in Type 1 diabetics and the signals involved in initiating immune system activation in T1D. Our previous work has demonstrated the importance of oxidative stress and the generation of ROS as essential to the pathogenesis of T1D. ROS production is required for autoimmune responses during the development of T1D in Non-Obese Diabetic (NOD) mice, a mouse model that is widely used to study T1D. Mice deficient in superoxide synthesis (NOD.Ncf1m1J) are resistant to the development of T1D and our proposed studies to further define the synergy of ROS on immune responses have the potential to provide novel insight on the mechanisms associated with pancreatic â-cell destruction in T1D. Our proposed studies will test the hypothesis that ROS synthesis is necessary for efficient anti-viral responses in T1D. Specifically, we will define the role of redox-dependent signals involved in the activation of human innate immune receptors such as Toll-like receptor 3 (TLR3), melanoma differentiation-associated gene 5 (MDA5), and retinoic acid-inducible gene I (RIG-I) in response to Coxsackie virus infection with PBMCs from recent onset T1D and healthy patients. The studies in this proposal will further expand our knowledge of how innate immune-derived pro-inflammatory signals synergize to mediate efficient autoreactive T cell responses in Type 1 diabetes.