FIG. 2.

Role of ROS in dendritic cell function and cross-presentation of autoantigen. Dendritic cells pick up beta cell antigen, process in phagosome and lysosomes, assembly with MHC class I in lysosome, and cross-present to CD8. ROS from NADPH oxidase keep the neutral environment in lysosome and are important for enzyme activities in antigen processing and cross-presentation. CD8⁺ T cells recognize beta cell antigens presented by MHC class I. MHP in CD8⁺ T cells also leads to lower ATP production and increased ROS generation. ROS further stimulate calcium flux and facilitate TCR signaling, which results in activation of transcription factors and production of inflammatory cytokines, perforin, granzyme B, and FASL that are all cytotoxic to beta cells. ATP, adenosine triphosphate; MHP, mitochondrial inner membrane hyperpolarization; TCR, T cell receptor.