Project Summary We propose to develop a new immunogenicity assay and machine learning based framework for creating tolerization vaccines for autoimmune diseases with improved population coverage. In collaboration with Harvard University and the University of Massachusetts Chan Medical School Diabetes Center of Excellence we will develop a new assay, the Multiplexed Multi-antigen Activation Assay (MMAA), to discover self- antigens that are recognized by cytotoxic T cells in Type 1 Diabetes (T1D) (Aim 1). We will use the self-antigens we have confirmed to design novel multi-epitope tolerization vaccines and test the vaccines for their ability to expand CD4+ TReg cells in PBMCs from T1D donors (Aim 2). We will utilize new machine learning methods to modify and select vaccine epitopes to substantially improve tolerization vaccine population coverage. Our products will be the resulting vaccines.