Adoptive immunotherapy with Tregs is a promising approach for preventing or treating type 1 diabetes. Islet antigen–specific Tregs have more potent therapeutic effects than polyclonal cells, but their low frequency is a barrier for clinical application. To generate Tregs that recognize islet antigens, we engineered a chimeric antigen receptor (CAR) derived from a monoclonal antibody with specificity for the insulin B chain 10–23 peptide presented in the context of the IAg7 MHC class II allele present in NOD mice. Peptide specificity of the resulting InsB-g7 CAR was confirmed by tetramer staining and T cell proliferation in response to recombinant or islet-derived peptide. The InsB-g7 CAR redirected NOD Treg specificity such that insulin B 10–23–peptide stimulation enhanced suppressive function, measured via reduction of proliferation and IL-2 production by BDC2.5 T cells and CD80 and CD86 expression on dendritic cells. Cotransfer of InsB-g7 CAR Tregs prevented adoptive transfer diabetes by BDC2.5 T cells in immunodeficient NOD mice. In WT NOD mice, InsB-g7 CAR Tregs prevented spontaneous diabetes. These results show that engineering Treg specificity for islet antigens using a T cell receptor–like CAR is a promising therapeutic approach for the prevention of autoimmune diabetes.
Justin A. Spanier, Vivian Fung, Christine M. Wardell, Mohannad H. Alkhatib, Yixin Chen, Linnea A. Swanson, Alexander J. Dwyer, Matthew E. Weno, Nubia Silva, Jason S. Mitchell, Paul C. Orban, Majid Mojibian, C. Bruce Verchere, Brian T. Fife, Megan K. Levings