Precise targeting of T1D specific T cells using CAR and peptide-MHC chimeric antigen ligands

Project Summary Type 1 diabetes (T1D) is an incurable autoimmune disease manifested through the immune destruction of islet beta cells. This proposal describes a unique CAR T cell approach to eliminate islet-autoreactive T cells, thus eliminating the source of the autoimmunity and providing a highly specific treatment for T1D. We will leverage our recently developed split CAR system with a chimeric antigen ligand (CAL) adaptor consisting of a pMHC multimer fused to a recruitment molecule. The addition of CAL will bind to the autoreactive TCR and recruit the universal CAR T cells to kill autoreactive T1D specific T cells. The proposed experiments will test the hypoth- eses that (1) our modular CAR/CAL systems are uniquely suited for specifically targeting multiple auto- reactive TCRs, and (2) that we can identify novel epitopes against T1D specific TCRs to be paired with the CAR/CAL system. Importantly, preliminary data support these hypotheses, and well-characterized clinical specimens from T1D patients and rigorous experimental designs are established in this proposal with essential cross-disciplinary collaborations and expertise that encompass synthetic biology, large-scale epitope discovery, T1D immunology, and humanized T1D animal modeling. The specific aims of this five-year proposal are as follows: Aim 1 establish and optimize the CAL system against antigen-specific human TCRs, Aim 2 characterize the autoreactivity of TCRs from T1D patients/donors and identify peptide-MHC against these TCRs, and Aim 3 evaluate the performance of the CAL system in humanized T1D animal models. Outcomes from this work will establish the clinical potential of the CAR/CAL system as a safe, effective, and potentially curative T1D treatment.