Abstract Text: T cells recognizing self peptides play an important role in the development and regulation of autoimmune diseases. Identifying the specific T cell antigens involved in autoimmunity may yield improved diagnostics, disease classifications, and therapeutic targets. However, discovering T cell antigens for autoimmunity is a significant challenge, partly due to the diversity of potential tissue antigens and limited tools for multiplexed antigen mapping. To address this challenge, we have developed a synthetic biosensor that allows for the detection of immunologic synapse formation at a single cell level. Engineered antigen presenting cells (APCs) that autonomously present genetically encoded peptide antigens to T cells are equipped with a surface receptor that detects the mechanical pulling force between activated LFA-1 and ICAM1 at the immunologic synapse. Biosensor engagement triggers expression of a selectable marker so that APCs presenting relevant peptides can be isolated and sequenced for antigen identification. We have demonstrated efficient multiplexed identification of TCR targets from among hundreds of MHC class I or class II presented peptides. Our technology has potential to facilitate autoimmune T cell antigen discovery to improve immunodiagnostics and pave the way for precision immunotherapies.
