Gauging antigen recognition by human primary T-cells featuring orthotopically exchanged TCRs of choice.

Understanding human T-cell antigen recognition in health and disease is becoming increasingly instrumental for monitoring T-cell responses to pathogen challenge and for the rational design of T-cell-based therapies targeting cancer, autoimmunity and organ transplant rejection. Here we showcase a quantitative imaging platform which is based on the use of planar glass-supported lipid bilayers (SLBs). The latter are functionalized with antigen (peptide-loaded HLA) as adhesion and costimulatory molecules (ICAM-1, B7-1) to serve as surrogate antigen presenting cell for antigen recognition by T-cells, which are equipped with T-cell antigen receptors (TCRs) sequenced from antigen-specific patient T-cells. We outline in detail, how the experimental use of SLBs supports recoding and analysis of synaptic antigen engagement and calcium signaling at the single cell level in response to user-defined antigen densities for quantitative comparison.