TCRabX · Structural basis for the therapeutic efficiency of optimal-affinity T cell receptors

Demographic change includes population ageing, and incidence rates begin to increase for many types of cancer in middle-aged and elderly people. Traditional cancer treatment includes surgery, chemotherapy, and radiation therapy, while tumour immunotherapy by T cell receptor (TCR) gene transfer represents an alternative form of treatment. The transfer of tumour-specific TCR genes into patient’s peripheral blood lymphocytes targets cancer specifically and effectively. But while patient-derived low-affinity TCRs do not show therapeutic activity, optimal-affinity TCRs, as isolated from newly-generated antigen-negative humanized mice with a diverse human TCR repertoire, can effectively delay tumour regression. X-ray crystallography is a powerful tool of structural biology, which helps researchers to identify the three-dimensional (3D) structures of biological macromolecules such as TCRs complexed to their cognate peptide-loaded major histocompatibility complex (pMHC) molecules. Recent research uncovered the docking topologies of naturally selected TCRs, but therapeutically efficient optimal-affinity TCRs recognizing tumour-associated self-antigens, have not been analysed to date. The exceptional specificity of TCRs is determined by three complementarity-determining regions (CDRs) of the TCR alpha- and beta-chains. Biomedical research on TCR gene therapy and design of future clinical trials will hugely benefit from the identification of CDR-mediated contact points made between therapeutic TCRs and the pMHC on their target cells. TCRabX is an interdisciplinary research project investigating the 3D structures of 13 TCRs complexed to MHC-I or MHC-II, respectively. It connects innovative clinical immunology research in Berlin/Germany and world-class structural biology research in Melbourne/Australia. The proposed research will enhance the health and well-being of citizens in Europe and worldwide by supporting the advancement of cancer immunotherapy approaches.