Bryce Anderson, Brigham Young University
Microbiology and Molecular Biology
Antigen presenting cells digest and display peptides from foreign and infected cells on the major histocompatibility complex (MHC) that are recognized by T-cells through their T cell receptor (TCR). The affinity of TCR:peptide-MHC interactions has been shown to be low however, and in order to effectively use a soluble TCR for therapeutics we need to engineer TCRs with increased affinity. To do this, we have designed a single chain TCR (ValphaVbeta) called LLO118 that is specific for a naturally occurring Listeria monocytogenes epitope. Using yeast display, stable mutants that expressed the LLO118 scTCR at higher levels than the wild type on the surface of yeast were isolated and sequenced. In order to improve affinity of LLO118 we are mutating amino acid residues in the complementarity determining regions, sites important for the TCR to bind with the peptide-MHC. We are generating unique libraries of yeast cells with TCRs that have potential affinity mutations and using fluorescently labeled peptide-MHC tetramers to select cells that have TCRs with higher affinity. By repeating this process with the cells that have higher affinity we are working to get a TCR that binds with much higher affinity than the wild type TCR. These high affinity TCRs are promising for further research in connecting them to a cytokine, greatly reducing systemic damage and other complications caused by administration of this cytokine throughout the body. Thus, our goal is to design a high affinity TCR fused to a cytokine that can be tested for therapeutic use in targeting specific cells in the immune response and improving T cell memory.