Directed evolution of human T-cell receptors with picomolar affinities by phage display

Peptides derived from almost all proteins, including disease-associated proteins, can be presented on the cell surface as peptide-human leukocyte antigen (pHLA) complexes. T cells specifically recognize pHLA with their clonally rearranged T-cell receptors (TCRs), whose natural affinities are limited to ∼1-100 μM. Here we describe the display of ten different human TCRs on the surface of bacteriophage, stabilized by a nonnative interchain disulfide bond. We report the directed evolution of high-affinity TCRs specific for two different pHLAs: the human T-cell lymphotropic virus type 1 (HTLV-1) tax11-19 peptide-HLA-A*0201 complex and the NY-ESO-1157-165 tumor-associated peptide antigen-HLA-A*0201 complex, with affinities of up to 2.5 nM and 26 pM, respectively, and we demonstrate their high specificity and sensitivity for targeting of cell-surface pHLAs.