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 μM1. Here we describe the display of ten different human TCRs on the surface of bacteriophage, stabilized by a nonnative interchain disulfide bond2. 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 complex3 and the NY-ESO-1157–165 tumor-associated peptide antigen–HLA-A*0201 complex4, 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.