Householder et al. used RFdiffusion and ProteinMPNN to de novo design an α-helical TCR mimic (TCRm) specific for an NY-ESO-1 peptide on HLA:A*02. This TCRm showed high specificity and affinity, with TCR-like docking that was strongly focused on the upward-facing peptide side chains. While a structure-informed in silico screen of 14,363 HLA-A*02 peptides (detected by immunopeptidomics) predicted two off-target peptides, when incorporated into a T cell engager, the TCRm showed peptide selectivity (in the 1–10 nM range) and supported T cell activation and cytotoxicity. The TCRm also supported antigen-specific T cell responses when incorporated into a CAR.
Contributed by Lauren Hitchings
ABSTRACT: T cell receptor (TCR) mimics offer a promising platform for tumor-specific targeting of peptide-major histocompatibility complex (pMHC) in cancer immunotherapy. In this study, we designed a de novo α-helical TCR mimic (TCRm) specific for the NY-ESO-1 peptide presented by human leukocyte antigen (HLA)-A*02, achieving high on-target specificity with nanomolar affinity (dissociation constant Kd = 9.5 nM). The structure of the TCRm-pMHC complex at 2.05-Å resolution revealed a rigid TCR-like docking mode with an unusual degree of focus on the up-facing NY-ESO-1 side chains, suggesting the potential for reduced off-target reactivity. Indeed, a structure-informed in silico screen of 14,363 HLA-A*02 peptides correctly predicted two off-target peptides, yet our TCRm maintained peptide selectivity and cytotoxicity as a T cell engager. These results represent a path for precision targeting of tumor antigens with peptide-focused α-helical TCR mimics.
Author Info: (1) Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA. Program in Immunology, Stanford University School of Medicine, Stanf
Author Info: (1) Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA. Program in Immunology, Stanford University School of Medicine, Stanford, CA, USA. (2) Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA. (3) Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA. (4) Department of Computer Science, Stanford University, Stanford, CA, USA. (5) Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA. (6) Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA. (7) Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA. (8) Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA. (9) Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA. Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA. (10) Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA. Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA. Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.
