De novo design and structure of a peptide-centric TCR mimic binding module.

Householder, Karsten D; Xiang, Xinyu; Jude, Kevin M; Deng, Arthur; Obenaus, Matthias; Zhao, Yang; Wilson, Steven C; Chen, Xiaojing et al. · Science · 2025

basic_science · Level V

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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 <i>K</i><sub>d</sub> = 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.

Medical subject headings