Fig. 2: Determination of the specificity of \({{\mathbf{TRACe{R}}}_{{\mathbf{MHC}}\;{\mathbf{I}},\,{\mathbf{A02}}}^{\mathbf{NY-ESO-1}}}\) against different peptides.
From: Targeting peptide antigens using a multiallelic MHC I-binding system
a, Structure of MHC-presented NY-ESO-1 peptide. Residue positions in yellow are solvent exposed and those in blue have side chains buried in the MHC I groove. T7 is partially solvent exposed. b, Alanine scan of the NY-ESO-1 peptide showing that TRACeR binding is sensitive to S1, M4, W5 and T7 substitutions, representing four of five solvent-exposed positions. The binding signal is shown as the MFI ± s.d. (n = 3 technical replicates). c, Binding signal for alanine scan substitutions on flow cytometry. d, MHC I tetramer SSM on the five key peptide residues responding to TRACeR (top) and 1G4 TCR (bottom). The S1V peptide failed to synthesize by the vendor (filled with gray). e, Normalized enrichment ratio showing enriched peptide sequences binding to TRACeR (top) and 1G4 TCR (bottom) from the randomized triplet library (n = 3 technical replicates). f, Clusters of the combined top 50 peptide sequences binding to TRACeR and 1G4 (based on enrichment ratio). Average distance of NY-ESO-1 peptide to each cluster: cluster 1, 33.5; cluster 2, 33.8; cluster 3, 24.9; cluster 4, 32.2; cluster 5,30.7. g, In vitro tumor cell cytotoxicity assays with \({\rm{TRACeR}}_{\rm{MHC}\;{\rm{I}},\,{\rm{A02}}}^{{\rm{NY}}-{\rm{ESO}}-1}\) anti-CD3 BiTEs. The percentage of live tumor cells was normalized to PBS-treated control cells (n = 6 replicates using T cells from two independent donors).
