NKG2A/CD94 and TCRs have different recognition and signaling requirements for the HLA-E/peptide complex. (A) Principal component analysis (PCA) on the percentage HLA-E TM staining of the VMAPRTLIL (VM) and VLAPRTLLL (VL) variants on TCR 6 and NKG2A/CD94 expressing cells. Dots are colored based on specificity for either NKG2A/CD94 or TCR 6, shown in the legend. (B) Similar as A, but then between TCR KK50.4 and NKG2A/CD94 expressing cells for the VMAPRTLIL variants. (C) PCA on the reporter signals of TCR KK50.4 and NKG2A/CD94 expressing cells for the VMAPRTLIL variants. (D) Similar as A, but then between TCR KK50.4 and TCR 6 expressing cells for the VMAPRTLIL variants. The top 10% peptides selective for each receptor are named using the single letter amino acid abbreviation, except for (D) as one peptide was recognized by TCR KK50.4. To differentiate between substitutions in the VMAPRTLIL or VLAPRTLLL peptides, the peptide abbreviations in (A). include VM or VL. Substitutions in (B–D) are only in VMAPRTLIL and codes thus refer to peptide position and substitution.