BOB1-reactive T-cell clones exhibit varying degrees of peptide sensitivity and avidity. BOB1-reactive T-cell clones recognizing peptide BOB1₂₄₅ presented in HLA-A2 were assessed for peptide sensitivity by peptide titration and their capacity to recognize endogenously processed peptide. (A) Shown are histograms of 3 representative T-cell clones stained with pMHC tetramer BOB1₂₄₅:A2 (red line) or control pMHC tetramer composed of irrelevant USP11-derived peptide FTWEGLYNV bound to HLA-A2 (USP11_FTW:A2; blue area). T-cell clone HSS12 specific for USP11_FTW:A2 served as control. (B-C) BOB1-reactive T-cell clones were coincubated with K562-A2 cells pulsed with (B) titrated BOB1₂₄₅ peptide or (C) 3 BOB1-expressing HLA-A2⁺ B-LCLs. BOB1⁻ K562-A2 cells were used as control. Shown are means with standard deviations of 1 representative experiment carried out in duplicate.