(A) Phenotype of the clones. The A2 Gag and the A2 Pol clones were analyzed by flow cytometry. The y-axes indicate staining with CD8-PE and the x-axes represent staining with control antibody, CD3-FITC, CD28-FITC, and Fas-FITC. (B) Specificity of the A2 Gag clone. The panel shows the A2 Gag clone stained with anti–CD8-tricolor and either an irrelevant A2 tetramer- (complexed with an EBV peptide) or A2 Gag tetramer-PE. (C) The sequences of the CDR3 regions of the A2 pol clone T-cell receptor. The V and Vβ usage and CDR3 sequences of the TCR of the pol-specific CTL clone were the same in 18 transcripts, providing evidence of clonality.