Results of ELISPOT assays using serial dilutions of the 4 peptides derived from pp65.

The 2 peptides, no. 81 (●) and 83 (▪), that were recognized at picomolar levels share the amino acid sequence QYDPVAALF, with an additional C-terminal phenylalanine for no. 83. The amino acid sequences of peptides no. 80 (♦) and 82 (▴) are VYALPLKML and QYVKVYLESF, respectively. A total of 1000 polyclonal CMV-specific CD8⁺ T cells established from PBMCs of a CMV-seropositive and HLA-A24⁺ donor were cocultured with 50 000 T2-A24 cells in each well in the presence of each peptide at the indicated concentrations.