CTL recognition of alanine analogs of the peptide epitope DYSNTHSTRYV. HLA-DR7⁺ LCLs were presensitized with the individual peptides (0.1 μg/mL) and then exposed to DYSNTHSTRYV-specific CTL clones from either donor 1 (HLA-DR7⁺, DR4^-; CTL.56) or donor 2 (HLA-DR7⁺, DR4⁺; CTL.04). An effector-to-target ratio of 5:1 was used in the assay. These data are representative of 3 different experiments based on 8 different CTL clones.