Figure 5. Effects of single alanine substitutions in the Tp1_214–224 epitope on recognition by specific CD8⁺ T cell clones.

T cell recognition was examined using a 4-hour ¹¹¹Indium release cytotoxicity assay employing target cells incubated with 1 ug/ml of peptide. The maximum level of cytotoxicity obtained with the native Tp1_214–224 peptide is shown for each clone. Killing of unpulsed target cells was <2% for all clones. The degree of reduction in killing obtained with each of the single Ala substituted peptides (A1–A11) compared to that obtained with the native Tp1_214–224 peptide is represented as follows: 0–20% reduction (white); 21–40% reduction (pale grey); 41–60% reduction (medium grey); 61–80% reduction (dark grey); 81–100% reduction (black). The expressed TCR Vβ genes were identified using Vβ subfamily-specific PCR assays. NT = not tested.