Agonistic activity of single alanine substitutions of HA-1 on HA-1–specific CTL clones 3HA15 and 5W38 and clone 15.

HA-1⁻ T2 cells were incubated at 37°C with the indicated peptide concentrations. After 30 minutes CTLs were added, and percentage lysis was determined 4 hours later.