Inhibition of anti-HLA B*3501 allospecific lysis by CTL clone JL12 with peptide analogs of KPIVVLHGY. An HLA B*3501⁺ LCL was tested for lysis by CTL clone JL12 after pretreatment with selected monosubstituted peptide analogs of KPIVVLHGY. The level of lysis of these LCLs without peptide pretreatment was 33.1%. The letter within each graph represents the parent residue being replaced; the horizontal axis lists the residue replacing the parent residue; the vertical axis displays the percent inhibition of lysis relative to the level of lysis of the LCL without exogenous peptide addition. Where peptide increased lysis of the B*3501⁺ LCL, a value of 0% inhibition is shown. Three different peptide concentrations were used (200 μmol/L [▪], 2 μmol/L [], and 0.02 μmol/L [□]) and the E:T ratio was 2:1.