Antagonism of CTL clone JL20 with eight different APLs. An LCL from donor CS (HLA A3, A23, B*3501, B44) was tested for lysis by CTL clone JL12 after pretreatment with a range of concentrations of synthetic peptide APLs. The data are presented as percent lysis and percent inhibition of lysis relative to the level of lysis of the LCL without exogenous peptide addition (32.7%). The E:T ratio was 2:1.