Allodepletion specifically abrogates the generation of alloreactive CTLs. Cytotoxicity assay showing lysis of LCL targets by cocultures of donor A PBMCs with recipient B LCLs in the presence or absence of anti-CD25 immunotoxin after secondary stimulation with B LCLs (A-B) or with third-party LCLs (C-D). In each case cytotoxicity was also assayed in the presence of a 20-fold excess of cold HSB-2 targets to assess specificity. Results are the mean specific cytotoxicity ± SD of triplicate wells in an assay representative of 3 experiments with different patient-donor pairs.