Comparison of activation and allodepletion following stimulation with HLA-mismatched PBMCs or LCLs. (A) FACS analysis showing percent CD3⁺/CD25⁺ cells after stimulation with HLA-mismatched PBMCs or LCLs in the presence or absence of immunotoxin. Results are the mean ± SD of 5 HLA-mismatched donor-patient pairs. (B) Primary mixed lymphocyte reactions showing proliferation of 2 × 10⁵ donor PBMCs by HLA-mismatched PBMCs (R/S 1:1; ▦) or LCLs (R/S 40:1; ▪) from the same recipient. The results are the mean specific proliferation of triplicate wells for 6 HLA-mismatched donor-recipient pairs.