Process schema for generation of selectively depleted (SD) donor lymphocytes. Starting with recipient peripheral blood mononuclear cells collected by leukapheresis, CD3⁺ lymphocytes were immunomagnetically selected with OKT3 and sheep antimouse (SAM) beads and expanded to generate a stimulator T-cell population of high purity. The unadsorbed donor mononuclear cell (MNC)–rich fraction (responders) from CD34⁺ selection of G-CSF–mobilized PBSCs was cocultured with irradiated, expanded recipient CD3⁺ T lymphocytes (stimulators), and then subjected to 2 cycles of selective depletion with the anti-CD25 immunotoxin (RFT5-SMPT-dgA) before harvest of the final SD cells.