MLCs and NK assays from 1 dog (H388) treated with ²¹¹At–anti-CD45 mAb-conditioned nonmyeloablative DLA-identical bone marrow transplantation. In vitro lymphocyte function from 1 representative dog (H388) treated with 539 μCi/kg ²¹¹At-labeled anti-CD45 mAb on day −3 followed by a marrow graft from a DLA-identical donor on day 0. The total anti-CD45 dose was 0.5 mg/kg, whereof 10% was administered as unlabeled mAb 1 hour before the radioimmunoconjugate. Data were obtained before radiolabeled antibody infusion, day −1 before transplantation, and 33 days after transplantation. MLC data are expressed as mean counts per minute from triplicate wells of recipient response to autologous cells, donor cells, cells from an unrelated dog, and to concanavalin A as internal assay control. Error bars represent SEM from 3 wells. In the NK assay, cytotoxicity is expressed as a percentage of specific lysis of target cells (canine thyroid adenocarcinoma cells), calculated using the mean value of triplicate cultures. Effector-to-target ratios were 50:1, 25:1, 12.5:1, and 6.25:1, respectively.