SELECTIVE CYTOTOXICITY OF Y-90 LABELED T101 MONOCLONAL-ANTIBODY ON HUMAN-MALIGNANT T-CELL LINES

Yttrium-90 radiolabeled antibodies are currently being evaluated as ra dioimmunotherapeutic reagents. In this study we evaluated whether Y-90 labeled T101, a murine IgG2a monoclonal antibody (MoAb) that recogniz es CD5 could selectively induce cytotoxic damage to cells in culture. Two CD5 positive cell lines, HUT102 and CCRF-CEM cells and PGT a CD5 n egative cell line was treated with 0.005 to 5 mu Ci of Y-90 T101. Afte r 48 and 72 hrs incubation, cytotoxicity was measured using thymidine incorporation as a marker. In addition to treatment with Y-90 labeled T101, control studies included Y-90 DTPA, Y-90 96.5 (non-specific MoAb ), and excess unlabeled T101 prior to Y-90 T101. Selective cytotoxicit y was observed with the Y-90 T101.