PWM treatment of myeloma cells did not result in increased binding to effectors. Myeloma cell lines COL and MER were used as targets. IL-2–activated PBMC effectors from 2 healthy donors were labeled with the fluorescent lipophilic dye PKH26. The E:T-cell ratio was 1:1. Effectors and targets were allowed to bind for 5 to 10 minutes at 37°C prior to counting.

These data represent the percentage binding ± SEM for 3 individual experiments with each donor. At least 1000 effectors were counted for each E:T combination. The differences were not statistically significant.