Blocking inhibitory receptors on allogeneic ALAK cells during ex vivo purging of C1498 increases the proportion of mice with long-term survival. B10.D2 ALAK cells were preincubated with normal mouse IgG, 5E6, or 4D11 F(ab′)2 fragments for 2 hours and further incubated with BMCs and C1498 leukemia cells at ALAK-to-tumor (E/T) ratios of 10:1 (A) or 25:1 (B) for 20 to 24 hours, as described in “Materials and methods.” B6 recipients (8-10 mice per group per experiment) were irradiated (8 Gy) and underwent transplantation with cocultured cells at 3 × 104 C1498 per mouse (intravenously) based on the cell numbers at the initiation of the cocultures. Pooled data from 2 independent experiments are shown, and the statistical difference between the groups was determined by log-rank test.
