Tumor immunization of BMT recipients increases GVT activity against leukemia.

One month after BMT, SW→ B6 recipients (C1498-immune, n = 8) were immunized twice with irradiated C1498 leukemia cells at a 1-week interval. Control recipients (nonimmune, n = 8) were not immunized. 10 days after the 2nd vaccine, 1 × 10⁴ C1498 cells were injected intravenously to simulate relapse after BMT, and C1498-immune recipients were immunized twice more at a 1-week interval. Immunization significantly enhanced survival (P < .0001) compared to nonimmune control recipients.