To examine the long-term immunologic memory, mice were immunized on day 0 and 14 with 105 irradiated B78-D14 cells (100 Gy) together with 10 μg Surek. Other groups were additionally treated with 100 μg HB304 on days 4, 8, 13 and 20. On day 21, all mice received a challenge of 3 × 103 viable B16F0 melanoma cells.