An effective tumor vaccine against malignant melanoma: irradiated autologous tumor cells admixed with MVE-2.

The aim of this study was to develop as effective as possible autologous tumor vaccine which would be at the same time easy to produce, highly controllable, and without undesired side effects on normal tissue. Therefore, irradiated autologous - syngeneic B-16 tumor cells admixed with a non-specific immunomodulator MVE-2 (a polymer fraction of 1,2-co-polymer of divinyl ether and maleic anhydride) were used for subcutaneous (s.c.). or intraperitoneal (i.p.) prevaccination of experimental mice. Compared to the control mice, a statistically significant delay in tumor development of s.c. tumors was achieved in prevaccinated mice (p<0.05). An even better effect was observed in mice challenged i.p. with viable tumor cells. Using a single prevaccination complete protection was obtained in between 40-85% of the experimental mice. When the survivors from the groups injected once with the tumor vaccine were rechallenged with viable tumor cells (101 day after the first tumor challenge, no additional prevaccination), 15.7% remained free of tumor, while the survivors from the groups injected with the tumor vaccine twice and 101 day later rechallenged with viable tumor cells remained free of tumor in 60% of the cases. Based on these results we can postulate that our vaccine is effective for prevention of tumor development. The achieved protection can be augmented with serial vaccinations and can be maintained for a longer period of time.