Modulation of specific active immunization against murine melanoma using recombinant cytokines

Specific active immunization with tumour cells and IL-1 beta or IL-2 was examined in a murine model. Mice were treated with irradiated B16 melanoma, IL-1 beta or IL-2 only, or with B16 plus cytokines prior to i.v. challenge with viable B16. Lung metastases were recorded after 28 days. Treatment with cytokine alone was not protective. Treatment with B16 alone afforded moderate protection. Treatment with B16 in combination with either cytokine resulted in a significant level of B16 specific protection which was dependent on the dose of cytokine used. Multiple immunizations with B16 provided limited protection which was significantly improved with IL-2. Immunization with B16 in combination with both cytokines at doses that alone failed to enhance immunity resulted in significant protection, suggesting that the two cytokines act at least additively. These studies demonstrate the significant benefit of specific active immunization with tumour cells in combination with low doses of IL-1 beta or IL2.