SYSTEMIC IL-1 AND ADJUVANT TREATMENT OF AN EXPERIMENTAL TUMOR .1. IMMUNE STATUS FOLLOWING TUMOR RECHALLENGE

Local adjuvant therapy of weakly immunogenic tumors protects against primary tumor challenge. However, this form of therapy does not produce long-lasting immunity to the tumor. In this study, local adjuvant therapy combined with systemic IL-1 administration produced not only primary tumor protection, but also long lasting immunity to the tumor. IL-1 and adjuvant protected animals resisted rechallenge with tumor as much as 180 days after initial tumor administration. Resistance to tumor rechallenge was IL-1 dose dependent. IL-1 and adjuvant protected animals also exhibited delayed type hypersensitivity reactions which were tumor-specific. Splenic and lymph node cell populations from IL-1 and adjuvant protected animals mounted tumor-specific lymphoproliferative responses. No such responses were observed in animals which had been administered either IL-1 or adjuvant alone. These results demonstrate that systemic IL-1 functions to augment specific immune protection when administered in conjunction with local adjuvant, resulting in long-lasting tumor immunity.