Background: Conventional therapy for renal cell carcinoma (RCC) using systemic administration of interleukin-2 (IL-2) has shown limited anti-tumor action. The purpose of this study was to investigate the anti-tumor effects of a newly developed immune complex of IL-2 (IC) against RCC.
Methods: IC was prepared by mixing IL-2 and an anti-IL-2 monoclonal antibody at a molar ratio of 2:1. The pharmacokinetics and anti-tumor effects of IC were then studied in a murine RCC line, Renca.
Results: Serum IL-2 levels were sustained longer in mice given IC than in mice given IL-2 alone after either subcutaneous or intratumoral injections. After an intratumoral injection of IC, the IL-2 concentration in the tumor nodules remained higher compared with mice given IL-2 alone. The anti-tumor effect was most pronounced in mice treated with intratumoral injections of IC.
Conclusions: Results obtained here indicate that an immune complex of IL-2 provides a useful tool for the treatment of RCC by altering the pharmacokinetics of IL-2 in vivo.