Immunostimulatory therapy with anti-CD3 monoclonal antibodies and recombinant interleukin-2: Heightened in vivo expression of mRNA encoding cytotoxic attack molecules and immunoregulatory cytokines and regression of murine renal cell carcinoma

The response rate to IL-2 immunotherapy, currently used in the treatment of metastatic renal cell cancer, is limited. Based on our earlier demonstration that a combined regimen of monoclonal antibodies directed at the T cell surface protein CD3 (anti-CDS mAbs) and IL-2 is synergistic in constraining tumor progression in a murine fibrosarcoma hepatic metastasis model, we have explored the efficacy of an anti-CD3 mAbs plus IL-2 regimen in a murine renal cell cancer model. Our studies demonstrate that a regimen of anti-CDS mAbs plus IL-2 is superior to treatment with anti-CDS mAbs alone or IL-2 alone in reducing the number of pulmonary metastases and in prolonging survival. Moreover, the efficacious regimen is associated with heightened intrapulmonary expression of mRNA encoding cytotoxic attack molecules (perforin, granzyme B) and immunoregulatory cytokines (IL-4, IL-10 and IFN-gamma).