Effects of the immunosuppressive drug niridazole in isogeneic and allogeneic mouse tumor systems in vivo.

In both isogeneic (Sarcoma 1 in A/JAX mice) and allogeneic (Sarcoma 180 in C57BL/6 mice) mouse tumor systems, treatment of the tumor-bearing mice with niridazole, an antiprarasitic drug, known to be a potent suppressor of cell mediated but not humoral immunity caused enhancement of metastases to regional popliteal nodes. Niridazole also inhibited tumor growth in vivo, as manifested by a significant decrease in the weight of the primary tumors. The enhancement of metastases is attributed to the suppression of cell-mediated immunity by the drug, but the mechanism of tumor-growth inhibition is not yet clear.