Immunotargeting approach utilizing production of oxygen free radicals.

Tumor-specific inhibition of cell proliferation through production of oxygen free radicals was studied by using immunoconjugates. Diethyldithiocarbamate (DDC), an inhibitor of superoxide dismutase activity (SOD), was conjugated with anti-Meth A tumor cell antibodies. The addition of these conjugates in combination with ascorbic acid (AsA) induced marked inhibition of Meth A tumor cell proliferation. Pretreatment of the target cells with these conjugates followed by the addition of AsA was also effective in inhibiting cell proliferation. However, the pretreatment of the target cells with unconjugated anti-Meth A tumor cell antibodies in combination with AsA eliminated the DDC conjugate-mediated antiproliferative effect. These results suggest that the combined use of DDC-anti Meth A tumor cell antibody conjugates with AsA may be a beneficial approach to cancer therapy.