Interleukin 12 potentiates the curative effect of a vaccine based on interleukin 2-transduced tumor cells

The purpose of these studies was to determine whether systemic administration of recombinant interleukin 12 (rIL-12) is able to potentiate an initial, but insufficient T-cell antitumor response. Mice challenged with carcinoma cells engineered to release interleukin 2 (IL-2) and displaying such a response received single or multiple i.p. injections of rIL-12. This combination of systemic rIL-12 and local IL-2 increased the percentage of mice that rejected two different IL-2 gene-transduced tumors. In another set of experiments more closely resembling a clinical situation, IL-2 gene-transduced tumors were used as vaccines in an attempt to cure mice bearing wild-type parental tumors. The combination of these vaccines with systemic rIL-12 cured mice more effectively than rIL-12 and IL-2 gene-transduced tumor vaccines alone.