INTRATUMORAL INJECTION OF AN ADENOVIRUS EXPRESSING INTERLEUKIN-2 INDUCES REGRESSION AND IMMUNITY IN A MURINE BREAST-CANCER MODEL

Rodent tumor cells engineered to secrete cytokines such as interleukin 2 (IL-2) or IL-4 are rejected by syngeneic recipients due to an enhan ced antitumor host immune response. An adenovirus vector (AdCAIL-2) co ntaining the human IL-2 gene has been constructed and shown to direct secretion of high levels of human IL-2 in infected tumor cells. AdCAIL -2 induces regression of tumors in a transgenic mouse model of mammary adenocarcinoma following intratumoral injection. Elimination of exist ing tumors in this way results in immunity against a second challenge with tumor cells. These findings suggest that adenovirus vectors expre ssing cytokines may form the basis for highly effective immunotherapie s of human cancers.