Antitumor effect of human pancreatic cancer cells transduced with cytokine genes which activate Th1 helper T cells.

We have examined antitumor effect of human pancreatic carcinoma cells (AsPC-1) retrovirally transduced with interleukin-12 (IL-12), IL-15 or IL-18 gene in nude mice. The tumor growth of IL-12-expressing AsPC-1 cells was significantly retarded and that of IL-15-expressing cells was also impeded compared with that of wild-type cells, although their in vitro cell growth remained unchanged. However, the expression of IL-18 in AsPC-1 cells did not generate any antitumor effect since the tumor growth of the transduced cells was the same as that of wild-type cells. Thus, the differential actions of these cytokines on non-T cells can generate a variety of antitumor effect in nude mice, although their actions on T cells lineage favor the stimulation of Th1-type helper T cells.