[Fusion vaccine therapy by IL-2-gene-transduced dendritic cells and tumor cells]

We evaluated the usefulness of fusion vaccine prepared from IL-2-gene-transduced splenic dendritic cells (DCs) and fibrosarcoma tumor cells (QRsP) in treating of lung metastasis. The IL-2 or LacZ gene was transferred into spleen-derived DCs using an adenoviral vector. Irradiated QRsP tumor cells were fused with IL-2 gene transduced DCs (fusion/IL-2) or LacZ gene transduced DCs (fusion/LacZ) by polyethyleneglycol. These fusion cells expressed major histocompatibility complex (MHC) class I and MHC class II, CD86, CD11c and CD8alpha. IFN-gamma and cytotoxic T lymphocyte (CTL) activity of splenic lymphocytes in mice vaccinated with fusion cells increased significantly as compared with those of DC or tumor cells vaccinated mice. CTL levels in fusion/IL-2-vaccinated mice were higher than that in fusion/LacZ-vaccinated mice. The number of lung metastasis in the fusion/IL-2 or fusion/LacZ-vaccineatd mice was significantly lower than that in mice vaccinated with DCs, tumor or PBS. The introduction of the IL-2 gene into fusion cells produced more potent therapeutic effects. Our results suggest that the fusion cells prepared from IL-2 gene transduced spleen derived DCs and tumor cells have the ability to induce therapeutic effect against lung metastasis.