THERAPEUTIC EFFECT OF DENDRITIC CELLS TRANSDUCED WITH TH1-TYPE-CYTOKINE-GENES BY RECOMBINANT ADENOVIRUS VECTOR ON GASTROINTESTINAL TUMOR GROWTH

我们已经证明逆转录病毒转导Th-1型细胞因子基因（白介素2,12,15,18）而不是Th-2型细胞因子基因（IL-4, IL-6）进入结肠。26 .肿瘤细胞具有抗肿瘤作用。本实验成功抑制了同基因小鼠结肠26 /Th-1型细胞因子基因的生长。在该实验系统中，联合s.c注射结肠26/GM-CSF和/IL-4肿瘤细胞也利用树突状细胞（DC）的潜在活性产生抗肿瘤作用。DC刺激抗肿瘤免疫应答是启动抗肿瘤免疫机制的关键。为了在荷瘤小鼠中增强这种作用，利用重组缺陷腺病毒（AxCAhIL-2）在体外感染Ba1b/C小鼠骨髓（BM）来源的DC细胞进行基因工程改造，使其产生IL-2。用小鼠IL-4 （1000 u/ml）和GM-CSF（1000 u/ml）培养骨髓细胞5 ~ 7 d，用MOI 30感染AxCAhIL-2，生成DC细胞。经腺病毒转导的IL-2基因在感染后产生大量的IL-2蛋白。瘤内注射表达IL-2的dc可显著抑制肿瘤生长，延长dc治疗小鼠的生存期（p<0.001）。多次注射DCs/AxCAhIL-2增强了抗肿瘤作用，增加了巨噬细胞向肿瘤外周部位的浸润。这些数据提示DC/腺病毒介导的细胞因子基因治疗的可能性。

We have demonstrated that retrovirally transduced Th-1 type cytokine genes (Interleukin 2, 12, 15, 18 ) not Th-2 type cytokine genes( IL-4, IL-6) into colon.26 tumor cells elicit anti-tumor-effect. Growth of colon 26 /Th-1 type cytokine genes were successfully suppressed in syngeneic mice in our laboratory. In that experimental system, combined s.c. injection of colon 26/GM-CSF and /IL-4 tumor cells also elicit anti-tumor effect using potential activity of dendritic cells (DC)., Stimulation of the anti-tumor immune response by DC is critical to initiate anti-tumor immune machinery. To enhance this effect in tumor-bearing mice, bone marrow (BM) derived DC cells from Ba1b/C mice were genetically engineered to produce IL-2 by ex-vivo infection with a recombinant defective adenovirus (AxCAhIL-2). DC cells were generated from bone marrow cells cultured with mouse IL-4 (1000 u/ml) and GM-CSF(1000 u/ml) for 5 through 7 days and infected with AxCAhIL-2 with MOI 30. Those adenovirally transduced IL-2 gene produced high amount of IL-2 protein from DCs after infection. Intratumoral injection of IL-2 expressing DCs suppressed tumor growth profoundly, and prolonged the survival of the mice treated with those DCs (p<0.001). Multiple injection of DCs/AxCAhIL-2 enhanced the anti-tumor effect and increased the infiltration of macrophage to the peripheral site of tumor. These data suggest the possibility of DC/adenovirus mediated cytokine gene therapy.