Novel gene therapy by modulation of dendritic cells in vivo

1、F1 t3配体和IL-18联合动员和刺激肿瘤浸润性树突状细胞和自然杀伤细胞体内诱导系统性抗肿瘤免疫我们重点研究了F1 t3配体（F1 t3 L）联合IL-18对肿瘤微环境中树突状细胞的调节作用。用体内电穿孔（WE）携带F1 t3 L cDNA的表达质粒处理肿瘤接种小鼠。另一组小鼠瘤内注射携带IL-18基因的腺病毒载体（Ad.IL-18）作为联合治疗。与对照组相比，单独用Ad.IL-18治疗的小鼠中观察到显著的抗肿瘤效果。在未注射的远端肿瘤中，仅在用组合疗法治疗的小鼠中观察到显著的抗肿瘤应答。与其他组相比，联合治疗组淋巴结中的类淋巴结细胞对接种的肿瘤细胞和YAC-1细胞显示出显著的细胞溶解活性。联合治疗的肿瘤浸润DC显示出更高的CD 86表达和更有效的同种异体T细胞刺激能力。这些结果可能表明，局部表达IL-18结合体内DC动员与F1 t3 L是一种新的策略，DC免疫治疗的临床应用。2、CC-趋化因子配体21在T细胞介导的抗肿瘤免疫中的作用为了研究CC-趋化因子配体21在T细胞介导的抗肿瘤免疫中的作用机制，我们建立了一种体外分析CC-趋化因子配体21的实验方法。该体外分析由成熟DC和从应表达CCR 7的脾细胞纯化的初始T细胞以及在存在或不存在重组CCL 21蛋白的情况下辐照的肿瘤细胞组成。CCL 21诱导初始T细胞产生IFN-□，这种作用需要DC与T细胞直接接触，并促进肿瘤特异性CTL的产生。

1, Combined mobilization and stimulation of tumor-infiltrating dendritic cells and natural killer cells with F1t3 ligand and IL-18 in vivo induces systemic anti-tumor immunityWe focused on the modulation of DCs in tumor microenvironment using F1t3 ligand (F1t3L) combined with IL-18. Tumor-inoculated mice were treated with in vivo electroporation (WE) of expression plasmids carrying cDNA of F1t3L. As combination therapy, mice in the other group were treated with intra-tumoral injection of adenoviral vector carrying IL-18 gene (Ad.IL-18). Significant anti-tumor effect was observed in mice treated with Ad.IL-18 alone when compared with that of control. In un-injected distant tumor, significant anti-tumor responses were observed only in the mice treated with combination therapy. Lymphoid cells in lymph nodes with combination therapy showed significant cytolytic activity against inoculated tumor cells and YAC-1 cells when compared with the ones in other groups. Tumor-infiltrating DCs with combination therapy showed higher CD86 expression and more potent allogeneic T cell stimulatory capacity. These results may suggest that local expression of IL-18 combined with in vivo DC mobilization with F1t3L is clinically applicable as a new strategy of DC immunotherapy. (Submitted for publication)2, The roles of CC-chemokine ligand 21 on T cell mediated anti-tumor immunityIn order to examine the underlying mechanism of CCL 21 on T cell mediated anti-tumor immunity, we developed an experimental approach of in vitro analysis of CCL 21. This in vitro analysis consisted of mature DCs and naive T cells purified from splenocytes which should express CCR7, and irradiated tumor cells in the presence or absence of recombinant CCL21 protein. CCL21 induced IFN-□ production from naive T cells and this effect needed the direct cell contact between DCs and T cells, and promoted the generation of tumor-specific CTLs.