Novel gene therapy by modulation of dendritic cells in vivo

1、用F1t3配体和IL-18在体内联合动员和刺激肿瘤浸润性树突状细胞和自然杀伤细胞诱导系统抗肿瘤免疫。用体内电穿孔技术将携带F1t3L基因的表达载体导入荷瘤小鼠体内。联合治疗组：瘤内注射携带IL-18基因的腺病毒载体(Ad.IL-18)。与对照组相比，单独用Ad.IL-18治疗的小鼠有显著的抗肿瘤作用。在未注射的远处肿瘤中，仅在联合治疗的小鼠中观察到显著的抗肿瘤反应。与其他组相比，联合治疗组小鼠淋巴结中的淋巴样细胞对接种的肿瘤细胞和YAC-1细胞具有明显的杀伤活性。联合治疗的肿瘤浸润性DC具有更高的CD86表达和更强的同种异体T细胞刺激能力。提示局部表达IL-18联合F1t3L体内动员DC可作为DC免疫治疗的一种新策略。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CCL 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CCL 21的实验方法。这项体外分析包括从应该表达CCR7的脾细胞中提纯的成熟DC和幼稚T细胞，以及在有或没有重组CCL21蛋白的情况下照射的肿瘤细胞。CCL21诱导初始T细胞产生干扰素，这种作用需要DC与T细胞的直接细胞接触，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.