Gene therapy for gastrointestinal tumors using antigen presenting cells activated with gene transfer

我们研究了是否可以通过在肿瘤上表达CD 40配体（CD 40 L）基因来激活专职抗原呈递细胞（树突状细胞），并随后诱导抗肿瘤免疫。我们逆转录病毒转导肿瘤与CD 40 L基因，并建立CD 40 L表达的肿瘤，其MHC I类表达保持相同的亲本肿瘤。将转导的细胞接种到同基因小鼠中，发现与亲本肿瘤相比，表达CD 40 L的肿瘤的生长显著延迟。一些小鼠完全排斥表达CD 40 L的肿瘤，小鼠产生了抗原特异性保护性免疫。当裸鼠接种表达CD 40 L的肿瘤时，其生长与亲本肿瘤没有差异。在体外培养的CD 40 L表达的肿瘤和骨髓来源的树突状细胞显示，树突状细胞和CD 40 L表达的肿瘤之间的集群形成，而不是母瘤。与表达CD 40 L的肿瘤细胞共培养后，树突状细胞上的MHC II类分子和活化标志物CD 86的表达上调，但与亲代肿瘤细胞共培养后，树突状细胞上的MHC II类分子和活化标志物CD 86的表达上调。活化的树突状细胞分泌IL-12、IL-18、IL-23和Mig。这些数据共同表明，肿瘤上的CD 40 L可以通过CD 40/CD 40 L相互作用激活树突状细胞，并诱导细胞因子和趋化因子的表达，这在T细胞介导的抗肿瘤效应的产生中起着至关重要的作用。

We examined whether professional antigen presenting cells (dendritic cells) could be activated by the expression of CD40 ligand (CD40L) gene on tumors and antitumor immunity was subsequently induced. We retrovirally transduced tumors with the CD40L gene and established CD40L-expressed tumors whose MHC class I expression remained the same as that of parent tumors. Inoculation of the transduced cells into syngeneic mice revealed that growth of CD40L-expressed tumors was significantly retarded compared with that of parent tumors. Some of the mice completely rejected the CD40L-expressed tumors and the mice developed antigen-specific protective immunity. When nude mice were inoculated with the CD40L-expressed tumors, the growth was not different from that of parent tumors. In vitro culture of the CD40L-expressed tumors and bone marrow-derived dendritic cells showed that the cluster formation between dendritic cells and the CD40L-expressed but not parent tumors. The expression of MHC class II and activation marker CD86 on dendritic cells was upregulated after the coculture with CD40L-expressed but not parent tumors. The activated dendritic cells secreted IL-12, IL-18, IL-23 and Mig. These data collectively suggest that CD40L on tumors can activate dendritic cells through CD40/CD40L interaction and induce the expression of cytokines and chemokines, which play a crucial role in the generation of T cell-mediated antitumor effects.