内皮祖细胞(EPC)可归巢肿瘤参与肿瘤血管生成。双特异抗体(BsAb)可将两种效应细胞特异结合。采用超顺磁性氧化铁纳米粒子(SPIO)标记有可能活体示踪移植的EPC。本研究拟构建CD34×AFP双特异抗体anti-CD34×anti-AFP，将SPIO与该BsAb连接，制备成SPIO-anti-CD34×anti-AFP复合物(SPIO-BsAb)。构建内皮抑素和自杀基因的融合基因重组腺病毒pAd-CMV-ES/CD，体外转染EPC，然后以SPIO-BsAb标记EPC，将该EPC移植入肝癌大鼠体内，利用anti-AFP的免疫导向作用及EPC的肿瘤归巢性双重介导使EPC高效迁移到肝癌组织，发挥融合基因抑制肿瘤血管生成及直接杀伤肿瘤细胞的双重作用；同时采用磁共振(MR)成像活体监测EPC向肝癌组织的归巢过程。这将有可能为肝癌及其它恶性肿瘤的免疫导向EPC抗肿瘤基因治疗提供新思路和新途径。

Endothelial progenitor cell (EPC) have the ability of targeted migrate and incorporate into sites of tumor neovascularization and participate in the development of tumor vascularization. Bispecific antibody (BsAb) might bind specifically the two types of cells. Superparamagnetic iron oxide nanoparticles (SPIO) were marked with In Vivo Tracking transplant EPC. This study intends to build of CD34 × AFP bispecific antibody which is anti-CD34 × anti-AFP and prepare complexes of SPIO-anti-CD34 × anti-AFP by connecting the SPIO with the BsAb. In the study, we plan to construct recombine-adenovirus by fusion gene combined endostatin gene with suicide gene, pAd-CMV-ES/CD, which were transfected into EPC in vitro. The EPC were labeled by the SPIO-anti-CD34 × anti-AFP whereafter and administrated into the rat hepatocarcinoma models via vascular. The implanted labeled EPC might be efficiently transfered into the hepatocarcinoma tissue duo to the anti-AFP immune oriented role and its capability of targeted migrating and incorporating into tumor neovascularization, and play dual role of fusion gene inhibition of angiogenic and direct anti-tumor cell; simultaneously the hepatocarcinoma tissue-targeted homing process of intravenously implantated EPC was monitored by MR in vivo. It might provide a new idea and method of immune-oriented EPC anti-tumor gene therapy for liver cancer and other malignancies..