Schneider H, Groves M, Mühle C, Reynolds P N, Knight A, Themis M, Carvajal J, Scaravilli F, Curiel D T, Fairweather N F, Coutelle C
Division of Biomedical Sciences, Imperial College School of Medicine, London, UK.
Gene Ther. 2000 Sep;7(18):1584-92. doi: 10.1038/sj.gt.3301270.
The Hc fragment of tetanus toxin (Hc) retains the specific nerve cell binding and transport properties of the holotoxin, but lacks any toxicity. We are investigating the potential for utilising its neurotropism for targeted gene delivery to the central nervous system. Previously we reported the use of Hc-polylysine conjugates for selective gene transfer into neuronal cells in vitro. However, as attempts to apply these constructs in vivo were not successful, we have extended these studies to modification of the tropism of adenoviral vectors. Either Hc-polylysine conjugates or the Fab fragment of a neutralising anti-knob antibody covalently bound to Hc were attached to the virus. Infection of neuronal and non-neuronal cell lines with retargeted virus showed highly increased neuronal cell selectivity, but no significant enhancement of gene delivery into these cells. High concentrations of free Hc blocked the infectivity of the retargeted vector efficiently. Intramuscular injection of retargeted virus into mouse tongues resulted in selective gene transfer to the neurons of the hypoglossal nucleus, where no pathological changes were observed. As differentiated neurons do not undergo cell division, appropriate vectors carrying a thymidine kinase gene, which allows selective elimination of dividing cells, may be exploitable for the treatment of tumours of the central nervous system. The demonstrated suitability of the Hc fragment of tetanus toxin as targeting moiety for viral vectors also indicates a potential for gene therapy of inherited neurodegenerative diseases such as spinal muscular atrophy.
破伤风毒素的Hc片段（Hc）保留了全毒素的特异性神经细胞结合和转运特性，但不具有任何毒性。我们正在研究利用其嗜神经性将基因靶向递送至中枢神经系统的潜力。此前我们报道了使用Hc-聚赖氨酸偶联物在体外将基因选择性转移至神经元细胞。然而，由于将这些构建体应用于体内的尝试未获成功，我们已将这些研究扩展至腺病毒载体嗜性的修饰。将Hc-聚赖氨酸偶联物或与Hc共价结合的中和性抗纤突抗体的Fab片段连接至病毒。用重靶向病毒感染神经元和非神经元细胞系显示神经元细胞选择性显著增加，但基因递送至这些细胞的效率并无显著提高。高浓度的游离Hc可有效阻断重靶向载体的感染性。将重靶向病毒肌肉注射至小鼠舌部可导致基因选择性转移至舌下神经核的神经元，未观察到病理变化。由于分化的神经元不会进行细胞分裂，携带胸苷激酶基因（可选择性消除分裂细胞）的合适载体可能可用于治疗中枢神经系统肿瘤。已证明破伤风毒素的Hc片段作为病毒载体的靶向部分具有适用性，这也表明其在遗传性神经退行性疾病如脊髓性肌萎缩症的基因治疗方面具有潜力。
