Wu Zhijian, Asokan Aravind, Samulski R Jude
Gene Therapy Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Mol Ther. 2006 Sep;14(3):316-27. doi: 10.1016/j.ymthe.2006.05.009. Epub 2006 Jul 7.
Recombinant adeno-associated viral (AAV) vectors have rapidly advanced to the forefront of gene therapy in the past decade. The exponential progress of AAV-based vectors has been made possible by the isolation of several naturally occurring AAV serotypes and over 100 AAV variants from different animal species. These isolates are ideally suited to development into human gene therapy vectors due to their diverse tissue tropisms and potential to evade preexisting neutralizing antibodies against the common human AAV serotype 2. Despite their prolific application in several animal models of disease, the mechanisms underlying selective tropisms of AAV serotypes remain largely unknown. Efforts to understand cell surface receptor usage and intracellular trafficking pathways exploited by AAV continue to provide significant insight into the biology of AAV vectors. Such unique traits are thought to arise from differences in surface topology of the capsids of AAV serotypes and variants. In addition to the aforementioned naturally evolved AAV isolates, several strategies to engineer hybrid AAV serotype vectors have been formulated in recent years. The generation of mosaic or chimeric vectors through the transcapsidation or marker-rescue/domain-swapping approach, respectively, is notable in this regard. More recently, combinatorial strategies for engineering AAV vectors using error-prone PCR, DNA shuffling, and other molecular cloning techniques have been established. The latter library-based approaches can serve as powerful tools in the generation of low-immunogenic and cell/tissue type-specific AAV vectors for gene delivery. This review is focused on recent developments in the isolation of novel AAV serotypes and isolates, their production and purification, diverse tissue tropisms, mechanisms of cellular entry/trafficking, and capsid structure. Strategies for engineering hybrid AAV vectors derived from AAV serotypes and potential implications of the rapidly expanding AAV vector toolkit are discussed.
在过去十年中，重组腺相关病毒（AAV）载体已迅速跃居基因治疗的前沿。通过从不同动物物种中分离出几种天然存在的AAV血清型和100多种AAV变体，基于AAV的载体取得了指数级进展。由于这些分离株具有多样的组织嗜性以及逃避针对常见人类AAV血清型2的预先存在的中和抗体的潜力，它们非常适合开发成为人类基因治疗载体。尽管它们在多种疾病动物模型中得到了广泛应用，但AAV血清型选择性嗜性的潜在机制在很大程度上仍不清楚。了解AAV利用的细胞表面受体使用情况和细胞内运输途径的努力，继续为深入了解AAV载体的生物学特性提供重要见解。这种独特的特性被认为源于AAV血清型和变体衣壳表面拓扑结构的差异。除了上述自然进化的AAV分离株外，近年来还制定了几种构建杂交AAV血清型载体的策略。在这方面，通过转衣壳或标记拯救/结构域交换方法分别产生镶嵌或嵌合载体尤为显著。最近，已经建立了使用易错PCR、DNA改组和其他分子克隆技术构建AAV载体的组合策略。后者基于文库的方法可作为生成用于基因递送的低免疫原性和细胞/组织类型特异性AAV载体的强大工具。本综述重点关注新型AAV血清型和分离株的分离、生产和纯化、多样的组织嗜性、细胞进入/运输机制以及衣壳结构的最新进展。讨论了源自AAV血清型的杂交AAV载体的构建策略以及迅速扩展的AAV载体工具包的潜在影响。
