Tseng Yu-Shan, Vliet Kim Van, Rao Lavanya, McKenna Robert, Byrne Barry J, Asokan Aravind, Agbandje-McKenna Mavis
Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, USA.
Department of Genetics and The Gene Therapy Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
J Virol Methods. 2016 Oct;236:105-110. doi: 10.1016/j.jviromet.2016.07.009. Epub 2016 Jul 14.
Adeno-associated viruses (AAVs) are promising viral vectors for therapeutic gene delivery, and the approval of an AAV1 vector for the treatment of lipoprotein lipase deficiency has heralded a new and exciting era for this system. However, preclinical and clinical studies show that neutralization from pre-existing antibodies is detrimental for medical application and this hurdle must be overcome before full clinical realization can be achieved. Thus the binding sites for capsid antibodies must be identified and eliminated through capsid engineering. Towards this goal and to recapitulate patient polyclonal responses, a panel of six new mouse monoclonal antibodies (MAbs) has been generated against AAV8 and AAV9 capsids, two vectors being developed for therapeutic application. Native (capsid) dot blot assays confirmed the specificity of these antibodies for their parental serotypes, with the exception of one MAb, HL2372, selected to cross-react against both capsids. Furthermore, in vitro assays showed that these MAbs are capable of neutralizing virus infection. These MAbs will be utilized for structural mapping of antigenic footprints on their respective capsids to inform development of the next generation of rAAV vectors capable of evading antibody neutralization while retaining parental tropism.
腺相关病毒（AAV）是用于治疗性基因递送的有前景的病毒载体，一种AAV1载体被批准用于治疗脂蛋白脂肪酶缺乏症，这为该系统开创了一个崭新且令人兴奋的时代。然而，临床前和临床研究表明，预先存在的抗体产生的中和作用对医学应用不利，在实现全面临床应用之前必须克服这一障碍。因此，必须通过衣壳工程来识别并消除衣壳抗体的结合位点。为实现这一目标并模拟患者的多克隆反应，已针对AAV8和AAV9衣壳产生了一组六种新的小鼠单克隆抗体（MAb），这两种载体正被开发用于治疗应用。天然（衣壳）斑点印迹分析证实了这些抗体对其亲本血清型的特异性，但有一种单克隆抗体HL2372除外，它被选择为对两种衣壳都有交叉反应。此外，体外试验表明这些单克隆抗体能够中和病毒感染。这些单克隆抗体将用于在各自衣壳上对抗原足迹进行结构定位，以为下一代能够逃避抗体中和同时保留亲本嗜性的重组腺相关病毒（rAAV）载体的开发提供信息。
