The positive clinical outcomes in adeno-associated virus (AAV)-mediated retinal gene therapy have often been attributed to the low immunogenicity of AAVs along with the immune-privilege of the eye. However, several recent preclinical studies and clinical trials have shown potential for inflammatory responses to AAV mediated gene therapy. Our current understanding of the factors contributing to intraocular inflammation such as the existence of serum antibodies against AAVs prior to injection and their contribution to increases in antibody levels post-injection is incomplete. The parameters that regulate the generation of new antibodies in response to the AAV capsid or transgene post-injection after intraocular administration are also insufficiently described. In this study we carried out a retrospective analysis of the pre-existing serum antibodies in correlation with changes in antibody levels after intraocular injections of AAV in non-human primates (NHPs). We analyzed NHP serums for the presence of both Binding Antibodies (BABs), as well as a subset of these called Neutralizing Antibodies (NABs) that impede AAV transduction upon binding. We observed significantly higher pre-existing serum BABs against AAV8 compared to other serotypes. We observed a dose-dependent increase in both BABs and NABs in the serums collected post-injection, irrespective of the serotype or the mode of injection. Lastly, we were able to demonstrate a co-relation between the serum BAB levels with clinical grading of inflammation and levels of transgene expression.

中文翻译：

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非人灵长类动物对眼内 AAV 载体给药的全身和局部免疫反应

腺相关病毒 (AAV) 介导的视网膜基因治疗的积极临床结果通常归因于 AAV 的低免疫原性以及眼睛的免疫特权。然而，最近的几项临床前研究和临床试验表明，AAV 介导的基因治疗可能引起炎症反应。我们目前对导致眼内炎症的因素的理解是不完整的，例如注射前存在针对 AAV 的血清抗体及其对注射后抗体水平增加的贡献。在眼内给药后，调节新抗体产生以响应 AAV 衣壳或转基因后的参数也没有得到充分描述。在这项研究中，我们对与非人类灵长类动物 (NHP) 眼内注射 AAV 后抗体水平变化相关的预先存在的血清抗体进行了回顾性分析。我们分析了 NHP 血清中是否存在两种结合抗体 (BAB)，以及其中一部分被称为中和抗体 (NAB) 的抗体，这些抗体在结合时会阻碍 AAV 转导。我们观察到与其他血清型相比，针对 AAV8 的预先存在的血清 BAB 明显更高。我们观察到注射后收集的血清中 BAB 和 NAB 的剂量依赖性增加，无论血清型或注射方式如何。最后，我们能够证明血清 BAB 水平与炎症的临床分级和转基因表达水平之间的相互关系。