Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48823, USA.
Blood. 2010 Sep 9;116(10):1669-77. doi: 10.1182/blood-2010-03-276949. Epub 2010 May 28.
Adenovirus (Ad) vectors are widely used in human clinical trials. However, at higher dosages, Ad vector-triggered innate toxicities remain a major obstacle to many applications. Ad interactions with the complement system significantly contribute to innate immune responses in several models of Ad-mediated gene transfer. We constructed a novel class of Ad vectors, genetically engineered to "capsid-display" native and retro-oriented versions of the human complement inhibitor decay-accelerating factor (DAF), as a fusion protein from the C-terminus of the Ad capsid protein IX. In contrast to conventional Ad vectors, DAF-displaying Ads dramatically minimized complement activation in vitro and complement-dependent immune responses in vivo. DAF-displaying Ads did not trigger thrombocytopenia, minimized endothelial cell activation, and had diminished inductions of proinflammatory cytokine and chemokine responses. The retro-oriented display of DAF facilitated the greatest improvements in vivo, with diminished activation of innate immune cells, such as dendritic and natural killer cells. In conclusion, Ad vectors can capsid-display proteins in a manner that not only retains the functionality of the displayed proteins but also potentially can be harnessed to improve the efficacy of this important gene transfer platform for numerous gene transfer applications.
腺病毒（Ad）载体在人类临床试验中被广泛应用。然而，在较高剂量下，Ad 载体引发的固有毒性仍然是许多应用的主要障碍。Ad 与补体系统的相互作用在几种 Ad 介导的基因转移模型中显著促进了固有免疫反应。我们构建了一类新型的 Ad 载体，通过基因工程将天然和反向取向的人补体抑制剂衰变加速因子（DAF）作为一种融合蛋白从 Ad 衣壳蛋白 IX 的 C 末端展示。与传统的 Ad 载体相比，DAF 展示的 Ads 在体外显著最小化了补体激活，并且在体内最小化了补体依赖性免疫反应。DAF 展示的 Ads 不会引发血小板减少症，最小化了内皮细胞激活，并且降低了促炎细胞因子和趋化因子反应的诱导。DAF 的反向展示在体内实现了最大的改善，固有免疫细胞（如树突状细胞和自然杀伤细胞）的激活减少。总之，Ad 载体可以以一种不仅保留所展示蛋白功能的方式展示蛋白，并且还可以潜在地利用这种方式来提高这个重要的基因转移平台在许多基因转移应用中的功效。
