Engineered AAV vector minimizes in vivo targeting of transduced hepatocytes by capsid-specific CD8+ T cells
Engineered AAV vector minimizes in vivo targeting of transduced hepatocytes by capsid-specific CD8+ T cells
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DOI：
10.1182/blood-2012-10-460733
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发表时间：
2013-03-21
期刊：
影响因子：
20.3
通讯作者：
Herzog, Roland W.
中科院分区：
文献类型：
--
作者：
Martino, Ashley T.;Basner-Tschakarjan, Etiena;Herzog, Roland W.
最近的临床试验表明，逃避CD 8（+）T细胞对病毒衣壳的反应是成功的肝脏定向基因治疗血友病的腺相关病毒（AAV）载体的关键。缺乏临床前模型来测试使用替代血清型或衣壳变体是否可以避免这种有害的反应。在此，研究了CD 8（+）T细胞（“cap-CD 8”，对人B*0702或鼠H2-L-d分子呈递的衣壳表位具有特异性）靶向AAV感染的肝细胞的能力。在基于过继转移离体扩增的cap-CD 8的鼠模型中，AAV 2转导的肝脏显示出CD 8（+）T细胞浸润、转氨酶升高、因子IX转基因表达的显著降低和转导肝细胞的损失。AAV 8基因转移导致对cap-CD 8的易感性延长，与最近的临床发现一致。相比之下，使用已知较少被蛋白酶体降解的AAV 2（Y-F）突变体衣壳，保留了转基因表达并在很大程度上避免了肝毒性。体外试验证实，与AAV 2相比，该衣壳的主要组织相容性复合物I类呈递减少，并杀死人或鼠肝细胞。总之，AAV衣壳可以被工程化以显著降低被细胞毒性T淋巴细胞破坏的风险，而使用替代血清型本身并不能绕过这一障碍。
Recent clinical trials have shown that evasion of CD8(+) T-cell responses against viral capsid is critical for successful liver-directed gene therapy with adeno-associated viral (AAV) vectors for hemophilia. Preclinical models to test whether use of alternate serotypes or capsid variants could avoid this deleterious response have been lacking. Here, the ability of CD8(+) T cells ("cap-CD8," specific for a capsid epitope presented by human B*0702 or murine H2-L-d molecules) to target AAV-infected hepatocytes was investigated. In a murine model based on adoptive transfer of ex vivo expanded cap-CD8, AAV2-transduced livers showed CD8(+) T-cell infiltrates, transaminitis, significant reduction in factor IX transgene expression, and loss of transduced hepatocytes. AAV8 gene transfer resulted in prolonged susceptibility to cap-CD8, consistent with recent clinical findings. In contrast, using an AAV2(Y-F) mutant capsid, which is known to be less degraded by proteasomes, preserved transgene expression and largely avoided hepatotoxicity. In vitro assays confirmed reduced major histocompatibility complex class I presentation of this capsid and killing of human or murine hepatocytes compared with AAV2. In conclusion, AAV capsids can be engineered to substantially reduce the risk of destruction by cytotoxic T lymphocytes, whereas use of alternative serotypes per se does not circumvent this obstacle.