Neutralizing antibodies (NAbs) strongly limit adeno-associated virus (AAV) vector transduction and repeated administration. Previous studies have shown that NAbs induced by AAVs are associated with T and B cell activation and that the B7/CD28 and CD40/CD40L costimulation signaling pathways are involved. Cytotoxic T lymphocyte-associated antigen 4 (CTLA4) and CD40 are vital molecules that participate in the costimulatory pathway. In this study, we evaluated CTLA4-Ig and CD40-Ig immunosuppreve efficacies through AAV and investigated their effects on the feasibility for multiple systemic administrations of AAV vectors. The results showed that a single administration of AAV vector carrying either CTLA4-Ig alone or with CD40-Ig could greatly reduce the level of NAbs. An AAV serotype-specific immune tolerance could be successfully established, which enabled repeated, that is, second and third, systemic administration of AAV vectors in the same mice. A combination of CTLA4-Ig and CD40-Ig delivered via AAV vectors significantly inhibited T and B cell activations without affecting the immune response to the total immunoglobulin G production and cytokines. Interestingly, exogenous gene expression significantly improved after multiple administrations of AAV vector in vivo. Our study generates a reliable and effective method for repeated dosing of AAV vectors that is needed on gene therapy.

中文翻译：

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在阻断 T 细胞共刺激途径后，在免疫活性小鼠中反复全身给药腺相关病毒载体

中和抗体 (NAb) 强烈限制腺相关病毒 (AAV) 载体转导和重复给药。先前的研究表明，AAVs 诱导的 NAbs 与 T 细胞和 B 细胞活化有关，并且涉及 B7/CD28 和 CD40/CD40L 共刺激信号通路。细胞毒性 T 淋巴细胞相关抗原 4 (CTLA4) 和 CD40 是参与共刺激途径的重要分子。在这项研究中，我们通过 AAV 评估了 CTLA4-Ig 和 CD40-Ig 免疫抑制功效，并研究了它们对 AAV 载体多系统给药可行性的影响。结果表明，单次施用单独携带 CTLA4-Ig 或与 CD40-Ig 一起的 AAV 载体可以大大降低 NAbs 的水平。可以成功建立 AAV 血清型特异性免疫耐受，这使得能够在同一只小鼠中重复，即第二次和第三次全身施用 AAV 载体。通过 AAV 载体递送的 CTLA4-Ig 和 CD40-Ig 的组合显着抑制了 T 和 B 细胞活化，而不影响对总免疫球蛋白 G 产生和细胞因子的免疫反应。有趣的是，多次施用 AAV 载体后外源基因表达显着改善在体内。我们的研究产生了一种可靠且有效的方法，用于重复给予基因治疗所需的 AAV 载体。