Corneal blindness affects more than 5 million individuals, with over 180,000 corneal transplantations (CTs) performed annually. In high-risk CTs, almost all grafts are rejected within 10 years. Here, we investigated adeno-associated virus (AAV) ex vivo gene therapy to establish immune tolerance in the corneal allograft to prevent high-risk CT rejection. Our previous work has demonstrated that HLA-G contributes to ocular immune privilege by inhibiting both immune cells and neovascularization; however, homodimerization is a rate-limiting step for optimal HLA-G function. Therefore, a chimeric protein called single-chain immunomodulator (scIM), was engineered to mimic the native activity of the secreted HLA-G dimer complex and eliminate the need for homodimerization. In a murine corneal burn model, AAV8-scIM significantly reduced corneal vascularization and fibrosis. Next, ex vivo AAV8-scIM gene delivery to corneal allografts was evaluated in a high-risk CT rejection rabbit model. All scIM-treated corneas were well tolerated and transparent after 42 days, while 83% of vehicle-treated corneas were rejected. Histologically, AAV-scIM-treated corneas were devoid of immune cell infiltration and vascularization, with minimal fibrosis at the host-graft interface. The data collectively demonstrate that scIM gene therapy prevents corneal neovascularization, reduces trauma-induced corneal fibrosis, and prevents allogeneic CT rejection in a high-risk large animal model.

中文翻译：

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嵌合抗血管化免疫调节剂通过离体基因治疗预防高危角膜移植排斥反应


角膜盲影响超过 500 万人，每年进行超过 180,000 例角膜移植 （CT）。在高危 CT 中，几乎所有移植物都在 10 年内被排斥。在这里，我们研究了腺相关病毒 （AAV） 离 体基因治疗，以建立角膜同种异体移植物的免疫耐受，以防止高危 CT 排斥反应。我们之前的工作已经证明，HLA-G 通过抑制免疫细胞和新生血管形成来促进眼部免疫特权;然而，同源二聚化是实现最佳 HLA-G 功能的限速步骤。因此，一种称为单链免疫调节剂 （scIM） 的嵌合蛋白被设计成模拟分泌的 HLA-G 二聚体复合物的天然活性，并消除了同源二聚化的需要。在小鼠角膜烧伤模型中，AAV8-scIM 显着减少了角膜血管形成和纤维化。接下来，在高危 CT 排斥兔模型中评估离 体 AAV8-scIM 基因递送到角膜同种异体移植物。42 天后，所有 scIM 处理的角膜都具有良好的耐受性和透明性，而 83% 的载体处理的角膜被排斥。在组织学上，AAV-scIM 处理的角膜没有免疫细胞浸润和血管形成，宿主-移植物界面的纤维化最小。数据共同表明，scIM 基因疗法可防止角膜新生血管形成，减少创伤诱导的角膜纤维化，并防止高危大型动物模型中的同种异体 CT 排斥反应。