Immune mediated graft loss still represents a major risk to transplant recipients. Creative approaches to immunosuppression that exploit the recipient's own alloregulatory mechanisms could reduce the need for pharmacologic immunosuppression and potentially induce immune tolerance. In the process of studying recipient derived myeloid derived suppressor cells (MDSCs), we identified key alloregulatory MDSC mechanisms, mediated by isolatable proteins IL-4, IL-34, and IL-10. We sought to purify these proteins and fuse them for subsequent infusion into transplant recipients as a means of inducing an alloregulatory response. In this introductory investigation, we leveraged molecular engineering technology to create a fusion protein (FP) of three cytokine coding sequences of IL-4, IL-34, and IL-10 and demonstrated their expressions by Western Blot analysis. Following purification, we tested whether FP IL-4/IL-34/IL-10 (FP1) can protect heart transplant allografts. Injection of FP1 significantly prolonged allogeneic cardiac graft survival in a dose-dependent fashion and the increase of graft survival time exceeded survival attributable to IL-34 alone. In vitro, MDSCs cells were expanded by FP1 treatment. However, FP1 did not directly inhibit T cell proliferation in vitro. In conclusion, newly developed FP1 improves the graft survival in cardiac transplantation mouse model. Significant additional work to optimize FP1 or include other novel proteins could supplement current treatment options for transplant patients.

中文翻译：

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初步探索一种新型融合蛋白 IL-4/IL-34/IL-10，通过同种异体调节促进心脏同种异体移植小鼠的存活。

免疫介导的移植物丢失仍然是移植受者的主要风险。利用受体自身同种调节机制的创造性免疫抑制方法可以减少对药物免疫抑制的需求，并可能诱导免疫耐受。在研究受体源性骨髓源性抑制细胞 (MDSC) 的过程中，我们确定了由可分离蛋白 IL-4、IL-34 和 IL-10 介导的关键同种调节 MDSC 机制。我们试图纯化这些蛋白质并将它们融合，以便随后输注到移植受者体内，作为诱导同种调节反应的一种手段。在这项介绍性研究中，我们利用分子工程技术创建了 IL-4、IL-34 和 IL-10 三种细胞因子编码序列的融合蛋白 (FP)，并通过蛋白质印迹分析证明了它们的表达。纯化后，我们测试了 FP IL-4/IL-34/IL-10 (FP1) 是否可以保护同种异体心脏移植物。注射FP1以剂量依赖性方式显着延长同种异体心脏移植物的存活时间，并且移植物存活时间的增加超过单独使用IL-34所致的存活时间。在体外，MDSCs 细胞通过 FP1 处理进行扩增。然而，FP1在体外并不能直接抑制T细胞增殖。总之，新开发的 FP1 提高了心脏移植小鼠模型的移植物存活率。优化 FP1 或包含其他新型蛋白质的大量额外工作可以补充移植患者当前的治疗选择。