Diamond L E, McCurry K R, Oldham E R, Tone M, Waldmann H, Platt J L, Logan J S
DNX Biotherapeutics Inc., Princeton, New Jersey 08540, USA.
Transpl Immunol. 1995 Dec;3(4):305-12. doi: 10.1016/0966-3274(95)80016-6.
Porcine-to-human xenotransplantation offers a potential solution to the critical shortage of human organs. The major immunological barrier to xenotransplantation between these species is a rapid rejection process mediated by preformed natural antibodies and complement. Xenogeneic organ grafts are especially susceptible to complement mediated injury because complement regulatory proteins, which ordinarily protect cells from inadvertent injury during the activation of complement, function poorly in regulating activation of heterologous complement. Removal of xenoreactive antibodies or systemic inhibition of complement activity has been shown to prolong graft survival. As an alternative to the systemic inhibition of complement activity, we have established a model system using transgenic animals to test whether the expression of human membrane bound complement regulatory proteins on mouse endothelial cells can inhibit the activation of human complement. CD59, which acts at the terminal stage of complement activation by inhibiting the formation of the membrane attack complex, was used as a paradigm for this model. A CD59 construct containing the putative CD59 gene promoter linked to the CD59 coding region was used to demonstrate expression of the human CD59 protein in various tissues of transgenic mice, including endothelial cells in the heart. In addition, we show that the transgenic CD59 protein is biologically active as determined by the ability to inhibit the formation of membrane attack complex in transgenic mouse hearts perfused ex vivo with human plasma. These results demonstrate that expression of membrane bound complement regulatory proteins can achieve complement inhibition in a xenogeneic organ and suggest that this approach may be useful for successful xenotransplantation between discordant species.
猪到人的异种移植为人体器官严重短缺提供了一种潜在的解决方案。这些物种之间异种移植的主要免疫障碍是由预先形成的天然抗体和补体介导的快速排斥过程。异种器官移植特别容易受到补体介导的损伤，因为补体调节蛋白在调节异源补体激活方面功能不佳，而补体调节蛋白通常可保护细胞在补体激活过程中免受意外损伤。已证明去除异种反应性抗体或全身性抑制补体活性可延长移植物存活时间。作为全身性抑制补体活性的替代方法，我们建立了一个使用转基因动物的模型系统，以测试小鼠内皮细胞上人类膜结合补体调节蛋白的表达是否能抑制人类补体的激活。CD59通过抑制膜攻击复合物的形成在补体激活的终末阶段起作用，被用作该模型的范例。一个包含推定的CD59基因启动子与CD59编码区相连的CD59构建体被用于证明人类CD59蛋白在转基因小鼠的各种组织中的表达，包括心脏中的内皮细胞。此外，我们表明，通过用人类血浆离体灌注转基因小鼠心脏时抑制膜攻击复合物形成的能力来确定，转基因CD59蛋白具有生物学活性。这些结果表明，膜结合补体调节蛋白的表达可以在异种器官中实现补体抑制，并表明这种方法可能有助于在不匹配物种之间成功进行异种移植。
