α1,3-半乳糖基转移酶基因敲除猪的纤连蛋白是一种异种抗原。
Fibronectin from alpha 1,3-galactosyltransferase knockout pigs is a xenoantigen.
机构信息
Indiana University School of Medicine, Indianapolis, Indiana.
出版信息
J Surg Res. 2013 Oct;184(2):1123-33. doi: 10.1016/j.jss.2013.04.012. Epub 2013 Apr 28.
BACKGROUND
Antibody-mediated rejection continues to be an obstacle for xenotransplantation despite development of α1,3-galactosyltransferase knockout (GTKO) pigs. Fibronectin (Fn) from GTKO pigs was identified as a xenoantigen in baboons. N-glycolylneuraminic acid (Neu5Gc), similar to galactose α1,3-galactose, is an antigenic carbohydrate found in pigs. We evaluated human antibody reactivity and performed initial antigenic epitope characterization of Fn from GTKO pigs.
MATERIALS AND METHODS
GTKO pig aortic endothelial cells (AEC) were isolated and assessed for antibody-mediated complement-dependent cytotoxicity (CDC). Human and GTKO pig Fn were purified and analyzed using immunoblots. GTKO pig and human AEC absorbed human sera were assessed for CDC and anti-GTKO pig Fn antibodies. GTKO pig proteins were assessed for Neu5Gc. Immunoaffinity-purified human IgG anti-GTKO pig (hIgG-GTKOp) Fn using a GTKO pig Fn column were evaluated for cross-reactivity with other proteins.
RESULTS
GTKO pig AEC had greater human antibody binding, complement deposition and CDC compared with allogeneic human AEC. Human sera absorbed with GTKO pig AEC resulted in diminished anti-GTKO pig Fn antibody. Neu5Gc was identified on GTKO pig Fn and other proteins. The hIgG-GTKOp Fn cross-reacted with multiple GTKO pig proteins and was enriched with anti-Neu5Gc antibody.
CONCLUSIONS
Removal of antigenic epitopes from GTKO pig AEC would improve xenograft compatibility. GTKO pig Fn has antigenic epitopes, one identified as Neu5Gc, which may be responsible for pathology and cross-reactivity of hIgG-GTKOp Fn. Genetic knockout of Neu5Gc appears necessary to address significance and identification of non-Neu5Gc GTKO pig Fn antigenic epitopes.
背景
尽管开发了α1,3-半乳糖基转移酶敲除（GTKO）猪，但抗体介导的排斥反应仍然是异种移植的障碍。GTKO 猪的纤连蛋白（Fn）被鉴定为狒狒的异种抗原。N-糖基神经氨酸（Neu5Gc）与半乳糖α1,3-半乳糖相似，是一种存在于猪中的抗原性碳水化合物。我们评估了人抗体的反应性，并对 GTKO 猪 Fn 的初始抗原表位进行了表征。
材料与方法
分离 GTKO 猪主动脉内皮细胞（AEC）并评估其抗体介导的补体依赖性细胞毒性（CDC）。纯化人源和 GTKO 猪 Fn 并进行免疫印迹分析。评估 GTKO 猪和人 AEC 吸收人血清后的 CDC 和抗 GTKO 猪 Fn 抗体。评估 GTKO 猪蛋白中的 Neu5Gc。使用 GTKO 猪 Fn 柱对免疫亲和纯化的人抗 GTKO 猪（hIgG-GTKOp）Fn 进行评价，以评估其与其他蛋白的交叉反应性。
结果
与同种异体人 AEC 相比，GTKO 猪 AEC 具有更高的人抗体结合、补体沉积和 CDC。用 GTKO 猪 AEC 吸收的人血清导致抗 GTKO 猪 Fn 抗体减少。在 GTKO 猪 Fn 和其他蛋白上发现了 Neu5Gc。hIgG-GTKOp Fn 与多种 GTKO 猪蛋白发生交叉反应，并富集了抗 Neu5Gc 抗体。
结论
从 GTKO 猪 AEC 中去除抗原表位将提高异种移植物的相容性。GTKO 猪 Fn 具有抗原表位，其中一个被鉴定为 Neu5Gc，这可能是导致 hIgG-GTKOp Fn 发生病理和交叉反应的原因。Neu5Gc 的基因敲除似乎是解决非 Neu5Gc GTKO 猪 Fn 抗原表位的重要性和鉴定所必需的。
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