人抗猪异种抗原糖表位的探讨

Study on the carbohydrate epitope structure of porcine xenoantigens recognized by human natural antibodies

对猪血管内皮细胞表面异种抗原糖受体表位进行研究。用4个糖结合物中和人天然抗体,经中和后的人血清再与猪血管内皮细胞行补体依赖的细胞毒反应(MTT法)。牛血清白蛋白为阴性对照。N-乳四糖、H血型物质及猪胃粘膜粗提液能中和人大然抗体,它们均含有Gal(β1,3)GlcNAc。猪胃粘膜粗提液显示出极强的中和作用,它的主要结构为GlcNAc(α1,4)Gal。用唾液酸复盖这些有效基因,则糖结合物失去中和人天然抗体的作用。而用岩藻糖复盖有效基因却没有上述影响,提示糖结合物的外部结构颇为重要。

In order to determine the carbohydraic (CH) epitopes recognized by human natural antibodies (Ab) on membrane glycoproteins of porcine endothelial cells (EC), glyeoconjugates (GC) were synthesized by coupling CH residues to bovine serum albumin (BSA) using the reductive amination method. The glycoconjugates obtained and porcine gastric mucin were incubated at various concentrations with decomplemented human serus in order to neutralize human anti-pig Ab. The cytotoxie activity of these sera to pig EC was then assessed using a complement-dependent cytotoxicity test (MTT method). Lacto-N tetraose, H blood substance and porcine gastric muein could inhibit cytoxicity versus BSA alone. Porcine gastric mucin exhibiting the strongest inhibitory activity contains GlcNAc (α1,4) Gal sequences. However, the other inhibitors of EC lysis bear Gal (β1,3) GIcNAc sequences. The lack of inhibition by sialylated similar sequences suggests that the external position of GC is important.