Diswall M, Angström J, Schuurman H-J, Dor F J M F, Rydberg L, Breimer M E
Department of Surgery, Sahlgrenska University Hospital/campus Ostra, Göteborg, Sweden.
Transplant Proc. 2008 Mar;40(2):543-6. doi: 10.1016/j.transproceed.2008.01.032.
To avoid hyperacute rejection of xeno-organs, alpha1,3-galactosyltransferase knock-out (GalT-KO) pigs have been produced. However, Galalpha1,3Gal (Gal) determinant elimination may expose cryptic carbohydrate antigens and/or generate new antigens that might interfere with the human immune response.
Glycolipids isolated from small intestine and pancreas of two GalT-KO and one wild-type (WT) pig were tested for immune reactivity with antibodies on thin-layer chromatograms after separation by high-performance liquid chromatography, and selected fractions were analysed by proton NMR spectroscopy.
Immunostaining using purified human anti-Gal Abs revealed that tissues from WT animals express large amounts of Gal-antigens whereas GalT-KO tissues lacked these antigens. Proton NMR spectroscopy on small intestine fractions revealed both linear and branched nona- and decaglycosylceramides, respectively, with terminal Gal-epitopes. In corresponding GalT-KO fractions, Gal-epitopes seemed to be replaced by terminal alpha1,2fucoses. Two novel branched blood group H compounds was found in the GalT-KO intestine.
The structural complexity of alphaGal-terminating antigens in the WT organs is very high. Knockout of alpha1,3GalT by gene-targeting results in elimination of Gal-determinants. In addition structurally novel alpha1,2fucose-terminated blood group H compounds were identified in the GalT-KO tissue. These compounds are not expected to be recognized by the human immune system.
为避免对异种器官的超急性排斥反应，已培育出α1,3-半乳糖基转移酶基因敲除（GalT-KO）猪。然而，αGal1,3Gal（Gal）决定簇的消除可能会暴露隐藏的碳水化合物抗原和/或产生可能干扰人类免疫反应的新抗原。
从两只GalT-KO猪和一只野生型（WT）猪的小肠和胰腺中分离出糖脂，通过高效液相色谱分离后，在薄层色谱图上用抗体检测其免疫反应性，并对选定的馏分进行质子核磁共振光谱分析。
使用纯化的人抗Gal抗体进行免疫染色显示，野生型动物的组织表达大量Gal抗原，而GalT-KO组织缺乏这些抗原。对小肠馏分进行质子核磁共振光谱分析，分别发现了具有末端Gal表位的线性和分支的九糖基神经酰胺和十糖基神经酰胺。在相应的GalT-KO馏分中，Gal表位似乎被末端α1,2岩藻糖取代。在GalT-KO小肠中发现了两种新的分支血型H化合物。
野生型器官中以αGal结尾的抗原结构复杂性非常高。通过基因靶向敲除α1,3GalT可导致Gal决定簇的消除。此外，在GalT-KO组织中鉴定出了结构上新的以α1,2岩藻糖结尾的血型H化合物。预计这些化合物不会被人类免疫系统识别。
