Lack of galactose-α-1,3-galactose expression on porcine endothelial cells prevents complement-induced lysis but not direct xenogeneic NK cytotoxicity
Lack of galactose-α-1,3-galactose expression on porcine endothelial cells prevents complement-induced lysis but not direct xenogeneic NK cytotoxicity
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DOI：
10.4049/jimmunol.172.10.6460
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发表时间：
2004-05-15
影响因子：
4.4
通讯作者：
Seebach, JD
中科院分区：
文献类型：
--
作者：
Baumann, BC;Forte, P;Seebach, JD
半乳糖-α-1，3-半乳糖（alphaGal）碳水化合物表位在猪细胞上表达，但在人细胞上不表达，因此代表了预先形成的人抗猪天然抗体（NAb）的主要靶标。基于猪-灵长类动物模型的结果，NAb与猪内皮细胞的结合可能会诱导猪-人异种移植中的补体激活、裂解和超急性排斥反应。人NK细胞也可通过直接识别靶细胞上的活化分子或通过Fc γ RIII介导的异种Ab依赖性细胞毒性（ADCC）来促进针对异种移植物的先天免疫应答。本研究解决了关于缺乏aGal是否保护猪内皮细胞免受NAb/补体诱导的裂解、直接异种NK裂解、NAb依赖性ADCC和剪切应力下人NK细胞的粘附的问题。同源重组、淘选和有限稀释克隆用于产生α Ga I阴性猪内皮细胞系，PED 2 *3.51。与α Ga I阳性表型相比，NAb/补体诱导的PED 2 *3.51的异种溶解平均减少86%。PED 2 *3.51抵抗NK细胞介导的ADCC，裂解减少30 - 70%。然而，由新鲜分离的或IL-2活化的人NK细胞或NK细胞系NK 92介导的PED 2 *3.51的直接异种溶解没有减少。此外，IL-2活化的人NK细胞的粘附不依赖于α Gal表达。总之，α Gal的去除导致补体诱导的裂解和ADCC的明显降低，但没有解决NK细胞的粘附和直接抗猪NK细胞毒性，表明α Gal不是针对猪细胞的直接人NK细胞毒性的主要靶标。
The galactose-alpha-1,3-galactose (alphaGal) carbohydrate epitope is expressed on porcine, but not human cells, and therefore represents a major target for preformed human anti-pig natural Abs (NAb). Based on results from pig-to-primate animal models, NAb binding to porcine endothelial cells will likely induce complement activation, lysis, and hyperacute rejection in pig-to-human xenotransplantation. Human NK cells may also contribute to innate immune responses against xenografts, either by direct recognition of activating molecules on target cells or by FcgammaRIII-mediated xenogeneic Ab-dependent cellular cytotoxicity (ADCC). The present study addressed the question as to whether the lack of aGal protects porcine endothelial cells from NAb/complement-induced lysis, direct xenogeneic NK lysis, NAb-dependent ADCC, and adhesion of human NK cells under shear stress. Homologous recombination, panning, and limiting dilution cloning were used to generate an alphaGaI-negative porcine endothelial cell line, PED2*3.51. NAb/complement-induced xenogeneic lysis of PED2*3.51 was reduced by an average of 86% compared with the alphaGaI-positive phenotype. PED2*3.51 resisted NK cell-mediated ADCC with a reduction of lysis ranging from 30 to 70%. However, direct xenogeneic lysis of PED2*3.51, mediated either by freshly isolated or IL-2-activated human NK cells or the NK cell line NK92, was not reduced. Furthermore, adhesion of IL-2-activated human NK cells did not rely on alphaGal expression. In conclusion, removal of alphaGal leads to a clear reduction in complement-induced lysis and ADCC, but does not resolve adhesion of NK cells and direct anti-porcine NK cytotoxicity, indicating that alphaGal is not a dominant target for direct human NK cytotoxicity against porcine cells.