Kim Yun-Gon, Gil Geun-Cheol, Harvey David J, Kim Byung-Gee
Interdisciplinary Program for Biochemical Engineering and Biotechnology, Seoul National University, Seoul, Korea.
Proteomics. 2008 Jul;8(13):2596-610. doi: 10.1002/pmic.200700972.
The major barrier in transplantation of pig organs into humans is the presence of surface carbohydrate antigens (e.g., the Gal alpha 1-3 Gal beta 1-4GlcNAc-R (alpha-Gal) epitope) expressed on pig endothelial cells. In this study, total N-glycans from membrane glycoproteins derived from specific pathogen-free miniature pig kidney are identified by MALDI-TOF, negative ion ESI MS/MS and normal-phase HPLC (NP-HPLC) combined with exoglycosidase digestion. Over 100 N-glycans, including sialylated and neutral types, were identified. As well as the known alpha-Gal antigens, some of these glycans contained novel non-Gal carbohydrate antigens such as (Neu5Gc-Gal-GlcNAc) and Gal alpha 1-3 Lewis(x) (Gal-Gal-(Fuc)GlcNAc) which have not been reported before in N-glycans from pig organs. The ability of MALDI, ESI, and HPLC to measure the relative proportions of the glycans was evaluated. The HPLC resolution was insufficient for accurate work and some minor differences were noted in the ionization efficiencies of different glycan groups when measured by the two mass spectrometric techniques. However, the results indicated that the relative quantity of alpha-Gal epitope was in the region of 50% of the complex glycans. High-mannose type glycans were also abundant (35-43%) but appeared to be ionized more efficiently than the complex glycans by ESI than by MALDI.
将猪器官移植到人类体内的主要障碍是猪内皮细胞表面存在的碳水化合物抗原（例如，Galα1-3Galβ1-4GlcNAc-R（α-Gal）表位）。在本研究中，通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF）、负离子电喷雾串联质谱（ESI MS/MS）和正相高效液相色谱（NP-HPLC）结合外切糖苷酶消化，鉴定了来自无特定病原体小型猪肾脏的膜糖蛋白中的总N-聚糖。鉴定出了100多种N-聚糖，包括唾液酸化型和中性型。除了已知的α-Gal抗原外，其中一些聚糖还含有新的非Gal碳水化合物抗原，如（Neu5Gc-Gal-GlcNAc）和Galα1-3Lewis(x)（Gal-Gal-(Fuc)GlcNAc），这些抗原以前在猪器官的N-聚糖中尚未见报道。评估了MALDI、ESI和HPLC测量聚糖相对比例的能力。HPLC的分辨率不足以进行精确分析，并且在用两种质谱技术测量时，不同聚糖组的电离效率存在一些细微差异。然而，结果表明，α-Gal表位的相对含量在复合聚糖的50%左右。高甘露糖型聚糖也很丰富（35-43%），但通过ESI电离似乎比通过MALDI电离更有效。
