Department of Parasitology, Leiden University Medical Centre, 2333 ZA Leiden, The Netherlands.
J Proteome Res. 2010 May 7;9(5):2630-42. doi: 10.1021/pr100081c.
Soluble egg antigens (SEA) of the human parasite Schistosoma mansoni are among the strongest natural stimuli of Th2 responses. Omega-1, a major glycoprotein in SEA, initiates these characteristic Th2 responses through conditioning of dendritic cells (DCs). In view of the reported immunomodulatory potential of SEA glycans, we have investigated omega-1 glycosylation, using an approach combining mass spectrometric techniques and enzyme treatments at the glycopeptide level. We demonstrate that omega-1 has two fully occupied N-glycosylation sites, each mainly carrying core-difucosylated diantennary glycans with one or more Lewis X motifs in the antennae. Using a specific approach of nanoscale LC-MS(/MS) and MALDI-TOF(/TOF) MS in combination with exoglycosidase treatments of tryptic glycopeptides, we were able to provide a detailed, site-specific glycosylation analysis of a single, native S. mansoni glycoprotein. The obtained knowledge of the glycans present on omega-1 contributes to a full understanding of the mode of action of this immunomodulatory glycoprotein.
曼氏血吸虫可溶性虫卵抗原（SEA）是最强的天然 Th2 反应刺激物之一。SEA 中的主要糖蛋白 omega-1 通过对树突状细胞（DC）的调理作用引发这些特征性的 Th2 反应。鉴于 SEA 糖缀合物的报道的免疫调节潜力，我们使用结合了质谱技术和糖肽水平的酶处理的方法研究了 omega-1 的糖基化。我们证明 omega-1 有两个完全被占据的 N-糖基化位点，每个位点主要携带核心二岩藻糖基化的二天线型聚糖，天线中带有一个或多个 Lewis X 基序。使用纳米级 LC-MS(/MS) 和 MALDI-TOF(/TOF) MS 与胰蛋白酶糖肽的外糖苷酶处理的特定方法相结合，我们能够对单个天然的曼氏血吸虫糖蛋白进行详细的、位点特异性的糖基化分析。关于 omega-1 上存在的聚糖的知识有助于全面了解这种免疫调节糖蛋白的作用模式。
