Lehr Tobias, Geyer Hildegard, Maass Kai, Doenhoff Michael J, Geyer Rudolf
Institute of Biochemistry, Faculty of Medicine, University of Giessen, Friedrichstrasse 24, D-35392 Giessen, Germany.
Glycobiology. 2007 Jan;17(1):82-103. doi: 10.1093/glycob/cwl048. Epub 2006 Sep 13.
The human parasitic trematode Schistosoma mansoni has a complex life cycle that includes the freshwater snail Biomphalaria glabrata as intermediate host. Within each stage, the parasite synthesizes a wide array of glycoconjugates, exhibiting, in part, unique carbohydrate structures. In addition, the parasite expresses definitive host-like sugar epitopes, such as Lewis X determinants, supporting the concept of carbohydrate-mediated molecular mimicry as an invasion and survival strategy. In the present study, we investigated whether common carbohydrate determinants occur also at the level of the intermediate host. To this end, a structural characterization of hemolymph glycoprotein-N-glycans of B. glabrata was performed. N-glycans were released from tryptic glycopeptides and labeled with 2-aminopyridine. Sugar chains serologically cross-reacting with S. mansoni glycoconjugates were isolated by immunoaffinity chromatography using a polyclonal antiserum directed against schistosomal egg antigens and fractionated by Aleuria aurantia lectin affinity chromatography and high-performance liquid chromatography. Obtained glycans were analyzed by different mass spectrometric techniques as well as by monosaccharide constituent and linkage analysis. The results revealed a highly heterogeneous oligosaccharide pattern. Cross-reacting species represented about 5% of the total glycans and exhibited a terminal Fuc(alpha1-3)GalNAc unit, a (1-2)-linked xylosyl residue, or both types of structural motifs. In conclusion, our study demonstrates the presence of common carbohydrate epitopes also at the level of S. mansoni and its intermediate host.
人类寄生吸虫曼氏血吸虫具有复杂的生命周期，其中包括淡水螺光滑双脐螺作为中间宿主。在每个阶段，该寄生虫都会合成大量糖缀合物，部分呈现出独特的碳水化合物结构。此外，该寄生虫还表达类似终末宿主的糖表位，如Lewis X决定簇，这支持了碳水化合物介导的分子模拟作为一种侵袭和生存策略的概念。在本研究中，我们调查了常见的碳水化合物决定簇是否也存在于中间宿主层面。为此，我们对光滑双脐螺血淋巴糖蛋白的N-聚糖进行了结构表征。从胰蛋白酶糖肽中释放出N-聚糖，并用2-氨基吡啶进行标记。使用针对血吸虫卵抗原的多克隆抗血清，通过免疫亲和色谱法分离与曼氏血吸虫糖缀合物发生血清学交叉反应的糖链，并通过橙黄网柄菌凝集素亲和色谱法和高效液相色谱法进行分级分离。通过不同的质谱技术以及单糖组成和连接分析对所得聚糖进行分析。结果显示出高度异质的寡糖模式。交叉反应物种约占总聚糖的5%，并呈现出末端Fuc(α1-3)GalNAc单元、(1-2)连接的木糖基残基或两种结构基序。总之，我们的研究表明在曼氏血吸虫及其中间宿主层面也存在常见的碳水化合物表位。
