Nyame A K, Debose-Boyd R, Long T D, Tsang V C, Cummings R D
Department of Biochemistry and Molecular Biology, University of Oklahoma Health Science Center, BRC 417, 975 N.E. 10th Street, Oklahoma City, OK 73104, USA.
Glycobiology. 1998 Jun;8(6):615-24. doi: 10.1093/glycob/8.6.615.
Adults of the human parasitic trematode Schistosoma mansoni, which causes hepatosplenic/intestinal complications in humans, synthesize glycoconjugates containing the Lewis x (Lex) Galbeta1-->4(Fucalpha1-->3)GlcNAcbeta1-->R, but not sialyl Lewis x (sLex), antigen. We now report on our analyses of Lexand sLexexpression in S.haematobium and S.japonicum, which are two other major species of human schistosomes that cause disease, and the possible autoimmunity to these antigens in infected individuals. Antigen expression was evaluated by both ELISA and Western blot analyses of detergent extracts of parasites using monoclonal antibodies. Several high molecular weight glycoproteins in both S. haematobium and S. japonicum contain the Lexantigen, but no sialyl Lexantigen was detected. In addition, sera from humans and rodents infected with S.haematobium and S.japonicum contain antibodies reactive with Lex. These results led us to investigate whether Lexantigens are expressed in other helminths, including the parasitic trematode Fasciola hepatica , the parasitic nematode Dirofilaria immitis (dog heartworm), the ruminant nematode Haemonchus contortus , and the free-living nematode Caenorhabditis elegans . Neither Lexnor sialyl-Lexis detectable in these other helminths. Furthermore, none of the helminths, including schistosomes, express Lea, Leb, Ley, or the H-type 1 antigen. However, several glycoproteins from all helminths analyzed are bound by Lotus tetragonolobus agglutinin , which binds Fucalpha1-->3GlcNAc, and Wisteria floribunda agglutinin, which binds GalNAcbeta1-->4GlcNAc (lacdiNAc or LDN). Thus, schistosomes may be unique among helminths in expressing the Lexantigen, whereas many different helminths may express alpha1,3-fucosylated glycans and the LDN motif.
人寄生虫曼氏血吸虫的成虫会导致人类出现肝脾/肠道并发症，它能合成含有路易斯X（Lex）[β-D-半乳糖-1,4-(α-L-岩藻糖-1,3)-N-乙酰葡糖胺-β-1-R]的糖缀合物，但不合成唾液酸化路易斯X（sLex）抗原。我们现在报告对埃及血吸虫和日本血吸虫中Lex和sLex表达的分析，这是另外两种会引发疾病的主要人体血吸虫，以及受感染个体对这些抗原可能产生的自身免疫反应。通过使用单克隆抗体对寄生虫去污剂提取物进行ELISA和蛋白质印迹分析来评估抗原表达。埃及血吸虫和日本血吸虫中的几种高分子量糖蛋白都含有Lex抗原，但未检测到唾液酸化Lex抗原。此外，感染埃及血吸虫和日本血吸虫的人和啮齿动物的血清中含有与Lex反应的抗体。这些结果促使我们研究Lex抗原是否在其他蠕虫中表达，包括寄生吸虫肝片吸虫、寄生线虫犬恶丝虫（犬心丝虫）、反刍动物线虫捻转血矛线虫和自由生活线虫秀丽隐杆线虫。在这些其他蠕虫中均未检测到Lex或唾液酸化Lex。此外，包括血吸虫在内的所有蠕虫均不表达Lea、Leb、Ley或H-1型抗原。然而，所有分析的蠕虫中的几种糖蛋白都能与结合α-L-岩藻糖-1,3-N-乙酰葡糖胺的四棱豆凝集素和结合β-D-半乳糖胺-1,4-N-乙酰葡糖胺（乳糖二糖胺或LDN）的紫藤凝集素结合。因此，血吸虫在表达Lex抗原方面可能在蠕虫中是独特的，而许多不同的蠕虫可能表达α1,3-岩藻糖基化聚糖和LDN基序。
