title: A major Echinococcus multilocularis antigen is a mucin-type glycoprotein.
abstract: The metacestode of Echinococcus multilocularis is surrounded by a carbohydrate-rich laminated layer, which plays a key role in the establishment of the infection in the mammalian host. A major component of the laminated layer is an antigen referred to as Em2(G11). This highly species-specific antigen has been used for serodiagnoses of alveolar echinococcosis and is suggested to contain carbohydrates as major constituents. The results of this work have shown that immunoaffinity-purified Em2(G11) subjected to size-exclusion chromatography eluted mainly in the void volume, indicating a high molecular weight structure of this antigen. Amino acid analysis revealed a large proportion of threonine and proline residues in Em2(G11). The carbohydrate moiety of the antigen was found to be composed of galactose, N-acetylgalactosamine, and N-acetylglucosamine with a ratio of 2.4:1.0:0.5 as determined by gas-chromatography/mass spectrometry. An isotope tag was introduced to the beta-eliminated glycans, and an integrated mass spectrometric O-glycan profiling and sequencing approach was employed to obtain detailed sequence and linkage information of the unseparated glycoform pool. Novel glycoforms containing mucin-type core Gal1-3GalNAc and branched core structures attached to both serine and threonine residues are described. The data presented reveal that the Em2(G11) antigen is a mucin-type glycosylated protein.
authors.affiliation: Institute of Parasitology, University of Zurich, Winterthurerstrasse 266a, 8057 Zurich, Switzerland.
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Hülsmeier
authors.forename: Peter M
authors.initials: PM
authors.lastname: Gehrig
authors.forename: Rudolf
authors.initials: R
authors.lastname: Geyer
authors.forename: Ragna
authors.initials: R
authors.lastname: Sack
authors.forename: Bruno
authors.initials: B
authors.lastname: Gottstein
authors.forename: Peter
authors.initials: P
authors.lastname: Deplazes
authors.forename: Peter
authors.initials: P
authors.lastname: Köhler
mesh_terms: D000818:Animals; D000947:Antigens, Helminth / Q000737:chemistry*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000032:analysis; D002850:Chromatography, Gel; D004446:Echinococcus / Q000276:immunology*; D015801:Helminth Proteins / Q000737:chemistry* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009077:Mucins / Q000737:chemistry*; D009844:Oligosaccharides / Q000737:chemistry* / Q000302:isolation & purification; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000947:Antigens, Helminth; D002241:Carbohydrates; C115843:Em6 protein, Echinococcus multilocularis; D015801:Helminth Proteins; D009077:Mucins; D009844:Oligosaccharides