Structural Characterization of Glycans on Omega-1, a Major Schistosoma mansoni Egg Glycoprotein That Drives Th2 Responses

• Published in: Journal of proteome research Vol. 9; no. 5; pp. 2630 - 2642
• Main Authors: Meevissen, Moniek H. J, Wuhrer, Manfred, Doenhoff, Michael J, Schramm, Gabriele, Haas, Helmut, Deelder, André M, Hokke, Cornelis H
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 07.05.2010
• Subjects: alpha-L-Fucosidase - metabolism; Animals; Antigens, Helminth - chemistry; Antigens, Helminth - immunology; beta-Galactosidase - metabolism; Egg Proteins - chemistry; Egg Proteins - immunology; Egg Proteins - metabolism; Glycoproteins - chemistry; Glycoproteins - immunology; Glycoproteins - metabolism; Glycosylation; Immunity, Humoral - drug effects; Peptide Fragments - analysis; Peptide Fragments - metabolism; Polysaccharides - analysis; Polysaccharides - immunology; Polysaccharides - metabolism; Schistosoma mansoni - chemistry; Schistosoma mansoni - immunology; Tandem Mass Spectrometry; Th2 Cells - drug effects; Th2 Cells - immunology; Trypsin - metabolism; Schistosoma mansoni; Lewis X; glycosylation; omega-1
• ISSN: 1535-3893; 1535-3907
• 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.