Structural characterization of N-glycans from the freshwater snail Biomphalaria glabrata cross-reacting with Schistosoma mansoni glycoconjugates

Abstract

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(a1-3)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.

Polysaccharide Capsule Composition of Pneumococcal Serotype 19A Subtypes Is Unaltered among Subtypes and Independent of the Nutritional Environment

“…GC-MS. Gas chromatography-mass spectrometry (GC-MS) analysis of alditol acetates of the polysaccharide hydrolysates from strains 109.44 grown in PIM and 501.24 grown in PIM, pooled saliva, and CDM glucose was performed as a control, as previously described (37,38).…”

Analysis of carbohydrates and glycoconjugates by matrix‐assisted laser desorption/ionization mass spectrometry: An update for 2007–2008

“…N-Linked glycans from non-mammalian species. One hundred and sixteen complex and paucimannosidic glycans have been identified in the freshwater snail (Biomphalaria glabrata) (Lehr et al, 2007). Some carried 3-OMe-mannose.…”

Revealing the anti-HRP epitope in Drosophila and Caenorhabditis

“…Squid rhodopsin has been found to carry core α1-3-fucose [74], as have Nglycans from various gastropod species [75,76], although some snail species have xylosylated, but not core α1-3-fucosylated, N-glycans [77,78]. Also, the trematode parasites, particularly Schistosoma spp., express both xylose and core α1-3-fucose residues, which is interesting from the perspective that their snail intermediate hosts also have such glycans and that schistosome N-glycans play a role in T-cell (Th2) responses to the parasite [79].…”