Glycomics Analysis of Schistosoma mansoni Egg and Cercarial Secretions

Abstract

The parasitic helminth Schistosoma mansoni is a major public health concern in many developing countries. Glycoconjugates, and in particular the carbohydrate component of these products, represent the main immunogenic challenge to the host and could therefore represent one of the crucial determinants for successful parasite establishment. Here we report a comparative glycomics analysis of the N-and O-glycans derived from glycoproteins present in S. mansoni egg (egg-secreted protein) and cercarial (0 -3-h released protein) secretions by a combination of mass spectrometric techniques. Our results show that S. mansoni secrete glycoproteins with glycosylation patterns that are complex and stage-specific. Cercarial stage secretions were dominated by N-glycans that were core-xylosylated, whereas N-glycans from egg secretions were predominantly core-difucosylated. O-Glycan core structures from cercarial secretions primarily consisted of the core sequence Gal␤133(Gal␤136)GalNAc, whereas egg-secreted O-glycans carried the mucin-type core 1 (Gal␤133GalNAc) and 2 (Gal␤133(GlcNAc␤136)GalNAc) structures. Additionally we identified a novel O-glycan core in both secretions in which a Gal residue is linked to the protein. Terminal structures of N-and O-glycans contained high levels of fucose and include stage-specific structures. These glycan structures identified in S. mansoni secretions are potentially antigenic motifs and ligands for carbohydrate-binding pro-

Identification of Antigenic Glycans from Schistosoma mansoni by Using a Shotgun Egg Glycan Microarray

“…Thus, the results indicate that there was not appreciable contamination of the SSGM with mouse-derived glycans and that the schistosome GAEABs separated by the 1D HPLC were recognized primarily by mannoseand fucose-binding lectins. The minimally purified glycans at this stage represent the PNGase F/A-releasable N-glycome and are consistent with previous studies showing the presence of a variety of fucosylated and mannosylated N-glycans in schistosome eggs, miracidia, and egg secretions (27)(28)(29)49). The development of this array indicates that our methods of isolation and tagging of glycans generate a glycan library that is representative of the N-glycome of S. mansoni, and its interrogation can point to immunologically relevant fractions.…”

“…These global profiling studies have confirmed the major glycan structures previously identified and provided new information on the diversity of glycans and the heterogeneity found among the life stages of the parasite and their secretions (27,(29)(30)(31). Several studies also have demonstrated the feasibility of profiling schistosome glycans using various microarray printing technologies and probing with glycan-binding proteins, antibodies, and antisera, demonstrating that such techniques can be powerful tools for profiling the immune response to this disease (26,(32)(33)(34) and the development or characterization of novel anti-glycan reagents.…”

“…2 and is described in Materials and Methods. N-glycans were released by consecutive treatments with PNGase F and PNGase A based on previous studies showing the presence of core ␣3-fucose in schistosome egg glycans (27)(28)(29)49). PNGase F treatment releases Nglycans that lack ␣3-fucosylation in the chitobiosyl core, but susceptible glycans may be ␣6-fucosylated and ␤-xylosylated in their cores.…”

Helminth infections: the great neglected tropical diseases

“…Proteomic investigations have also revealed differences between the secretome of Trichinella spiralis and that of Trichinella pseudospiralis (129) as well as the plasticity of the proteome of gutdwelling nematodes in response to immunological pressure (130). Glycomics will provide information about the glycan structures of helminths that are known to mediate and modulate host immunological responses to these parasites (131,132). Moreover, techniques from developmental biology and other disciplines, such as whole mount in situ hybridization (WISH) and gene microarrays, have now been established as crucial tools for investigating the function of helminth genes and proteins (133)(134)(135).…”

Contribution of myeloid cell subsets to liver fibrosis in parasite infection

“…In addition, a comparison of the surface marker phenotype and a better definition of the M2 gene subsets that are expressed by myeloid cells elicited in distinct organs, including skin, liver, intestine and lungs, in parasite-infected hosts is required. Moreover, since schistosome products interact with TLRs and CLRs [116, [165][166][167], it will be instructive to determine whether differences in expression of TLRs and CLRs by macrophages, DCs and eosinophils contribute to their distinct function.…”