Identification of a sialic acid containing glycocalyx on the surface of Schistosoma mansoni

McDiarmid, Shona S.; Podesta, Ron B.

doi:10.1016/0166-6851(84)90016-1

Cited by 19 publications

(4 citation statements)

References 37 publications

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“…sialoglycoproteins (Luft, 1976), and sulphated, or phosphate groups of polysaccharides (McDiarmid & Podesta, 1984). The present results were similar to the findings in other trematodes, such as Haematoloechus medioplexus (Rothman & Elder, 1970), F. hepatica (Threadgold, 1976), S. japonicum and S. mekongi (Sobhon & Upatham, 1990), and cestodes (Rothman & Elder, 1970;Lumsden, 1972), in which the parasite surfaces bore intense negatively charged acidic polysaccharides.…”

Section: Discussionsupporting

confidence: 90%

“…In S. mansoni, the negatively charged glycocalyx was thought to confer protection against the immune responses of the host, by reducing the adhesion of immuno-effector cells, and neutralizing the effects of complement (McDiarmid & Podesta, 1984). Furthermore, in newly excysted juveniles, the thick glycocalyx coating might assist in protecting the parasite against hydrolytic actions of the intestinal juice and bile.…”

Section: Discussionmentioning

confidence: 99%

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Opisthorchis viverrini: ultrastructure and cytochemistry of the glycocalyx of the tegument

et al. 2000

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The ultrastructure and cytochemistry of the glycocalyx of the tegument of Opisthorchis viverrini during maturation from newly excysted juvenile to adult stages were investigated using colloidal iron, ruthenium red and lectin stainings. The results showed that the glycocalyx was intensely stained by the first two dyes, thus indicating the presence of relatively high amounts of negative charges. However, the thickness and intensity of the staining decreased during the fluke's maturation. Binding studies using lectin probes on the surface of adult parasites showed that binding sites for Canavalia ensiformis (Con A), Triticum vulgaris (WGA) and Ricinus communis I (RCA I) were present in relative large amounts on the glycocalyx of the adult tegument, whereas those for Dolichos biflorus (DBA) were relatively fewer in number, and those for Ulex europaeus I (UEA I) were absent. The binding patterns of Con A, WGA, RCA I and DBA were generally similar, and the reaction product was uniformly distributed over the dorsal and ventral surfaces of the parasite's body. These bindings, therefore, indicate the presence of D-mannose/D-glucose, N-acetyl-Dglucosamine/sialic acid, D-galactose and N-acetyl-D-galactosamine residues on the glycocalyx of the adult tegument.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Opisthorchis viverrini: ultrastructure and cytochemistry of the glycocalyx of the tegument

et al. 2000

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“…The ligation of Siglec 8 on eosinophils (and Siglec 9 on neutrophils; von Gunten et al 2005) induces apoptosis (Nutku et al 2003), and the ability of helminths to trigger such a response would be to their benefit. The published literature on parasitic helminths possessing sialic acid-based glycoproteins is conflicting, with many studies suggesting that helminths do not synthesize them, and there is an equally convincing body of evidence demonstrating that sialic acid reactivity can be detected in worm extracts or ES products from many helminth species (McDiarmid and Podesta, 1984; Apinhasmit et al 2000; Elayoubi and Craig, 2004; Johnston, unpublished observations). We feel that this issue is deserving of clarity that will only come with additional well-controlled experimentation.…”

Section: Helminth Glycobiologymentioning

confidence: 99%

Parasitic helminths: a pharmacopeia of anti-inflammatory molecules

2008

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Infection with parasitic helminths takes a heavy toll on the health and well-being of humans and their domestic livestock, concomitantly resulting in major economic losses. Analyses have consistently revealed bioactive molecules in extracts of helminths or in their excretory/secretory products that modulate the immune response of the host. It is our view that parasitic helminths are an untapped source of immunomodulatory substances that, in pure form, could become new drugs (or models for drug design) to treat disease. Here, we illustrate the range of immunomodulatory molecules in selected parasitic trematodes, cestodes and nematodes, their impact on the immune cells in the host and how the host may recognize these molecules. There are many examples of the partial characterization of helminth-derived immunomodulatory molecules, but these have not yet translated into new drugs, reflecting the difficulty of isolating and fully characterizing proteins, glycoproteins and lipid-based molecules from small amounts of parasite material. However, this should not deter the investigator, since analytical techniques are now being used to accrue considerable structural information on parasite-derived molecules, even when only minute quantities of tissue are available. With the introduction of methodologies to purify and structurally-characterize molecules from small amounts of tissue and the application of high throughput immunological assays, one would predict that an assessment of parasitic helminths will yield a variety of novel drug candidates in the coming years.

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“…Despite the occurrence of carbohydrates, indicated from lectin binding and biochemical data, a distinct surface coat comparable to that of many cell types was not observed in mature schistosomes (McLaren, 1980) and its demonstration by electron microscopy remained circumstantial (McDiarmid & Podesta, 1984).…”

Section: Membrane and Glycan Preservationmentioning

confidence: 99%

Glycans withN-acetyllactosamine type 2-like residues covering adultSchistosoma mansoni, and glycomimesis as a putative mechanism of immune evasion

Schmidt

1995

Parasitology

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Glycans at the surface of adult Schistosoma mansoni were investigated with gold-labelled lectins. The fragile complex of the glycans with the outer membranes could be preserved for electron microscopy by avoiding extensive pre-fixation with aldehydes and by introducing osmium-ferrocyanide as a membrane fixative. Male and female worms were entirely covered with glycans that intensely bound lectins from Erythrina cristagalli and Datura stramonium, suggesting that galactose(beta 1-4)N-acetylglucosamine residues occur in high numbers in the surface glycans. Similar staining was obtained with lectins from Triticum vulgaris, Glycine max and Ricinus communis agglutinin I, which react with N-acetylglucosamine or terminal galactose residues and bind non-selectively with high affinity to N-acetyllactosamine. Fucose, N-acetylgalactose and sialic acid were not detected with lectins and sialidase treatment. The tegument contained an abundance of glycans with the same lectin reactivities as the surface-expressed molecules, indicating that the worms synthesize and replenish their surface glycans and do not merely adsorb host substances. Glycomimesis is discussed as a mechanism of immune evasion in view of N-acetyllactosamine being a common and weakly immunogenic component in glycans of vertebrate hosts. S. mansoni might disguise themselves with the glycans against attack by immune effectors.

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Identification of a sialic acid containing glycocalyx on the surface of Schistosoma mansoni

Cited by 19 publications

References 37 publications

Opisthorchis viverrini: ultrastructure and cytochemistry of the glycocalyx of the tegument

Opisthorchis viverrini: ultrastructure and cytochemistry of the glycocalyx of the tegument

Parasitic helminths: a pharmacopeia of anti-inflammatory molecules

Glycans withN-acetyllactosamine type 2-like residues covering adultSchistosoma mansoni, and glycomimesis as a putative mechanism of immune evasion

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