Schistosome N-glycans containing core α3-fucose and core β2-xylose epitopes are strong inducers of Th2 responses in mice

During murine schistosomiasis, egg-derived glycoconjugates; play a key role in skewing the immune response towards a Th2 phenotype. Among the candidates responsible for this effect, complex-type N-glycans containing the core alpha3-fucose and core beta2-xylose determinants, two glycan epitopes found in some invertebrate- and plant-derived allergens, may be important. Here, we show that core alpha3-fucose and core beta2-xylose determinants are expressed in the different developmental stages of Schistosoma mansoni, particularly in the excretory-secretory systems of schistosomula and adult worms and in eggs deposited in the liver. Glycosyltransferase assays confirmed the presence of core alpha3-fucosyltransferase and core beta2-xylosyltransferase activities in egg extracts. Using a model of immunization with pulsed dendritic cells, we show that egg-derived glycoproteins containing the core alpha3-fucose and core beta2-xylose determinants generate a strong Th2-biased cellular response in mice and that the glycan moieties of this extract are important in this effect. During murine infection, these complex-type N-glycans induce a glycan-specific Th2 cellular response and elicit T-dependent anti-core alpha3-fucose and anti-core beta2-xylose IgG1 (a Th2-associated isotype), but not IgG2b (a Th1-associated isotype) Ab. Taken together, our results point out the importance of core fucosylated/xylosylated N-glycans in the Th2 immune response during murine schistosomiasis.