Recognition of Highly Branched N-Glycans of the Porcine Whipworm by the Immune System

Glycans are key to host–pathogen interactions, whereby recognition by the host and immunomodulation by the pathogen can be mediated by carbohydrate binding proteins, such as lectins of the innate immune system, and their glycoconjugate ligands. Previous studies have shown that excretory-secretory products of the porcine nematode parasite Trichuris suis exert immunomodulatory effects in a glycan-dependent manner. To better understand the mechanisms of these interactions, we prepared N-glycans from T. suis and both analyzed their structures and used them to generate a natural glycan microarray. With this array, we explored the interactions of glycans with C-type lectins, C-reactive protein, and sera from T. suis–infected pigs. Glycans containing LacdiNAc and phosphorylcholine-modified glycans were associated with the highest binding by most of these proteins. In-depth analysis revealed not only fucosylated LacdiNAc motifs with and without phosphorylcholine moieties but phosphorylcholine-modified mannose and N-acetylhexosamine–substituted fucose residues, in the context of maximally tetraantennary N-glycan scaffolds. Furthermore, O-glycans also contained fucosylated motifs. In summary, the glycans of T. suis are recognized by both the innate and adaptive immune systems and also exhibit species-specific features distinguishing its glycome from those of other nematodes. [Display omitted] •The porcine whipworm, Trichuris suis, has a complex and unique N-glycome.•MS/MS reveals many LacdiNAc motifs substituted with fucose and phosphorylcholine.•Glycan array data show recognition by immune lectins and infection sera. Glycan-dependent host immunomodulation has been previously reported in the case of the porcine parasite Trichuris suis. Using off-line HPLC/MALDI-TOF-MS/MS, we reveal a high degree of N-glycomic variety with LacdiNAc-type antennae modified with fucose and/or phosphorylcholine residues as well as HexNAc-substituted fucose. A natural glycan array was also generated whose application showed that selected fractions of HPLC-separated N-glycans were recognized by mammalian innate immune lectins and antibodies in the sera of infected pigs.