Discussion

Helminths express an abundance of proteins and lipids with complex glycosylation patterns. Glycomics studies are providing more and more insights into glycan and glycoconjugate expression by different helminth species, including major trematodes, nematodes and cestodes of clinical and veterinary importance such as Schistosoma, H. contortus, F. hepatica and Echinococcus. Antigenic glycans of different life stages of most helminths induce specific antibodies in the mammalian host, and helminth-associated glycan motifs trigger innate mechanisms that modulate inflammatory immune responses.

In particular schistosomes have been extensively studied with respect to structural and functional glycomics. To provide a map of schistosome glycosylation in support of functional studies of host-parasite glycobiology my research group  applied mass spectrometric (MS) glycomics approaches to determine expression profiles of hundreds of protein- and lipid-linked glycans during the schistosome life cycle. In addition, we have generated a microarray of hundreds of N-, O-, and lipid-glycans covering the entire glycome of S. mansoni. The constructed glycan microarray was used to determine IgG and IgM to each glycan in human and animal infection cohorts.

Striking shifts and switches in the expression of putative functional glycan motifs during during worm and egg development were identified suggesting various roles of glycans and associated anti-glycan responses during infection. For instance, using clear examples, I will discuss how glycan motifs contribute to characteristic immunomodulatory properties of schistosome egg antigens such as omega-1. Also, based on cross-sectional and longitudinal studies of antibodies in sera from natural and experimental schistosome infections, I will discuss the potential of antibodies against specific glycan motifs as targets for schistosomiasis vaccines and diagnostics. The schistosome glycomics data will be discussed in relation to the glycome and glycogenome of other helminth species. It is concluded that schistosome glycans are attractive targets for novel therapeutics and control tools.