# Site- and structure-specific characterization of glycoproteins of H11: potent vaccine candidates against parasitic worm Haemonchus

## TL;DR

This study identifies glycoproteins in a parasitic worm antigen that could serve as vaccine candidates by analyzing their structure and function.

## Contribution

The study provides a site- and structure-specific glycoproteomic analysis of the H11 antigen from Haemonchus contortus.

## Key findings

- Seven glycosylated aminopeptidases with 19 N-glycosylation sites and 31 distinct N-glycan structures were identified.
- 13 N-glycopeptides were significantly enriched by H11-induced protective IgG antibodies.
- IgG-recognized N-glycopeptides were located on the protein surface or near substrate-access channels.

## Abstract

Parasitic worm (helminth) infections pose significant threats to global health and livestock productivity. Although mass spectrometry (MS)-based glycomics have revealed that helminths express structurally complex N-glycans, site- and structure-specific characterization of intact glycopeptides remains a major challenge. Here we employed advanced MS-based intact glycoproteomics to explore the N-glycosylation profile of H11 antigen – an important vaccine antigen derived from the pathogenic parasite Haemonchus contortus. We identified seven glycosylated aminopeptidases carrying 19 N-glycosylation sites with 31 distinct N-glycan structures. Notably, 13 N-glycopeptides were significantly enriched by H11-induced protective IgG antibodies. Our results revealed extensive structural heterogeneity and abundant core fucosylation among the identified N-glycopeptides. Additionally, molecular docking analyses demonstrated that these IgG-recognized N-glycopeptides were located on the protein surface or near substrate-access channels, indicating their potential as antigenic epitopes. Overall, this work provides a precise glycoproteomic characterization of a key helminth antigen and offers valuable insights for the rational design of vaccines against H. contortus and other related parasitic species.