Vaccination-induced IgG response to Gal alpha 1-3GalNAc glycan epitopes in lambs protected against Haemonchus contortus challenge infection

Lambs vaccinated with Haemonchus contortus excretory/secretory (ES) glycoproteins in combination with the adjuvant Alhydrogel are protected against H. contortus challenge infection. Using glycan micro-array analysis we showed that serum from such vaccinated lambs contains IgG antibodies that recognise the glycan antigen Gal alpha 1-3GalNAc-R and GalNAc beta 1-4(Fuc alpha 1-3)GlcNAc-R. Our studies revealed that H. contortus glycoproteins contain Gal alpha 1-3Gal-R as well as significant levels of Gal alpha 1-3GalNAc-R, which has not been previously reported. Extracts from H. contortus adult worms contain a galactosyltransferase acting on glycan substrates with a terminal GalNAc, indicating that the worms possess the enzymatic potential to synthesise terminal Gal-GalNAc moieties. These data illustrate that glycan micro-arrays constitute a promising technology for fast and specific analysis of serum anti-glycan antibodies in vaccination studies. In addition, this approach facilitates the discovery of novel, antigenic parasite glycan antigens that may have potential for developing glycoconjugate vaccines or utilization in diagnostics. (C) 2009 Australian Society for Parasitology Inc. All rights reserved.