A proteomic approach to the identification of tegumental proteins of male and female Schistosoma bovis worms

Abstract

Schistosoma bovis, a parasite of ruminants, can live for years in the bloodstream in spite of the immune response of its host. The parasite tegument covers the entire surface of theworm and plays a key role in the host–parasite relationship. The parasite molecules involvedin hostimmuneresponse evasionmechanisms must be expressed on the tegument surface and are potential targets for immune or drug intervention. The purpose of the presentworkwas to identify the tegumental proteomes of male and female S. bovisworms, in particular the proteins expressed on the outermost layers of the tegument structure. Adult worms of each sexwere treated separately with trypsin in order to digest their tegumental proteins, after which the peptides released were analysed by LC–MS/MS for identification. This experimental approach afforded valuable information about the protein composition of the tegument of adult S. bovis worms. A range of tegumental proteins was identified, most of which had not been identified previously in this species. Although an absolute purification of the proteins expressed on the outermost layers of the tegument structurewas not achieved, it is likely that present among the proteins identified are some of the molecules most closely associated with the tegument surface. Our study also suggests that theremay be differences in the protein composition of the tegument of male and female schistosomes. Finally, the presence of actin and GAPDH on the surface of male and female worms and the presence of enolase exclusively on the surface of male worms were verified by confocal microscopy.