A library of cell-surface and secreted proteins from Schistosoma mansoni identifies early serological markers of infection

Abstract

Schistosomiasis is a major global health problem caused by blood-dwelling parasitic worms and is currently treated by the mass administration of the drug praziquantel. Appropriate drug treatment strategies are informed by diagnostics that establish the prevalence and intensity of infection, which, in regions of low transmission should be highly sensitive. To identify sensitive new serological markers of Schistosoma mansoni infections, we have compiled a recombinant protein library of 115 parasite cell surface and secreted proteins expressed in mammalian cells. The vast majority of them were shown to be immunoreactive and to contain heat-labile conformational epitopes when tested against pooled human sera from endemic regions. After probing the library against a time series of sera samples from experimental infections in mice, we identified several markers of infection, the majority of which belong to the saposin-domain-containing and cathepsin families of proteins. These new markers will be a valuable tool to detect ongoing and previous S. mansoni infections, including in regions of low transmission. We envisage that this new recombinant protein resource will be used in a wide range of cellular and molecular assays to further our understanding of Schistosoma biology.