Coordination of humoral immune factors dictates compatibility betweenSchistosoma mansoniandBiomphalaria glabrata

Abstract

AbstractImmune factors in snails of the genusBiomphalariaare critical for combatingSchistosoma mansoni, the predominant cause of human intestinal schistosomiasis. Independently, many of these factors are known to play an important role in, but not fully define, the compatibility between the model snailB. glabrata,andS. mansoni. Here, we demonstrate association between four, previously characterized humoral immune molecules;BgFREP3,BgTEP1,BgFREP2 and Biomphalysin. We also identify unique immune determinants in the plasma ofS. mansoni-resistantB. glabratathat explain the incompatible phenotype. These factors coordinate to initiate haemocyte-mediated deestruction ofS. mansonisporocysts via production of reactive oxygen species. The inclusion ofBgFREP2 in aBgFREP3-initiated complex that also includesBgTEP1 almost completely explains resistance toS. mansoniin this model. Our study unifies many independent lines of investigation to provide a more comprehensive understanding of the snail immune system in the context of infection by this important human parasite.