Sm60, a mannose-binding protein from Schistosoma mansoni with inflammatory property

We demonstrate here that a mannose-binding protein from Schistosoma mansoni, termed Sm60, was recovered in the mannose-eluted fraction (Man(+)) upon affinity chromatography on immobilised mannose of the soluble antigen fraction from adult worm tegument and cercariae. Sm60 was detected in the Man(+) fraction as a prominent doublet with an apparent molecular mass of 60-66 kDa by SDS-PAGE and appeared as a single band with a pI of approximately 6.9 by isoelectrofocusing. Sm60 was also detected in preparations of schistosomula extract and soluble egg antigens using a mouse polyclonal anti-Sm60 serum on immunoblotting assay. This antiserum demonstrated that Sm60 was localised on the tegument of S. mansoni adult worm. In order to determine the role of Sm60 in host-parasite interactions, we showed that Sm60 induced in vitro migration of human neutrophil in a dose-dependent manner and in vitro mast cell degranulation. Sm60 triggered these activities through its carbohydrate-binding site, since these activities were selectively inhibited by 0.2 M D-mannose, but not by 0.2 M D-galactose. Furthermore, Sm60 induced in vivo neutrophil migration. In contrast, mast cell-depleted rats presented a significant reduction of the neutrophil migration induced by Sm60 as compared with non-depleted controls. These data suggest that in vivo neutrophil migration induced by Sm60 is modulated by mast cell-dependent mechanisms. Sm60 might play a key role in the host-parasite interaction, and its characterization opens perspective to examine the role of this molecule in the biology of S. mansoni.