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Fatty acid binding proteins (FABP) from Fasciola hepatica have demonstrated immune cross-protection against schistosomes. The present study was conducted to develop a new formulation of the recombinant FABP rFh15 with the synthetic immunomodulator AA0029 in the adjuvant adaptation (ADAD) vaccination system and to evaluate its ability to induce immune response and protection against the challenge with Schistosoma bovis cercariae. Immunization of BALB/c mice showed high levels of TNFα, IFNγ, interleukin (IL)-2, IL-6, and IL-4 in splenocyte supernatant culture and also high levels of serum specific anti-rFh15 IgG, IgG1, IgG2a IgE and IgM antibodies suggesting a mixed Th1/Th2 immune response. Using this approach, high levels of protection against experimental challenge with S. bovis cercariae were observed in the mouse and hamster models. A marked reduction up to 64% in worm burden, as well as in the number of eggs retained in liver (66%) and intestine (77%) and hepatic lesions (42%), was achieved in vaccinated BALB/c mice. Golden hamsters vaccinated and challenged in similar conditions had reductions in recovered worms (83%), liver eggs (90%), intestine eggs (96%), liver lesions (56%) and worm fecundity (48-80%). These data suggest that formulation of rFh15 in the ADAD vaccination system using the AA0029 immunomodulator could be a good option to drive an effective immunological response against schistosomiasis., (Copyright © 2015 Elsevier Inc. All rights reserved.)

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 the worm and plays a key role in the host-parasite relationship. The parasite molecules involved in host immune response evasion mechanisms must be expressed on the tegument surface and are potential targets for immune or drug intervention. The purpose of the present work was to identify the tegumental proteomes of male and female S. bovis worms, in particular the proteins expressed on the outermost layers of the tegument structure. Adult worms of each sex were 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 structure was 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 there may 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.

Schistosoma bovis is a parasite of wild and domestic ruminants that is broadly distributed throughout many tropical and temperate regions of the old world. S. bovis causes severe health problems and significant economic losses in livestock, but in contrast to human schistosomes, S. bovis has been little investigated at a molecular level. Since schistosome glycans and glycoproteins can play important roles in the host-parasite interplay, the aims of the present work were: (i) to characterize the glycans expressed by adult S. bovis worms on their excreted/secreted (ES) and tegumental (TG) glycoproteins and (ii) to identify their carrier protein backbones by mass spectrometry. Using a panel of lectins and monoclonal and polyclonal anti-glycan antibodies, we observed: (i) the absence of sialic acid in S. bovis; (ii) the presence of complex-type N-glycans and LDN antennae on ES glycoproteins; (iii) the presence of glycans containing the Fucalpha1-2Galbeta motif in many TG glycoproteins, and (iv) the presence of glycans containing the Fucalpha1-3GlcNAc motif on many ES and TG glycoproteins but, simultaneously, the absence of the F-LDN(-F) glycans from both the ES and TG glycoproteins. Interestingly, we also found the Lewis(X) and Lewis(Y) antigens co-expressed on several TG isoforms of ATP:guanidino kinase and glyceraldehyde-3-phosphate dehydrogenase. Finally, by ELISA we observed the presence of antibodies against Lewis(X), Lewis(Y) and F-LDN(-F) in the sera of sheep experimentally infected with S. bovis.

Schistosoma bovis is a ruminant haematic parasite that lives for years in the mesenteric vessels of the host. The aim of this work was to investigate the ability of adult S. bovis worms to interact with plasminogen, a central component in the host fibrinolytic system. Confocal microscopy analysis revealed that plasminogen bound to the tegument surface of the male-but not female-S. bovis worms and that this binding was strongly dependent on lysine residues. It was also observed that a protein extract of the worm tegument (TG) had the capacity to generate plasmin and to enhance the plasmin generation by the tissue-type plasminogen activator. Proteomic analysis of the TG extract identified 10 plasminogen-binding proteins, among which the major ones were enolase, glyceraldehyde-3-phosphate dehydrogenase and actin. This study represents the first report about the binding of plasminogen to Schistosoma sp. proteins.

Schistosoma bovis is a ruminant pathogen that is poorly known at a molecular level. With an aim of identifying the parasite proteins involved in host-parasite interplay, we studied two protein extracts that contain, respectively, the proteins excreted/secreted by the adult worm (ES) and the tegumental proteins exposed to the host (TG). The 2-DE, 2-D immunoblot and MS were employed to separate and identify the antigenic proteins and the most abundant non-antigenic proteins in each extract. There were some 400 and 600 spots detected in the ES and the TG extracts, respectively. Ninety-six spots were subjected to MS analysis and 64 of them were identified. Overall, we identified 18 S. bovis proteins located at the host-parasite interface, 16 of which have not been identified previously in this parasite, and one of which -lysozyme- has never been reported in a Schistosoma species. Of the proteins identified, at least 4 can counteract host defence mechanisms. The other proteins are also likely to play some role in the host-parasite relationships. Therefore, studies in grater depth on all these proteins will provide a better understanding of how this parasite interacts with its host and new strategies for anti-schistosome drug or vaccine design.

Sheep infected with Fasciola hepatica for 10 wk acquired a substantial level of resistance to challenge with Schistosoma bovis. The worm burden was reduced by 87.2% (P < 0.01) compared with that of a control group. But when sheep primarily were infected with S. bovis and 6 wk later with F. hepatica, no significant reduction in the S. bovis burden was observed.