Schistosoma mansoni ex vivo lung-stage larvae excretory-secretory antigens as vaccine candidates against schistosomiasis.
ABSTRACT Schistosoma mansoni lung-stage larvae are known to be the major target of innate and acquired immunity to schistosomiasis. Lung schistosomula cytosolic or surface membrane antigens are hidden, entirely inaccessible to the host immune system, and hence are not particularly important as vaccine candidates. Conversely, excretory-secretory (E-S) products released from intact, viable, elongated, and contractile schistosomula are ideal potential vaccines, as such molecules can readily play a central role in the induction of local primary and memory immune response effectors that would directly target, surround, and pursue the larvae while negotiating the lung capillaries. Therefore, 6-day-old ex vivo larvae were isolated from mouse or hamster lung cells and used for generation of E-S products, which were shown to elicit strong immune responses and significant (P<0.05) protection against challenge infection in BALB/c mice. Proteomic analysis of E-S molecules following 10x concentration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis identified peptides related to innumerable host and about 15 S. mansoni-specific proteins. Selected S. mansoni-specific E-S peptides prepared in a multiple antigen peptide (MAP) or recombinant form were shown to stimulate considerable specific antibody response and peripheral blood mononuclear cell expression of mRNA for several cytokines in immunized C57BL/6 and BALB/c mice. However, highly significant (P<0.05 to <0.005) reduction in challenge infection worm burden and egg load was recorded only when the immunization conditions in test mice provided the S. mansoni antigen-specific T helper (Th) type response milieu favorable for each immunogen. That was polarized Th1 for S. mansoni aldolase and thioredoxin peroxidase 1 MAPs, polarized Th2 for recombinant 14-3-3-like protein, mixed Th1/Th17 for calpain MAP, and mixed Th1/Th2 for recombinant p18 protein. The findings together indicated that the immune responses issue is as critical as the nature and source of the antigen for the development of vaccine against schistosomiasis.
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ABSTRACT: Schistosomes are blood trematodes that are perfectly adapted to living in their intravascular habitat and to achieve this they have developed mechanisms enabling them to evade the immune and haemostatic responses of the host and to regulate endothelial cell function to favour their own survival. The objective of this work was to analyse the changes induced by Schistosoma bovis schistosomula in the proteome expressed by infected hamsters, over 10 and 20days, on the endothelial surface of their pulmonary vasculature. To accomplish this, we subjected the lungs of non-infected and S. bovis-infected hamsters to vascular perfusion with a biotin ester reactive. Analysis by liquid chromatography and tandem mass spectrometry analysis (LC-MS/MS) of endothelial surface proteins resulted in the identification of a total of 459 non-redundant proteins in the lung vasculature of infected and non-infected hamsters. Here we report the proteins identified, classified according to their biological function and cellular location, further analysing the differences in lung vascular proteomes between non-infected and S. bovis-infected hamsters for ten and twenty days. This work provides the first data on the vascular surface proteome of the lung after S. bovis infection and identifies some of the changes induced in it during infection. To identify the changes induced by schistosomula larvae of Schistosoma bovis in the proteome of the pulmonary vasculature of the host, we compared the proteins expressed on the vascular endothelium of the lungs of non-infected and infected hamsters over 10 and 20 days. Mass spectrometry analysis (LC-MS/MS) of the proteins isolated from the vascular endothelium resulted in the identification of a total of 459 non-redundant proteins in the lung of infected and non-infected hamsters. The proteins identified are classified according to their biological function and cellular location, further analysing the differences in lung vascular proteomes between non-infected and S. bovis-infected hamsters. This work provides the first data on the vascular surface proteome of the lung after S. bovis infection and identifies some of the changes induced in it during infection suggesting the possible involvement of these proteins during parasite infection.Journal of proteomics 04/2014; DOI:10.1016/j.jprot.2014.04.025 · 5.07 Impact Factor
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ABSTRACT: Each year schistosomiasis afflicts up to 600 million people in 74 tropical and sub-tropical countries, predominantly in the developing world. Yet we depend on a single drug, praziquantel, for its treatment and control. There is no vaccine available but one is urgently needed especially since praziquantel-resistant parasites are likely to emerge at some time in the future. The disease is caused by several worm species of the genus Schistosoma. These express several classes of papain-like cysteine peptidases, cathepsins B and L, in various tissues but particularly in their gastrodermis where they employ them as digestive enzymes. We have shown that sub-cutaneous injection of recombinant and functionally active Schistosoma mansoni cathepsin B1 (SmCB1), or a cathepsin L from a related parasite Fasciola hepatica (FhCL1), elicits highly significant protection (up to 73%) against an experimental challenge worm infection in murine models of schistosomiasis. The immune modulating properties of this subcutaneous injection can boost protection levels (up to 83%) when combined with other S. mansoni vaccine candidates, glyceraldehyde 3-phosphate dehydrogenase (SG3PDH) and peroxiredoxin (PRX-MAP). Here, we discuss these data in the context of the parasite's biology and development, and provide putative mechanism by which the native-like cysteine peptidase induce protective immune responses.Frontiers in Genetics 05/2014; 5:119. DOI:10.3389/fgene.2014.00119This article is viewable in ResearchGate's enriched formatRG Format enables you to read in context with side-by-side figures, citations, and feedback from experts in your field.
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ABSTRACT: In order to explore the high performance bivalent DNA-based vaccine against schistosomes, SjFABP and Sj26GST were selected and used to construct a vaccine. Two strategies were used to construct the bivalent DNA vaccine. In the first strategy, a plasmid encoding antigen in the secreted form was used, while in the other, a plasmid encoding a truncated form of SjFABP and Sj26GST targeted to the cell surface was used. Various parameters, including antibody and cytokine response, proliferation, histopathological examination, and characterization of T cell subsets were used to evaluate the type of immune response and the level of protection against challenge infection. Injection with secreted pIRES-sjFABP-sj26GST significantly increased the levels of antibody, splenocyte proliferation, and production of IFN-γ, compared with membrane-anchored groups. Analysis of splenic T cell subsets showed that the secreted vaccine significantly increased the percentage of CD3(+)CD4(+) and CD3(+)CD8(+) T cells. Liver immunopathology (size of liver granulomas) was significantly reduced in the secreted group compared with the membrane-anchored groups. Moreover, challenge experiments showed that the worm and egg burdens were significantly reduced in animals immunized with recombinant vaccines. Most importantly, secreted Sj26GST-SjFABP markedly enhanced protection, by reducing worm and egg burdens by 31.8% and 24.78%, respectively, while the membrane-anchored group decreased worm and egg burdens by 24.80% and 18.80%, respectively. Taken together, these findings suggest that the secretory vaccine is more promising than the membrane-anchored vaccine, and provides support for the development and application of this vaccine.PLoS ONE 01/2014; 9(1):e86575. DOI:10.1371/journal.pone.0086575 · 3.53 Impact Factor