r-Sm14 - pRSETA efficacy in experimental animals

Abstract

Previous studies carried out with Sm14 in experimental vaccination against Schistosoma mansoni or Fasciola hepatica infections were performed with recombinant Sm14 (rSm14) produced in Escherichia coli by the pGEMEX system (Promega). The rSm14 was expressed as a 40 kDa fusion protein with the major bacteriophage T7 capsid protein. Vaccination experiments with this rSm14 in animal models resulted in consistent high protective activity against S. mansoni cercariae challenge and enabled rSm14 to be included among the vaccine antigens endorsed by the World Health Organization for phase I/II clinical trials. Since the preparation of pGEMEX based rSm14 is time consuming and results in low yield for large scale production, we have tested other E. coli expression systems which would be more suitable for scale up and downstream processing. We expressed two different 6XHis-tagged Sm14 fusion proteins in a T7 promoter based plasmids. The 6XHis-tag fusions allowed rapid purification of the recombinant proteins through a Ni+2-charged resin. The resulted recombinant 18 and 16 kDa proteins were recognized by anti-Sm14 antibodies and also by antiserum against adult S. mansoni soluble secreted/excreted proteins in Western-Blot. Both proteins were also protective against S. mansoni cercariae infection to the same extent as the rSm14 expressed by the pGEMEX system

RecombinantMycobacterium bovisBCG Expressing the Sm14 Antigen ofSchistosoma mansoniProtects Mice from Cercarial Challenge

“…In previous studies (26,30), the rSm14 vaccine induced protection levels of up to 65% in outbred mice who received three doses of 10 g each, and a level of 89% protection was recorded for rabbits immunized with three doses of 80 g each (30). These results were highly encouraging, but it would be desirable to have a standardized recombinant vaccine which could achieve similar levels of protection when given as a single dose.…”

“…This antigen, when produced as a recombinant protein by Escherichia coli, has been shown to form the basis for a dual-purpose antihelminth vaccine that is capable of conferring protection in outbred mice and rabbits against infection by S. mansoni and the ruminant helminth Fasciola hepatica (26,30). The latter parasite is the causative agent of fascioliasis, an economically important disease of cattle and sheep in Europe, the Americas, and Australasia (12).…”

Losac, the First Hemolin that Exhibits Procogulant Activity through Selective Factor X Proteolytic Activation

“…The PCR product and the pAE vector (27) were restricted with NcoI and EcoRI, purified, and ligated with T4 DNA ligase. The sequences of the insert and frame were confirmed by DNA sequencing.…”

Sm14 of Schistosoma mansoni in Fusion with Tetanus Toxin Fragment C Induces Immunoprotection against Tetanus and Schistosomiasis in Mice

“…The choice of Sm14 was motivated by the global importance of schistosomiasis (2,4,22) and by the fact that the protein itself is one of the few vaccine candidates that consistently induces 50% protection against S. mansoni cercariae in experimental animal models (16,17,20,23). In addition, Sm14 affords 100% protection against F. hepatica, a recognized agricultural problem (23).…”

“…Schistosoma mansoni fatty acid-binding protein 14 (Sm14) and the 28-kDa glutathione S-transferase from Schistosoma haematobium (Sh28-GST) are now considered by the World Health Organization to be the target molecules for an antischistosome vaccine (2,3,4).The recombinant protein showed a protective activity against two parasitic worm species, S. mansoni and Fasciola hepatica, inducing a 35 to 60% reduction in the number of adult S. mansoni worms and a 100% reduction in the F. hepatica worm burden (16,17,20,23).…”