Table 1.
Current schistosomiasis vaccine candidates
| Schistosoma species | Developer | Vaccine | Target antigen proposed mechanism of action | Status | Outcomes |
|---|---|---|---|---|---|
| S. haematobium | INSERM and Eurogentec | Monovalent recombinant protein with alum (Bilhvax) | Sh28 GST glutathione S-transferase | Phase I and II studies completed (phase Ia in Europe on adults, phase Ib in Senegal on children); currently in phase III trial (result due in 2013) | Safe and immunogenic, induced IgG1, IgG2, IgG3 isotypes, and antisera reduced GST28 enzymatic activities; induced Th2 type cytokine responses |
| S. mansoni | FIOCRUZ | Monovalent recombinant protein in glucopyranosyl lipid adjuvant–stable emulsion | Fatty acid binding protein- Sm14 | Phase I trial completed | Well tolerated and safe |
| S. mansoni | Sabin Vaccine Institute | Monovalent Recombinant protein with adjuvant | Tetraspanin surface antigen; Sm-TSP-2 to affect parasite membrane biogenesis in schistosomules and adult worms | Preclinical process development completed, good laboratory practice toxicity study and current good manufacturing practices completed. Phase I slated for late 2013 | Adult worm and egg burden reduction by 40–60% (mice); human IgG antibody associated with putative resistance |
| S. japonicum, S. mansoni | University of Georgia | DNA prime, recombinant protein boost | Target antigens tetraspanin (SmSj23) and glycolytic enzyme TPI (SmSjTPI): interfere with invading larva survival, leading to reduced adult worms in livestock and humans (vaccine for humans or for animals to reduce transmission to humans) | Field studies in water buffalo and cattle with SjTPI | Reduction in adult worm burden by ≈55% and egg burden by ≈57% in experimental challenge studies (with Sj23 and SjTPI) ; (field studies with an improved new delivery method for SjTPI ongoing in China and the Philippines) |
| S. mansoni | Texas Tech University Health Sciences Center | Monovalent recombinant protein with adjuvant | Sm-p80 calpain protein to affect parasite surface membrane renewal of tegument of lung-stage schistosomula (prophylactic) or epithelial syncytium of the adult parasite (therapeutic) | Animal proof-of-concept studies completed; process development ongoing | Worm reduction in prophylactic model: 70% (mice), 60% (baboons); egg reduction in prophylactic model: 100% (mice), 100% (baboons); showed complete elimination of egg-induced organ pathology |
| S. japonicum | Brown University | Monovalanet recombinant protein with adjuvant | Paramyosin 97-kD protein Sj97 expressed on schistosomular surface, tegument and acetabular glands, binds complement and Fc region of IgG; proposed role in host immune evasion | Currently early preclinical process development and proof-of-concept studies in mice and buffalo | Worm reduction by 52% in mice and 50% in buffalo |
| S. japonicum | Queensland Institute of Medical Research | Bivalent (SjIR and SjTPI) recombinant proteins with adjuvant | Insulin receptor SjIR targets to host insulin binding and prevent worm glucose uptake and SjTPI inhibits worm glycolysis | Currently testing in mice, planned in buffalo in China and the Philippines | Adjuvanted monovalent SjIR reduced fecal eggs in mice by 56–67%; SjTPI reduced worms by 48–52% in buffalo |