Project Summary
More than 1 billion people are at risk worldwide for developing schistosomiasis caused by one of
five species of Schistosoma. Two species that cause the most human disease, Schistosoma
japonicum and Schistosoma mansoni, infect the intestine and liver by similar processes, but differ
in their geographically distribution. Neither are thought to be contained, and both have increased
their global footprint to new regions of the world. In addition to infecting humans, S. japonicum
infects cattle and water buffalo, which are greatly needed for meat, milk, as well as for farming.
Infection of livestock results in significant financial losses to farmers and is also considered to be
a key factor in human transmission. There currently is no vaccine for S. japonicum in animals or
humans, and very few prospective vaccines are under consideration. The only cure for
schistosomiasis is an anti-parasitic drug, praziquantel, and there is inherent fear that these
parasites will eventually develop drug resistance. We are proposing to develop a vaccine for S.
japonicum based on a similar vaccine we have developed for S. mansoni called SchistoShield®.
SchistoShield®, which is based on a single parasitic protein called Sm-p80, is the only vaccine
currently under evaluation that impacts nearly all phases of the Schistosoma life cycle. We have
recently isolated the identical protein in S. japonicum, called Sj-p80, that it is nearly identical to
Sm-p80. Because Sm-p80 provides partial protection against S. japonicum infection in mice, we
predict that Sj-p80 will provide superior protection against this disease. The goals of this proposal
are: 1) produce Sj-p80 protein for immunization of mice; 2) demonstrate in mice that Sj-p80 protein
exhibits superior protection against S. japonicum compared to Sm-p80, and 3) develop a low cost,
minimally purified version of the Sj-p80 that would be a suitable veterinary vaccine while still
providing complete protection. Successful completion of this grant will validate Sj-p80 as a viable
veterinary vaccine against Asiatic schistosomiasis. If the antigen holds promise in protection
against Asian schistosomiasis, the proposed activities will allow us to move towards testing in
cattle and commercialization of the veterinary vaccine in endemic countries as well as towards
future human clinical trials.