Schistosomiasis remains a major global health problem. Despite large-scale
schistosomiasis control efforts, clear limitations such as possible emergence of drug resistance and
reinfection rates highlight the need for an effective
schistosomiasis vaccine. Schistosoma mansoni large subunit of
calpain (Sm-p80)-based
vaccine formulations have shown remarkable efficacy in protecting against S. mansoni challenge
infections in mice and baboons. In this study, we evaluated the cross-species protective efficacy of Sm-p80
vaccine against S. japonicum and S. haematobium challenge
infections in rodent models. We also elucidated the expression of Sm-p80 and Sm-p80 ortholog
proteins in different developmental stages of S. mansoni, S. haematobium, and S. japonicum. Immunization with Sm-p80
vaccine reduced worm burden by 46.75% against S. japonicum challenge
infection in mice.
DNA prime/
protein boost (1 + 1 dose administered on a single day) resulted in 26.95% reduction in worm burden in S. haematobium-hamster
infection/challenge model. A balanced Th1 (IFN-γ, TNF-α, IL-2, and IL-12) and Th2 (IL-4, IgG1) type of responses were observed following vaccination in both S. japonicum and S. haematobium challenge trials and these are associated with the prophylactic efficacy of Sm-p80
vaccine. Immunohistochemistry demonstrated that Sm-p80/Sm-p80 ortholog
proteins are expressed in different life cycle stages of the three major human species of schistosomes studied. The data presented in this study reinforce the potential of Sm-p80-based
vaccine for both hepatic/intestinal and
urogenital schistosomiasis occurring in different geographical areas of the world. Differential expression of Sm-p80/Sm-p80
protein orthologs in different life cycle makes this
vaccine potentially useful in targeting different levels of
infection, disease, and transmission.