The Schistosoma mansoni cyclophilin A epitope 107-121 induces a protective immune response against schistosomiasis.

Great efforts have been made to identify promising antigens and vaccine formulations against schistosomiasis. Among the previously described Schistosoma vaccine candidates, cyclophilins comprise an interesting antigen that could be used for vaccine formulations. Cyclophilin A is the target for the cyclosporine A, a drug with schistosomicide activity, and its orthologue from Schistosoma japonicum induces a protective immune response in mice. Although Schistosoma mansoni cyclophilin A also represents a promising target for anti-schistosome vaccines, its potential to induce protection has not been evaluated. In this study, we characterized the cyclophilin A (SmCyp), initially described as Smp17.7, analyzed its allergenic potential using in vitro functional assays, and evaluated its ability to induce protection in mice when administered as an antigen using different vaccine formulations and strategies. Results indicated that SmCyp could be successfully expressed by mammalian cells and bacteria. The recombinant protein did not promote IgE-reporter system activation in vitro, demonstrating its probable safety for use in vaccine formulations. T and B-cell epitopes were predicted in the SmCyp sequence, with two of them located within the active isomerase site. The most immunogenic antigen, SmCyp (107-121), was then used for immunization protocols. Immunization with the SmCyp gene or protein failed to reduce parasite burden but induced an immune response that modulated the granuloma area. In contrast, immunization with the synthetic peptide SmCyp (107-121) significantly reduced worm burden (48-50%) in comparison to control group, but did not regulate liver pathology. Moreover, the protection observed in mice immunized with the synthetic peptide was associated with the significant production of antibodies against the SmCyp (107-121) epitope. Therefore, in this study, we identified an epitope within the SmCyp sequence that induces a protective immune response against the parasite, thus representing a promising antigen that could be used for vaccine formulation against schistosomiasis.

Schistosoma tegument proteins in vaccine and diagnosis development: an update.

The development of a vaccine against schistosomiasis and also the availability of a more sensitive diagnosis test are important tools to help chemotherapy in controlling disease transmission. Bioinformatics tools, together with the access to parasite genome, published recently, should help generate new knowledge on parasite biology and search for new vaccines or therapeutic targets and antigens to be used in the disease diagnosis. Parasite surface proteins, especially those expressed in schistosomula tegument, represent interesting targets to be used in vaccine formulations and in the diagnosis of early infections, since the tegument represents the interface between host and parasite and its molecules are responsible for essential functions to parasite survival. In this paper we will present the advances in the development of vaccines and diagnosis tests achieved with the use of the information from schistosome genome focused on parasite tegument as a source for antigens.

Schistosoma mansoni schistosomula tegument (Smteg) immunization in absence of adjuvant induce IL-10 production by CD4+ cells and failed to protect mice against challenge infection.

The Schistosoma mansoni tegument interaction with the immune system plays a key role in disease establishment or elimination. We have recently demonstrated that S. mansoni schistosomula tegument (Smteg) is able to activate innate immune response and to induce protective immunity in a vaccine formulation with Freunds adjuvant. In this work, we evaluated the ability of Smteg to elicit protection in the absence of adjuvant. Smteg mice immunization resulted in significant antibody production, increased percentage of CD4+IFN-g+ and CD4+IL-10+ cells in spleen and increased production of IFN-g and IL-10 by spleen cells, but failed to reduce parasite burden, female fecundity and morbidity. We also demonstrated that BMDC stimulation with Smteg resulted in significant IL-10 production. Our results demonstrate that Smteg has immune modulatory proprieties.