Evaluation of the use of C-terminal part of the Schistosoma mansoni 200kDa tegumental protein in schistosomiasis diagnosis and vaccine formulation.

Schistosoma mansoni tegument is involved in essential functions for parasite survival and represents a target for screening candidates for vaccine and diagnosis. Our group using reverse vaccinology selected six candidates, previously demonstrated by proteomics studies to be expressed in the parasite tegument, among them was Sm200. In this work we have cloned and expressed a recombinant form of Sm200 C-terminal (1069-1520) region. The efficacy of rSm200 (1069-1520) in the diagnosis of schistosomiasis and in the formulation of a vaccine against S. mansoni was assessed respectively in an ELISA based diagnostic assay and immunization protocols in mice. Significant differences between non-infected and acutely infected or chronically infected animals were observed and no cross-recognition was observed with sera from Ascaris suum or Ancylostoma ceylanicum infected mice. rSm200-ELISA test could also discriminate infected individuals from healthy donors not living in endemic area for schistosomiasis but failed to discriminate between individuals from a low endemic area for schistosomiasis known to have positive or negative stools after examination. Recombinant Sm200 also failed to induce protection against schistosomiasis, demonstrating that the C-terminal part of Sm200 is unable to induce protective immune response in mice. Therefore rSm200 (1069-1520)-ELISA represents an important tool to be used in the diagnosis of schistosomiasis.