A structure-based approach for novel immunodiagnostics targeting Trypanosoma cruzi and Schistosoma spp.

The tropical diseases Chagas Disease and Schistosomiasis, caused by the parasites Trypanosoma cruzi and Schistosoma spp, respectively, are often misdiagnosed and if untreated can be fatal. Indeed, their diagnosis presents a current challenge, due to difficulties in recognizing clinical symptoms and the lack of specific and reliable diagnostic tools. Highest prevalence is respectively in Latin America and Central Africa. However, massive human migration from endemic areas and travelling to tropical regions, contribute to the diffusion of these diseases in non-endemic areas, increasing the need of rapid diagnostic tools and prevention strategies. The aim of this project is to develop rapid, peptide-based microarrays that present multiple immunoreactive epitopes predicted from 3D protein structures of antigens from several pathogens, to be applied in point-of-care diagnostic kits for use in the Lombardy area of Italy. This approach showed promising results when applied to antigens from bacterial pathogens, in particular Burkholderia pseudomallei that led to the identification of epitopes with both diagnostic and therapeutic potential. Putative antigens selected from both parasites will be overexpressed, purified and crystallized for 3D structure studies. Based on the determined 3D protein structures, Molecular Dynamics (MD) analyses will be carried out and epitope predictions will be made on output MD structures using the Matrix of Local Coupling Energies method that detects residues located in conformationally dynamic regions of the protein surface. Predicted reactive epitopes will be synthetized as peptides, tested for immunoreactivity against immune sera from infected patients and used for antibody production. Selected immunoreactive synthetic peptides will be immobilised in specific orientations, using click chemistry, on a polymeric coated microarray chip. Sensitivity and specificity of the chip will be evaluated with sera of infected patients.