Structure, Immunoreactivity, and In Silico Epitope Determination of SmSPI S. mansoni Serpin for Immunodiagnostic Application

• Published in: Vaccines (Basel) Vol. 9; no. 4; p. 322
• Main Authors: De Benedetti, Stefano, Di Pisa, Flavio, Fassi, Enrico Mario Alessandro, Cretich, Marina, Musicò, Angelo, Frigerio, Roberto, Mussida, Alessandro, Bombaci, Mauro, Grifantini, Renata, Colombo, Giorgio, Bolognesi, Martino, Grande, Romualdo, Zanchetta, Nadia, Gismondo, Maria Rita, Mileto, Davide, Mancon, Alessandro, Gourlay, Louise Jane
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.04.2021; MDPI
• Subjects: Antibodies; Antigens; Biomarkers; Chromatography; circulating antigen; Crystal structure; Crystallization; Drug resistance; Epitope mapping; Fresh water; Immigration; Immune serum; Immunoreactivity; in silico epitope predictions; Infections; Neglected Tropical Disease; Parasites; Parasitic diseases; Pathogens; Protease inhibitors; Proteinase inhibitors; Proteins; Schistosoma; Schistosoma mansoni; Schistosomiasis; Serine; Serine protease inhibitor; Serine proteinase; Tropical diseases; Tropical environment; Tropical environments; United States > US; in silico epitope predictions; Neglected Tropical Disease; crystal structure; circulating antigen; immunodiagnostics; schistosomiasis; Serine protease inhibitor
• ISSN: 2076-393X; 2076-393X
• DOI: 10.3390/vaccines9040322

The human parasitic disease Schistosomiasis is caused by the trematode flatworm that infects freshwaters in tropical regions of the world, particularly in Sub-Saharan Africa, South America, and the Far-East. It has also been observed as an emerging disease in Europe, due to increased immigration. In addition to improved therapeutic strategies, it is imperative to develop novel, rapid, and sensitive diagnostic tests that can detect the parasite, allowing timely treatment. Present diagnosis is difficult and involves microscopy-based detection of Schistosoma eggs in the feces. In this context, we present the 3.22 Å resolution crystal structure of the circulating antigen Serine protease inhibitor from (SmSPI), and we describe it as a potential serodiagnostic marker. Moreover, we identify three potential immunoreactive epitopes using in silico-based epitope mapping methods. Here, we confirm effective immune sera reactivity of the recombinant antigen, suggesting the further investigation of the protein and/or its predicted epitopes as serodiagnostic Schistosomiasis biomarkers.