Expression, purification and evaluation of arginine kinase from infective larvae of Strongyloides stercoralis and S. venezuelensis as biomarkers for the serodiagnosis of human strongyloidiasis

• Grant number: 23/07417-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Effective date (Start): October 01, 2023
• Effective date (End): September 30, 2025
• Field of knowledge: Biological Sciences - Pharmacology - Biochemical and Molecular Pharmacology
• Principal Investigator: Gisele Monteiro
• Grantee: William Henry Roldán Gonzáles
• Host Institution: Faculdade de Ciências Farmacêuticas (FCF). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Human strongyloidiasis, caused by the nematode Strongyloides stercoralis, is a neglected tropical disease with more than 600 million people infected worldwide. Traditional diagnosis of strongyloidiasis, based on the detection of parasite larvae in feces, is inefficient due to its low sensitivity requiring several fecal samples to confirm the clinical suspicion. On the other hand, detection of antibodies against Strongyloides antigens using the ELISA test is more sensitive and practical, and can be used both in clinical diagnosis and in seroepidemiological surveys. However, its main disadvantage is the cross-reactivity with other types of helminths, especially in endemic regions of helminthiases, due to the use of somatic extracts of the parasite. Recent studies of our group have observed that the secreted products by S. venezuelensis infective larvae (a Strongyloides species that infects rodents and is used as study model) contain antigenic proteins including a 37-kDa arginine kinase (Sv-AK37), identified by immunoproteomic analysis, with a sensitivity and specificity of 93 and 100%, respectively. A bioinformatic analysis showed that Sv-AK37 contains several antigenic regions in common with its homologue present in S. stercoralis. The possibility of using recombinant DNA technology for the expression and production of these antigenic proteins could open new horizons in the biology of the host-parasite relationship, but also in the improvement of the serodiagnosis for human strongyloidiasis. Therefore, the main objective of this research project will be to express, purify and evaluate the arginine kinase from S. venezuelensis and S. stercoralis as potential biomarkers for the serodiagnosis of human strongyloidiasis by ELISA test, to evaluate "in vitro" its function as activator of innate immune response in macrophages, and evaluate its potential as possible vaccine candidate. (AU)