A Native 51 kDa Leishmania Membrane Protein Revealed as a Novel Antigenic Candidate for Immuno-Diagnosis of Human VL and PKDL diseases

Abstract

Background: Visceral leishmaniasis (VL), a potentially devastating neglected tropical disease is a major health concern. Despite recent advances made in diagnosis of VL, an accurate and a reliable diagnostic biomarker is still needed. Objective: This study primarily aims to characterize the 51 kDa protein of Leishmania donovani promastigote membrane antigens (LAg) for diagnosis of VL and post kala-azar dermal leishmaniasis (PKDL). Methods: One of the antigenic components of LAg of molecular weight 51 kDa which was previously identified as elongation factor1-α (EF1-α), was electroeluted and confirmed with anti-EF1-α antibody through immunoblot assay. Sero-diagnostic potential of 51 kDa antigen and one of its B cell epitopes was accessed through ELISA. The 51 kDa was further elucidated for urine-based diagnosis of PKDL. Results: In the present study 51 kDa antigen was investigated for reactivity with VL patients’ sera. A strong immuno-reactivity of this antigen was observed in ELISA demonstrating 98.27% sensitivity with VL sera and 93.33% specificity with endemic and nonendemic healthy controls as well as other diseases. Further a B cell epitope of 51 kDa antigen was found to be 100% sensitive and 93.33% specific in ELISA. Additionally, in another ELISA 51 kDa antigen showed 100% sensitivity and specificity with PKDL patients’ urine. Conclusion: The data obtained from this study leverage the potential of 51 kDa antigen in diagnosis of VL and PKDL which can be developed as a rapid diagnostic test.