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BioMed Research International
Volume 2017 (2017), Article ID 2145386, 14 pages
https://doi.org/10.1155/2017/2145386
Research Article

Immune Response and Protective Efficacy of a Heterologous DNA-Protein Immunization with Leishmania Superoxide Dismutase B1

1Department of Biological Sciences, University of Calgary, Room 374, 2500 University Drive NW, Calgary, AB, Canada T2N 1N4
2Department of Medical Parasitology, School of Biomedical and Laboratory Sciences, College of Medicine and Health Sciences, University of Gondar, P.O. Box 196, Gondar, Ethiopia
3The Forsyth Institute, Cambridge, MA 02142, USA

Correspondence should be addressed to Abebe Genetu Bayih; moc.liamg@utenegebeba

Received 26 May 2017; Accepted 19 October 2017; Published 22 November 2017

Academic Editor: Carmen Thomas

Copyright © 2017 Abebe Genetu Bayih et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Growing evidence shows that antioxidant proteins of Leishmania could be used as vaccine candidates. In this study, we report the efficacy of Leishmania donovani iron superoxide dismutase B1 (LdFeSODB1) as a vaccine antigen in BALB/c mice in a DNA-protein prime-boost immunization regimen in the presence or absence of murine granulocyte macrophage colony stimulating factor (mGMCSF) DNA adjuvant. The expression study confirmed that LdFeSODB1 is expressed in mammalian cells and mGMCSF fusion mediates the secretion of the recombinant protein. Heterologous immunization with LdFeSODB1 induced a strong antibody- and cell-mediated immune response in mice. Immunization triggered a mixed Th1/Th2 response as evidenced by the ratio of IgG2a to IgG1. Antigen-stimulated spleen cells from the immunized mice produced high level IFN-γ. Multiparametric flow cytometry data showed that immunization with LdFeSODB1 induced significantly higher expression of TNF-α or IL-2 by antigen-stimulated T cells. Eight weeks after L. major infection, immunization with the antigen shifted the immune response to a more Th1 type than the controls as demonstrated by IgG2a/IgG1 ratio. Moreover, IFN-γ production by antigen-stimulated spleen cells from immunized mice remained high. The footpad swelling experiment showed that immunization with LdFeSODB1 resulted in partial protection of mice from a high dose L. major infection.