Open Access Research

Murine immune responses to a Plasmodium vivax-derived chimeric recombinant protein expressed in Brassica napus

Choonghee Lee1, Hyung-Hwan Kim27, Kyung Mi Choi13, Kyung Won Chung1, Yien Kyoung Choi13, Mi Jung Jang1, Tong-Soo Kim4, Nam-Jun Chung5, Ho-Gun Rhie1, Ho-Sa Lee1, Youngjoo Sohn6, Hyuck Kim7, Sung-Jae Lee1* and Hyeong-Woo Lee38*

Author Affiliations

1 Institute of Global Environment and Department of Biology, Kyung Hee University, Seoul 130-701, Republic of Korea

2 Vascular Medicine Research Unit, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139, USA

3 Division of Malaria and Parasitic Diseases, National Institute of Health, Korea Centers for Disease Control and Prevention, Cheongwon-gun 363-951, Republic of Korea

4 Department of Parasitology, College of Medicine, Inha University, Incheon 405-751, Republic of Korea

5 Institute of Biological Resources, Callus Co., Ltd. Gwangju 500-420, Republic of Korea

6 Department of Gynecology, College of Oriental Medicine, Sangji University, Wonju 220-717, Republic of Korea

7 International Research Center for Bioscience and Biotechnology, Jungwon University, Goesan 367-805, Republic of Korea

8 Department of Pathology, University of Florida, J-566, 1600 SW Archer Road, Gainesville, FL 32610, USA

For all author emails, please log on.

Malaria Journal 2011, 10:106  doi:10.1186/1475-2875-10-106

Published: 29 April 2011

Abstract

Background

To develop a plant-based vaccine against Plasmodium vivax, two P. vivax candidate proteins were chosen. First, the merozoite surface protein-1 (MSP-1), a major asexual blood stage antigen that is currently considered a strong vaccine candidate. Second, the circumsporozoite protein (CSP), a component of sporozoites that contains a B-cell epitope.

Methods

A synthetic chimeric recombinant 516 bp gene encoding containing PvMSP-1, a Pro-Gly linker motif, and PvCSP was synthesized; the gene, named MLC, encoded a total of 172 amino acids. The recombinant gene was modified with regard to codon usage to optimize gene expression in Brassica napus. The Ti plasmid inducible gene transfer system was used for MLC chimeric recombinant gene expression in B. napus. Gene expression was confirmed by polymerase chain reaction (PCR), beta-glucuronidase reporter gene (GUS) assay, and Western blot.

Results

The MLC chimeric recombinant protein expressed in B. napus had a molecular weight of approximately 25 kDa. It exhibited a clinical sensitivity of 84.21% (n = 38) and a clinical specificity of 100% (n = 24) as assessed by enzyme-linked immunosorbent assay (ELISA). Oral immunization of BALB/c mice with MLC chimeric recombinant protein successfully induced antigen-specific IgG1 production. Additionally, the Th1-related cytokines IL-12 (p40), TNF, and IFN-γ were significantly increased in the spleens of the BALB/c mice.

Conclusions

The chimeric MLC recombinant protein produced in B. napus has potential as both as an antigen for diagnosis and as a valuable vaccine candidate for oral immunization against vivax malaria.