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

<p>Abstract</p> <p>Background</p> <p>To develop a plant-based vaccine against <it>Plasmodium vivax</it>, two <it>P. vivax </it>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.</p> <p>Methods</p> <p>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 <it>Brassica napus</it>. The Ti plasmid inducible gene transfer system was used for <it>MLC </it>chimeric recombinant gene expression in <it>B. napus</it>. Gene expression was confirmed by polymerase chain reaction (PCR), beta-glucuronidase reporter gene (GUS) assay, and Western blot.</p> <p>Results</p> <p>The MLC chimeric recombinant protein expressed in <it>B. napus </it>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.</p> <p>Conclusions</p> <p>The chimeric MLC recombinant protein produced in <it>B. napus </it>has potential as both as an antigen for diagnosis and as a valuable vaccine candidate for oral immunization against vivax malaria.</p