Design, Construction and Immunogenicity Assessment of pEGFP-N1-KMP11-GP96 (Fusion) as a DNA Vaccine Candidate against Leishmania major Infection in BALB/c Mice

<p><strong>BACKGROUND: </strong>KMP-11 (Kinetoplastid membrane protein-Π) exists in all species of kinetoplastid family. It is fully conserved and the protein produced by this gene can induce a very high cellular immune response. We aimed to design a suitable construction for a <em>Leishmania major</em> DNA vaccine and evaluate the protective efficacy of it as a candidate for DNA vaccine against cutaneous leishmaniasis in BALB/c mice.</p><p><strong>METHODS: </strong>This experimental study was conducted in Tehran City, Iran, between April 20, 2015 and May 30, 2016. KMP-11 gene of <em>L. major</em> (MRHO/IR/75/ER, Iranian strain) and NT-<em>GP96</em> of Xenopus <em>GP96</em> DNA from a pBluescript-<em>GP96</em> plasmid were amplified by PCR and the purified PCR products were cloned into the pJET1.2/blunt plasmid vector, then, subcloned into pEGFP-N1 plasmid as an expression vector. Finally, the KMP-11 gene was fused with <em>GP96</em> and afterward the combination cloned in pEGFP-N1. All the cloned genes confirmed by enzyme digestions. Then, four groups of mice were immunized with PBS, pEGFP-N1, pEGFP-N1-KMP, and pEGFP-N1-fusion. Four weeks after immunization, all animals were challenged with <em>L. major</em> virulent promastigotes.</p><p><strong>RESULTS: </strong>The constructed fusion potentially showed an ability to elicit Th1 responses that led to cutaneous lesion healing. Interestingly, the group received KMP11-<em>GP96</em> -GFP showed the highest ratio of IFN- γ /IL-4 and IgG2a/IgG1 compare to other groups. No side effect was observed after using the fusion in the mice.</p><p><strong>CONCLUSION: </strong>The constructed fusion could well stimulate both the cellular and humoral immune systems that led to cutaneous lesion healing in mice.</p>