Immunogenicity Evaluation of a Novel Lentiviral Vaccine Expressing Multi- Epitope Against of Leishmania Major in BALB/c Mice

Abstract

Background: Nowadays, the prevention of parasitic diseases including leishmaniasis is one of the health concerns in the world, and cutaneous leishmaniasis is the most common type of these diseases. So far, no drug or vaccine has been approved for definitive treatment of this disease.Methods: In this study, the recombinant lentiviral vaccine containing a new multi-epitope of KMP11 and HASPB of the Leishmania major (L. major) was synthesized that had previously been designed in-silico. The designed multi-epitope was subcloned into the pCDH513 lentiviral vector, and the recombinant lentiviral multi-epitope vaccine (rLV-multi-epitope) was synthesized in the HEK293T cell by the packaging vectors. Also, the Western Blotting method was used to confirm the gene expression. Then, the rLV-multi-epitope vaccine was injected twice, along with two control groups, PBS, and rLV-empty to immunize the BALB /c mice. Twenty-one days after the second injection, the splenocytes of the mice were is­­­­olated and stimulated with the Leishmania lysate.Results: The results of the enzyme-linked immunoassay (ELISA) test not only showed the titer of IFN-γ and IL-4 was increased in the immunized group compared to the controls, but also indicated that the ratio of IFN-γ to IL-4 cytokines in the main group was increased significantly. As a result, the Th1 response was generated in the main group. Moreover, the humoral immune response was assessed and the results showed that the ratio of IgG2a to IgG1 antibody in the sera of the immunized mice was increased compared to the control groups. Also, the ratio of IgG2a to IgG1 was increased in the main group. Therefore, the humoral immune response was increased, which can also have a positive effect on increasing the Th1 response.Conclusions: Our results showed that immunization by the new rLV-multi-epitope vaccine could stimulate the immune system towards the Th1 through increasing the IFN-γ production.

Development of a multi-epitope vaccine candidate for leishmanial parasites applying immunoinformatics and in vitro approaches

“…In total, the final vaccine construct consisted of 179 amino acids encompassing 10 epitopes (4 CTL, 4 HTL, and 2 LBL) that were combined through AAY and GDGDG linkers. The AAY linker enhances immunogenicity of the multi-epitope vaccine ( 35 ), while the GDGDG linker aids in the expression of the multi-epitope vaccine by virtue of their flexible (Gly) and hydrophilic (Asp) amino acid composition ( 36 ). The administration of TLR agonists as adjuvants within vaccine candidates are reported to induce strong T-cell and antibody-mediated responses ( 37 ), hence the N-terminus was appended with a TLR-4 agonist as adjuvant, i.e., RS-09 (APPHALS), using a rigid linker (EAAAK).…”