Abstract
BACKGROUND: Nowadays, the prevention of parasitic diseases including leishmaniasis, particularly cutaneous leishmaniasis as the smost common type of the disease, has increased health concerns around the world. Although some drugs such as Glucantim and Amphotericin B are approved, they have side effects. Therefore, treatment without side effects is a priority. METHODOLOGY: In this study, the recombinant lentiviral vaccine containing a novel multi-epitope of KMP11 and HASPB of Leishmania major (L. major) was synthesized. The multi-epitope construct was previously designed in silico, subcloned into the pCDH513 lentiviral vector, and the recombinant lentiviral multi-epitope vaccine (rLV-multi-epitope) was synthesized in HEK293T cells using the packaging vectors. 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: phosphate buffered saline (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 L. major lysate. Also, the serum level of IgG1 and IgG2a, and gamma interfron (IFN-γ) and interleukin-4 (IL-4) were assessed using enzyme-linked immunoassay (ELISA) test. RESULTS: The results of the enzyme-linked immunoassay ELISA showed that the titer of IFN-γ and IL-4 were increased in the immunized group. Also, the level of IFN-γ was higher significantly and as compared to IL-4, and as a result, the Th1 response was generated in the main group. Additionally, the humoral immune response was assessed, indicating that the titer of IgG2a and IgG1 antibodies in the sera of the immunized mice was increased compared to the control groups. Moreover, the serum level 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 revealed that immunization with the novel rLV-multi-epitope vaccine could stimulate the immune system toward Th1 by increasing the production of IFN-γ and IgG2a opsonin antibody.