No abstract

Hydrophilic acylated surface protein B (HASPB) is an immunogenic Leishmania-specific protein that antibodies are produced against it in the sera of Leishmania-infected individuals. Kinetoplastid membrane protein 11 (KMP11) is another Leishmania antigen and considered as the suitable candidate for vaccine development Leishmaniasis. It is a highly conserved surface protein expressed in both promastigotes and amastigotes. In this study, KMP11 and HASPB coding sequences were cloned into a pCDH-cGFP lentiviral vector as a fusion protein to be used as a DNA vaccine against L. major. The KMP11-HASPB fusion protein was successfully expressed as evidenced by RT-PCR and Western blot assays. The effect of the vaccine was determined by evaluating the level of IFN-γ, IL-10, IgG1, and IgG2a performed using ELISA as well as determining the parasite load after challenge with L. major in vaccinated mice. The results revealed that IFN-γ, IL-10, IgG1, and IgG2a significantly increased after vaccination using KMP11-HASPB-expressing lentiviruses in BALB/c mice. It is noteworthy that the level of IFN-γ and IgG2a was higher than that of IL-10 and IgG1, respectively, which indicates the activation Th1 cells, macrophages, and cellular immunity. Moreover, the parasite load in the spleen and lymph node of vaccinated mice after challenge was significantly lower than that of controls.

Hydrophilic acylated surface protein B (HASPB) is an immunogenic Leishmania protein against which antibodies are produced in the sera of cutaneous and visceral Leishmaniasis (VL) patients. Kinetoplastid membrane protein 11 (KMP11) is another protein antigen of Leishmania which is reported as a promising candidate for vaccination of VL. It is a highly conserved surface protein present in all members of kinetoplastid family and is expressed in both promastigotes and amastigotes. In this study, the coding sequence of KMP11 and HASPB was cloned into a pCDH-cGFP lentiviral vector as a fusion protein. The gene expression was confirmed using RT-PCR and Western blot methods. After injection of the recombinant KMP11-HASPB-expressing lentiviruses to BALB/c mice, using ELISA technique, a significant increase in IFN-γ and IL-4 as well as IgG1 and IgG2a was observed compared to the control group. Furthermore, the number of parasites in the liver and spleen of vaccinated mice decreased significantly compared with the control group.

No 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.