KMP11-HASPB fusion protein-expressing lentiviral vaccine protects BALB/c mice against Leishmania major infection

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 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-cGFPlentiviral vector as a fusion protein to be used as a DNA vaccine against L. major. 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-gamma, 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-gamma, 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-. 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 liver of vaccinated mice after challenge was significantly lower than that of controls.