Evaluation of Leishmanization Using Iranian Lizard Leishmania Mixed With CpG-ODN as a Candidate Vaccine Against Experimental Murine Leishmaniasis

Abstract

Background and Objectives: The live non-pathogenic Leishmania tarantolae has recently provided a promising approach as an effective vaccine candidate against experimental leishmaniasis (ILL). Here, we evaluated the immunoprotective potential of the live Iranian Lizard Leishmania mixed with CpG adjuvant against L. major infection in BALB/c mice. Methods: Four groups of female BALB/c mice were included in the study. The first and second groups received PBS and CpG, respectively. The immunized groups received 2 × 10 5 ILL promastigotes and the CpG-mixed ILL (ILL+CpG). Injections were performed subcutaneously in the right footpad. Three weeks later, all mice were challenged with 2 × 10 5 metacyclic promastigotes of Leishmania major EGFP ; inoculation was done in the left footpad. The measurement of footpad swelling and in vivo fluorescent imaging were used to evaluate disease progress during infection course. Eight weeks after challenge, all mice were sacrificed and the cytokines levels (IFN-γ, IL-4, and IL-10) and sera antibodies concentrations (IgG2a and IgG1) using ELISA assay, nitric oxide production using Griess assay, and arginase activity in cultured splenocytes, were measured. In addition, direct fluorescent microscopy analysis and qPCR assay were used to quantify the splenic parasite burden. Result: The results showed that mice immunized with ILL+CpG were protected against the development of the dermal lesion. Moreover, they showed a significant reduction in the parasite load, in comparison to the control groups. The observed protection was associated with higher production of IFN-γ, as well as a reduction in IL-4 level. Additionally, the results demonstrated that arginase activity was decreased in ILL+CpG group compared to other groups. Conclusion: Immunization using ILL+CpG induces a protective immunity; indicating that ILL with an appropriate adjuvant would be a suitable choice for vaccination against leishmaniasis.

Leishmania tarentolae as an Antigen Delivery Platform: Dendritic Cell Maturation after Infection with a Clone Engineered to Express the SARS-CoV-2 Spike Protein

“…L. tarentolae has been investigated as a candidate vaccine, or as a vaccine vehicle, in in vivo studies on rodent models, following two major strategies. In a first approach, whole, living promastigotes were tested as vaccines against human pathogenic leishmaniae, either with [ 26 , 27 ] or without adjuvants [ 11 ]. In other studies, engineered strains of this microorganism were employed as a delivery platform, expressing antigens from a given pathogen (e.g., from pathogenic Leishmania spp.…”

Leishmania tarentolae as Potential Live Vaccine Co-Expressing Distinct Salivary Gland Proteins Against Experimental Cutaneous Leishmaniasis in BALB/c Mice Model

“…Therefore, live attenuated vaccines were introduced as the promising alternative for protection against Leishmania parasites. In parallel human nonpathogenic species such as Leishmania tarentolae have generated promising results as a live vaccine vector (25,34).…”

Leishmania tarentolae: a vaccine platform to target dendritic cells and a surrogate pathogen for next generation vaccine research in leishmaniases and viral infections

“…In that study, the promastigotes of L. tarentolae were not engineered for the expression of any antigen from pathogenic Leishmania species, nor for any proteins capable of stimulating the immune response, but only for the production of the green fluorescent protein. Live, non-engineered, promastigotes of L. tarentolae have also been shown to provide cross-protective immunity against L. major [75,76]. The possibility of exploiting wild-type L. tarentolae as a vaccine against dog or human pathogenic Leishmania species is thus worthy of further investigations (see section Concluding remarks).…”