A Novel Chimeric Antigen as a Vaccine Candidate against Leishmania major: In silico Analysis.

BACKGROUND: Leishmania is a mandatory intracellular pathogen and causing neglected disease. Hence, protection against leishmaniasis by a development vaccine is an important subject. This study aimed to design a poly-epitope vaccine for cutaneous leishmaniasis. METHODS: The present study was conducted in the Parasitology Department of Tarbiat Modares University, Tehran, Iran during 2017-2019. Several bioinformatics methods at online servers were used for prediction of different aspects of poly-epitope, including, physico-chemical attributes, allergenicity, antigenicity, secondary and tertiary structures, B-cell, T-cell and MHC (I, II) potential epitopes of LACK, LEIF, GP63 and SMT antigens of L. major. RESULTS: After designing the construct (GLSL), the outputs of PTM sites demonstrated that the poly-epitope had 57 potential sites for phosphorylation. Furthermore, the secondary of GLSL structure includes 59.42%, 20.94% and 19.63% for random coil, extended strand and alpha-helix, respectively. The GLSL is an immunogenic protein with an acceptable antigenicity (0.8410) and non-allergen. Afterward, 20 potential epitopes of LACK, LEIF, GP63 and SMT antigens were linked by a flexible linker (SAPGTP), then was synthesized, and sub-cloned in pLEXY- neo2. The results were confirmed the expression of 38.7 kDa poly-epitope in secretory and cytosolic sites, separately. CONCLUSION: A good expression in the L. tarentulae and confirmation of the GLSL poly-epitope could be a basis for developing a vaccine candidate against leishmaniasis that should be confirmed via experimental tests in BALB/c mice.

A proteomic glimpse into the effect of antimalarial drugs on Plasmodium falciparum proteome towards highlighting possible therapeutic targets.

There is no effective vaccine against malaria; therefore, chemotherapy is to date the only choice to fight against this infectious disease. However, there is growing evidences of drug-resistance mechanisms in malaria treatments. Therefore, the identification of new drug targets is an urgent need for the clinical management of the disease. Proteomic approaches offer the chance of determining the effects of antimalarial drugs on the proteome of Plasmodium parasites. Accordingly, we reviewed the effects of antimalarial drugs on the Plasmodium falciparum proteome pointing out the relevance of several proteins as possible drug targets in malaria treatment. In addition, some of the P. falciparum stage-specific altered proteins and parasite-host interactions might play important roles in pathogenicity, survival, invasion and metabolic pathways and thus serve as potential sources of drug targets. In this review, we have identified several proteins, including thioredoxin reductase, helicases, peptidyl-prolyl cis-trans isomerase, endoplasmic reticulum-resident calcium-binding protein, choline/ethanolamine phosphotransferase, purine nucleoside phosphorylase, apical membrane antigen 1, glutamate dehydrogenase, hypoxanthine guanine phosphoribosyl transferase, heat shock protein 70x, knob-associated histidine-rich protein and erythrocyte membrane protein 1, as promising antimalarial drugs targets. Overall, proteomic approaches are able to partially facilitate finding possible drug targets. However, the integration of other 'omics' and specific pharmaceutical techniques with proteomics may increase the therapeutic properties of the critical proteins identified in the P. falciparum proteome.

Inter- and Intraspecific Variations of Leishmania Strains Isolated from Patients with Cutaneous and Visceral Leishmaniases in Fars Province, South of Iran.

BACKGROUND: Cutaneous and visceral leishmaniases are present in Fars Province in the south of Iran. The current study aimed to evaluate the inter- and intragenic diversities of Leishmania species isolated from patients with leishmaniasis in Fars Province, using PCR-based analyses and DNA sequencing of the N-acetylglucosamine-1-phosphate transferase (nagt) gene. METHODS: Clinical samples were taken from the skin lesions of 120 individuals with clinical suspicion of cutaneous leishmaniasis (CL) referred to the major health centers of Shiraz. Along with microscopic examination, a part of each sample was used for in vitro cultivation. DNA was extracted from the cultured parasites and the nagt gene was PCR-amplified. For RFLP analysis, the PCR product of the nagt gene was digested with the Acc1 restriction enzyme. Moreover, the PCR products of 23 isolates were sequenced and analyzed, using MEGA5. RESULTS: From the 120 patients with clinical suspicion of CL, 110 (91.7%) cases were found to be positive by direct microscopy while 77 (64.1%) of the cultures were positive. Digestion of the PCR product with the Acc1 restriction enzyme detected L. major in 57 out of the 77 (74.1%) and L. tropica, in 20 out of the 77 (25.9%) cases with CL. Phylogenetic analysis grouped the Leishmania isolates into 3 main clades, representing L. major, L. infantum, and L. tropica, encompassing 2, 2, and 2 haplotypes, respectively. Within the clades, the L. tropica intraspecies divergence was more pronounced in L. major. CONCLUSION: The findings of this study demonstrated that the causative agent of CL in Fars Province was mainly L. majorz and that there was considerable heterogeneity between the Leishmania species and also within the L. major isolates.

Expression analysis of viscerotropic leishmaniasis gene in Leishmania species by real-time RT-PCR.

UNLABELLED: Viscerotropic leishmaniasis (VTL) is a parasitic disease with non-specific manifestations caused by Leishmania tropica. Specific antigens produced by Viscerotropic leishmaniasis gene have been used for diagnosis of VTL. The aim of this study was to compare the expression level of VTL gene among the viscerotropic L. tropica isolates (n: 3) and visceral L. infantum isolates (n: 4). Also, the expression level was compared in L. tropica (n: 21) and L. major (n: 8) isolates, the main causes of cutaneous leishmaniasis in Iran by real time-RT-PCR. Results showed viscerotropic leishmaniasis gene was expressed in all 3 species; L. tropica, L. major and L. infantum. The most expression rate was in L. tropica and L. major as the cutaneous species and the lowest in visceral isolates including L. infantum and viscerotropic L. tropica strains respectively. CONCLUSION: Results revealed that VTL gene can play an important role in visceralization process of L. tropica although there are other mechanisms to keep parasite visceralized. According to these primary results, increased the expression level of VTL gene probably could contribute to inhibit the invasive behavior of Leishmania parasites. However, more experimental researches are needed to confirm this idea.