Multi-epitope vaccine design against leishmaniasis using IFN-γ inducing epitopes from immunodominant gp46 and gp63 proteins

There is no currently approved human vaccine against leishmaniasis. Utilization of immunogenic antigens and their epitopes capable of enhancing immune responses against leishmaniasis is a crucial step for rational in silico vaccine design. The objective of this study was to generate and evaluate a potential vaccine candidate against leishmaniasis, designed by immunodominant proteins from gp46 and gp63 of Leishmania major, which can stimulate helper T-lymphocytes (HTL) and cytotoxic T-lymphocytes (CTL). For this aim, the IFN-γ-inducing MHC-I and MHC-II binders were predicted for each examined protein (gp46 and gp63) and connected with appropriate linkers, along with an adjuvant (Mycobacterium tuberculosis L7/L12) and a histidine tag. The vaccine's stability, antigenicity, structure, and interaction with the TLR-4 receptor were evaluated in silico. The resulting chimeric vaccine was composed of 344 amino acids and had a molecular weight of 35.64 kDa. Physico-chemical properties indicated that it was thermotolerant, soluble, highly antigenic, and non-allergenic. Predictions of the secondary and tertiary structures were made, and further analyses confirmed that the vaccine construct could interact with the human TLR-4 receptor. Virtual immune simulation demonstrated strong stimulation of T-cell responses, particularly by an increase in IFN-γ, following vaccination. In summary, the in silico data indicated that the vaccine candidate showed high antigenicity in humans. It was also found to trigger significant levels of clearance mechanisms and other components of the cellular immune profile. Nevertheless, further wet experiments are required to properly assess the efficacy of this multi-epitope vaccine candidate against leishmaniasis.

Immunoinformatic Analysis of Leishmania Major gp46 Protein and Potential Targets for Vaccination against Leishmaniasis

BACKGROUND

Cutaneous leishmaniasis (CL) is a parasitic disease with a significant burden in the Old World countries.

OBJECTIVE

In the current study, some of the primary biochemical properties and IFN-γ inducing epitopes with specific binding capacity to human and mouse MHC alleles were predicted for Leishmania major gp46 antigenic protein.

METHODS

Several online servers were used to predict physico-chemical traits, allergenicity, antigenicity, transmembrane domain and signal peptide, subcellular localization, post-translational modifications (PTMs), secondary and tertiary structures, tertiary model refining with validations. Also, IEDB web server was used to predict mouse/human cytotoxic T-lymphocyte (CTL) and helper T-lymphocyte (HTL) epitopes.

RESULTS

The 33.25 kDa protein was stable, hydrophilic, antigenic, while non-allergenic, with enhanced thermotolerance and 45 PTM sites. The secondary structure encompassed a random coil, followed by extended strands and helices. Ramachandran-based analysis of the refined model showed 73.1%, 21.6%, 3.4% and 1.9% of residues in the most favored, additional allowed, generously-allowed and disallowed regions, respectively. Epitope screening demonstrated 4 HTL epitopes against seemingly protective HLA alleles, 5 HTL epitopes against the HLA reference set, 3 human CTL epitopes and a number of mouse MHC-restricted epitopes.

CONCLUSION

This paper provides insights into the bioinformatics characteristics of the L. major gp46 protein as a promising vaccine candidate.

Engineering and design of promising T-cell-based multi-epitope vaccine candidates against leishmaniasis

Cutaneous leishmaniasis (CL) is a very common parasitic infection in subtropical areas worldwide. Throughout decades, there have been challenges in vaccine design and vaccination against CL. The present study introduced novel T-cell-based vaccine candidates containing IFN-γ Inducing epitopic fragments from Leishmania major (L. major) glycoprotein 46 (gp46), cathepsin L-like and B-like proteases, histone H2A, glucose-regulated protein 78 (grp78) and stress-inducible protein 1 (STI-1). For this aim, top-ranked human leukocyte antigen (HLA)-specific, IFN-γ Inducing, antigenic, CD4+ and CD8+ binders were highlighted. Four vaccine candidates were generated using different spacers (AAY, GPGPG, GDGDG) and adjuvants (RS-09 peptide, human IFN-γ, a combination of both, Mycobacterium tuberculosis Resuscitation promoting factor E (RpfE)). Based on the immune simulation profile, those with RS-09 peptide (Leish-App) and RpfE (Leish-Rpf) elicited robust immune responses and their tertiary structure were further refined. Also, molecular docking of the selected vaccine models with the human toll-like receptor 4 showed proper interactions, particularly for Leish-App, for which molecular dynamics simulations showed a stable connection with TLR-4. Upon codon optimization, both models were finally ligated into the pET28a( +) vector. In conclusion, two potent multi-epitope vaccine candidates were designed against CL and evaluated using comprehensive in silico methods, while further wet experiments are, also, recommended.

The association between psoriasis and diabetes mellitus: A systematic review and meta-analysis

BACKGROUND

Psoriasis is an immune-mediated chronic inflammatory skin disease with unknown etiology. Current findings demonstrate that psoriatic patients are at higher risk of other systemic disorders such as diabetes mellitus. The present study was conducted to evaluate the association between psoriasis and diabetes mellitus.

METHOD

The current study was conducted based on preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines. Using MeSH keywords we searched online databases of PubMed, Scopus, Web of Science, Science Direct, Embase, CINAHL, Cochrane Library, EBSCO and Google scholar search engine and the reference list of the retrieved articles until June 2018. Heterogeneity among studies was assessed using Cochran's Q test and I² index and the random effects model was used to estimate Odds Ratio (OR) and 95% confidence interval (CI). Data were analyzed using Comprehensive Meta-Analysis (CMA) software version 2.

RESULTS

Analysis of 38 eligible studies involving 922870 cases and 12808071 controls suggested the estimated OR to be 1.69 (95% Confidence Interval [CI]: 1.51-1.89; P < 0.001). Subgroup analysis was conducted based on study design and country of study and was significant (test for subgroup differences: P = 0.025 and P < 0.001, respectively).

CONCLUSIONS

Our study indicated the significant association between psoriasis and diabetes. Therefore, psoriasis is a systemic disorder and other comorbidities should be considered in the management of patients with psoriasis.