Leishmania infantum LeIF and its recombinant polypeptides induce the maturation of dendritic cells in vitro: An insight for dendritic cells based vaccine

CRM197-conjugated peptides vaccine of HCMV pp65 and gH induce maturation of DC and effective viral-specific T cell responses

Human cytomegalovirus (HCMV) infection is prevalent worldwide, and there is currently no licenced HCMV vaccine to control it. Therefore, developing an effective HCMV vaccine is a significant priority. Because of their excellent immunogenicity, the crucial components of HCMV, phosphoprotein 65 (pp65) and glycoproteins H (gH) are potential target proteins for HCMV vaccine design. In this study, we predicted and screened the dominant antigenic epitopes of B and T cells from pp65 and gH conjugated with the carrier protein cross-reacting material 197 (CRM197) to form three peptide-CRM197 vaccines (pp65-CRM197, gH-CRM197, and pp65-CRM197+gH-CRM197). Furthermore, the immunogenicity of the peptide-CRM197 vaccines and their effects on dendritic cells (DCs) were explored. The results showed that three peptide-CRM197 vaccines could induce maturation of DCs through the p38 MAPK signalling pathway and promote the release of proinflammatory factors, such as TNF-α and interleukin (IL) -6. Meanwhile, the peptide-CRM197 vaccines could effectively activate T cell and humoral immunity, which were far better than the inactivated HCMV vaccine. In conclusion, we constructed three peptide-CRM197 vaccines, which could induce multiple immune effects, providing a novel approach for HCMV vaccine design.

Anti-leishmanial therapy: Caught between drugs and immune targets

Leishmaniasis is an enigmatic disease that has very restricted options for chemotherapy and none for prophylaxis. As a result, deriving therapeutic principles for curing the disease has been a major objective in Leishmania research for a long time. Leishmania is a protozoan parasite that lives within macrophages by subverting or switching cell signaling to the pathways that ensure its intracellular survival. Therefore, three groups of molecules aimed at blocking or eliminating the parasite, at least, in principle, include blockers of macrophage receptor- Leishmania ligand interaction, macrophage-activating small molecules, peptides and cytokines, and signaling inhibitors or activators. Macrophages also act as an antigen-presenting cell, presenting antigen to the antigen-specific T cells to induce activation and differentiation of the effector T cell subsets that either execute or suppress anti-leishmanial functions. Three groups of therapeutic principles targeting this sphere of Leishmania-macrophage interaction include antibodies that block pro-leishmanial response of T cells, ligands that activate anti-leishmanial T cells and the antigens for therapeutic vaccines. Besides these, prophylactic vaccines have been in clinical trials but none has succeeded so far. Herein, we have attempted to encompass all these principles and compose a comprehensive review to analyze the feasibility and adoptability of different therapeutics for leishmaniasis.

DnaJ, a promising vaccine candidate against Ureaplasma urealyticum infection

Abstract

Ureaplasma urealyticum (U. urealyticum, Uu) is a common sexually transmitted pathogen that is responsible for diseases such as non-gonococcal urethritis, chorioamnionitis, and neonatal respiratory diseases. The rapid emergence of multidrug-resistant bacteria threatens the effective treatment of Uu infections. Considering this, vaccination could be an efficacious medical intervention to prevent Uu infection and disease. As a highly conserved molecular chaperone, DnaJ is expressed and upregulated by pathogens soon after infection. Here, we assessed the vaccine potential of recombinant Uu-DnaJ in a mouse model and dendritic cells. Results showed that intramuscular administration of DnaJ induced robust humoral- and T helper (Th) 1 cell-mediated immune responses and protected against genital tract infection, inflammation, and the pathologic sequelae after Uu infection. Importantly, the DnaJ protein also induced the maturation of mouse bone marrow–derived dendritic cells (BMDCs), ultimately promoting naïve T cell differentiation toward the Th1 phenotype. In addition, adoptive immunization of DnaJ-pulsed BMDCs elicited antigen-specific Immunoglobulin G2 (IgG2) antibodies as well as a Th1-biased cellular response in mice. These results support DnaJ as a promising vaccine candidate to control Uu infections.

Key points

• A novel recombinant vaccine was constructed against U. urealyticum infection.

• Antigen-specific humoral and cellular immune responses after DnaJ vaccination.

• Dendritic cells are activated by Uu-DnaJ, which results in a Th1-biased immune response.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00253-022-12230-4.

Cloning, high-level gene expression and bioinformatics analysis of SP15 and LeIF from Leishmania major and Iranian Phlebotomus papatasi saliva as single and novel fusion proteins: a potential vaccine candidate against leishmaniasis

BACKGROUND

Early exacerbation of cutaneous leishmaniasis is mainly affected by both the salivary and Leishmania parasite components. Little is known of the vaccine combination made by immunogenic proteins of sandfly saliva (SP15) with Leishmania parasites (LeIF) as a single prophylactic vaccine, namely SaLeish. Also, there are no data available to determine the species-specific sequence of SP15 isolated from the Iranian Phlebotomus papatasi.

METHODS

Integrated bioinformatics and genetic engineering methods were employed to design, optimize and obtain a vector-parasite-based vaccine formulation in a whole-length fusion form of LeIF-SP15 against leishmaniasis. Holistic gene optimization was initially performed to obtain a high yield of pure 'whole-SaLeish' expression using bioinformatics analyses. Genomic and salivary gland RNAs of wild-caught P. papatasi were extracted and their complementary DNA was amplified and cloned into pJET vector.

RESULTS

The new chimeric protein of whole-SaLeish and randomly selected transcripts of native PpIRSP15 (GenBank accession nos. MT025054 and MN938854, MN938855 and MN938856) were successfully expressed, purified and validated by immunoblotting assay. Furthermore, despite the single amino acid polymorphisms of PpIRSP15 found at positions Y23 and E73 within the population of wild Iranian sandflies, antigenicity and conservancy of PpIRSP15 epitopes remained constant to activate T cells.

CONCLUSIONS

The SaLeish vaccine strategy takes advantage of a plethora of vector-parasite immunogenic proteins with potential protective efficacy to stimulate both the innate and specific cellular immune responses against Leishmania parasites.

Species diversity and spatial distribution of CL/VL vectors: assessing bioclimatic effect on expression plasticity of genes possessing vaccine properties isolated from wild-collected sand flies in endemic areas of Iran

Background

Leishmaniasis is one of the ten most important neglected tropical diseases worldwide. Understanding the distribution of vectors of visceral and cutaneous leishmaniasis (VL/CL) is one of the significant strategic frameworks to control leishmaniasis. In this study, the extent of the bioclimatic variability was investigated to recognize a rigorous cartographic of the spatial distribution of VL/CL vectors as risk-maps using ArcGIS modeling system. Moreover, the effect of bioclimatic diversity on the fold change expression of genes possessing vaccine traits (SP15 and LeIF) was evaluated in each bioclimatic region using real-time PCR analysis.

Methods

The Inverse Distance Weighting interpolation method was used to obtain accurate geography map in closely-related distances. Bioclimatic indices were computed and vectors spatial distribution was analyzed in ArcGIS10.3.1 system. Species biodiversity was calculated based on Shannon diversity index using Rv.3.5.3. Expression fold change of SP15 and LeIF genes was evaluated using cDNA synthesis and RT-qPCR analysis.

Results

Frequency of Phlebotomus papatasi was predominant in plains areas of Mountainous bioclimate covering the CL hot spots. Mediterranean region was recognized as an important bioclimate harboring prevalent patterns of VL vectors. Semi-arid bioclimate was identified as a major contributing factor to up-regulate salivary-SP15 gene expression (P = 0.0050, P < 0.05). Also, Mediterranean bioclimate had considerable effect on up-regulation of Leishmania-LeIF gene in gravid and semi-gravid P. papatasi population (P = 0.0109, P < 0.05).

Conclusions

The diversity and spatial distribution of CL/VL vectors associated with bioclimatic regionalization obtained in our research provide epidemiological risk maps and establish more effectively control measures against leishmaniasis. Oscillations in gene expression indicate that each gene has its own features, which are profoundly affected by bioclimatic characteristics and physiological status of sand flies. Given the efficacy of species-specific antigens for vaccine production, it is essential to consider bioclimatic factors that have a fundamental role in affecting the regulatory regions of environmentally responsive loci for genes used in vaccine design.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06129-0.

Bioinformatics analyses of immunogenic T-cell epitopes of LeIF and PpSP15 proteins from Leishmania major and sand fly saliva used as model antigens for the design of a multi-epitope vaccine to control leishmaniasis

Leishmaniasis is caused by protozoan parasites belonging to 20 Leishmania species. This infectious disease is transmitted by bites of infected phlebotomine sandflies, and is widespread in 97 countries throughout the world. No preventive or effective vaccine has been developed yet. In this study, diverse computational methods were integrated to calculate evolutionary divergence, immunogenicity, IFN-γ production, epitope conservancy, and population coverage of protein fusion models of LeIF-SP15 namely SaLeish. Immunogenicity of LeIF of Leishmania species and SP15 of sandfly saliva has not been investigated in-silico in fusion form. A complete set of 9-mer MHC class I and 15-mer MHC class II peptides were identified with a high affinity for the antigenic epitopes of SaLeish inducing specific responses of CD8⁺ and CD4⁺ T cells from BALB/c and human. Our preferred approach was determining truncated fragment of SaLeish rather than a whole length bearing the capacity to trigger specific immune response. Phylogenetic analysis showed that LeIF protein is under balancing selection and is conserved between different Leishmania species. Selected SaLeish model contained 19 and 35 antigenic peptides for MHC class I and II, respectively, with strong binding affinity to both highly frequent HLA-I and HLA-II alleles. Analysis of class I CTL epitopes showed that promiscuous peptides of KSLKADIRK, MSCIPHCKY, LQAGVIVAV, and YQYYGFVAM have greater affinity to interact with HLA-A*01:01, HLA-A*02 (03, 06), HLA-A*30:02, HLA-B*40:01, and HLA-B*52:01 molecules. Population coverage with a range of 78-85% confirmed SaLeish-Model4 as an appropriate vaccine candidate among Persian, South Asia, Europe, and North America population. Also, predicted antigenic epitopes of AKPEIRTFSNVLIKY, TRVQDDLRKLQAGVI, and VALFSATMPEEVLEL corresponding to MHC class II were found to provide strong ability to produce IFNγ toward TH(1)-biased-DTH responses. Findings of the current investigation warrant the future experimental assessment of promising SaLeish prophylaxis vaccine that is capable to enhance both innate and specific cellular immune responses.