Immunoinformatics mapping of potential epitopes in SARS-CoV-2 structural proteins

All approved coronavirus disease 2019 (COVID-19) vaccines in current use are safe, effective, and reduce the risk of severe illness. Although data on the immunological presentation of patients with COVID-19 is limited, increasing experimental evidence supports the significant contribution of B and T cells towards the resolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Despite the availability of several COVID-19 vaccines with high efficacy, more effective vaccines are still needed to protect against the new variants of SARS-CoV-2. Employing a comprehensive immunoinformatic prediction algorithm and leveraging the genetic closeness with SARS-CoV, we have predicted potential immune epitopes in the structural proteins of SARS-CoV-2. The S and N proteins of SARS-CoV-2 and SARS-CoVs are main targets of antibody detection and have motivated us to design four multi-epitope vaccines which were based on our predicted B- and T-cell epitopes of SARS-CoV-2 structural proteins. The cardinal epitopes selected for the vaccine constructs are predicted to possess antigenic, non-allergenic, and cytokine-inducing properties. Additionally, some of the predicted epitopes have been experimentally validated in published papers. Furthermore, we used the C-ImmSim server to predict effective immune responses induced by the epitope-based vaccines. Taken together, the immune epitopes predicted in this study provide a platform for future experimental validations which may facilitate the development of effective vaccine candidates and epitope-based serological diagnostic assays.

Immunoinformatics approaches to design: A novel multi-epitope vaccine candidate against SARS-CoV-2 and it’s in silico expression (Preprint)

BACKGROUND SARS-CoV-2, belonging to the Coronaviridae family, is a novel RNA virus, known for causing fatal disease in humans called COVID-19. Researchers all around the world are keen on developing a precise treatment or vaccine against this deadly disease. OBJECTIVE The main objective of this paper is to design a novel multi-epitope vaccine candidate against SARS-CoV-2 using immunoinformatics tools. METHODS A consensus sequence was generated from various genomes of SARS-Cov-2 available from various countries of the outbreak at the ViPR database using JalView software. T cell and B cell epitopes were predicted by restricting them to certain HLA alleles using various servers (nHLApred, NetMHCIIpan v.3.1, ABCpred) and were validated using IEDB tools. Using these epitopes and adjuvant, a multi-epitope vaccine was constructed in-silicoand was later subjected to allergenicity, antigenicity and physicochemical properties profiling along with identification of conformational B-cell epitopes. The designed vaccine was evaluated via codon optimization by the Jcat server and finally, it’s in-silicoexpression was done in pET-28a(+) vector using snap-gene software. RESULTS A total of 18 epitopes (both T and B cell) were predicted that constituted vaccine construct along with adjuvant and end tag. Vaccine construct was validated and its best structure model was successfully docked with human Toll-like receptors. In-silico expression of the designed vector was also seen in pET-28a(+) plasmid. CONCLUSIONS The designed novel vaccine candidate has been validated in-silico to elicit robust immune responses hence; it can be used as a potential model for further development of multi-epitope vaccines in the laboratory.

Exploring the structural basis to develop efficient multi-epitope vaccines displaying interaction with HLA and TAP and TLR3 molecules to prevent NIPAH infection, a global threat to human health

Nipah virus (NiV) is an emerging zoonotic virus responsible to cause several serious outbreaks in South Asian region with high mortality rate of 40 to 90% since 2001. NiV infection causes lethal encephalitis and respiratory disease with the symptom of endothelial cell-cell fusion. No specific vaccine has yet been reported against NiV infection. Recently, some Multi-Epitope Vaccines (MEV) has been proposed but they involve limited number of epitopes which further limits the potential of vaccine. To address the urgent need for a specific and effective vaccine against NiV infection, in the present study, we have design two multi-epitope vaccines (MEVs) composed of 33 Cytotoxic T lymphocyte (CTL) epitopes and 38 Helper T lymphocyte (HTL) epitopes. Both the MEVs carry potential B cell linear epitope overlapping regions, B cell discontinuous epitopes as well as IFN-γ inducing epitopes. Hence the designed MEVs carry potential to elicit cell-mediated as well as humoral immune response. Selected CTL and HTL epitopes were validated for their stable molecular interactions with HLA class I and II alleles as well as in case of CTL epitopes, with human transporter associated with antigen processing (TAP). Human β-defensin 2 and β-defensin 3 were used as adjuvants to enhance the immune response of both the MEVs. The molecular dynamics simulation study of MEVs-TLR3(ECD) (Toll-Like Receptor 3 Ectodomain) complex indicated stable molecular interaction. Further, the codon optimized cDNA of both the MEVs has shown high expression potential in the mammalian host cell line (Human). Hence for further studies, both the design of CTL and HTL MEVs could be cloned, expressed and tried for in-vivo validations (animal trails) as potential vaccine candidates against NiV infection.

Development of PDA Nanoparticles for H9N2 Avian Influenza BPP-V/BP-IV Epitope Peptide Vaccines: Immunogenicity and Delivery Efficiency Improvement

The protection of current influenza vaccines is limited due to the viral antigenic shifts and antigenic drifts. The universal influenza vaccine is a new hotspot in vaccine research that aims to overcome these problems. Polydopamine (PDA), a versatile biomaterial, has the advantages of an excellent biocompatibility, controllable particle size, and distinctive drug loading approach in drug delivery systems. To enhance the immunogenicities and delivery efficiencies of H9N2 avian influenza virus (AIV) epitope peptide vaccines, PDA nanoparticles conjugated with the BPP-V and BP-IV epitope peptides were used to prepare the nano BPP-V and BP-IV epitope peptide vaccines, respectively. The characteristics of the newly developed epitope peptide vaccines were then evaluated, revealing particle sizes ranging from approximately 240 to 290 nm (PDI<0.3), indicating that the synthesized nanoparticles were stable. Simultaneously, the immunoprotective effects of nano BPP-V and BP-IV epitope peptide vaccines were assessed. The nano BPP-V and BP-IV epitope vaccines, especially nano BP-IV epitope vaccine, quickly induced anti-hemagglutinin (HA) antibody production and a sustained immune response, significantly promoted humoral and cellular immune responses, reduced viral lung damage and provided effective protection against AIV viral infection. Together, these results reveal that PDA, as a delivery carrier, can improve the immunogenicities and delivery efficiencies of H9N2 AIV nano epitope vaccines, thereby providing a theoretical basis for the design and development of PDA as a carrier of new universal influenza vaccines.

Bioinformatics Prediction of SARS-CoV-2 Epitopes as Vaccine Candidates for the Colombian Population

Coronavirus disease (COVID-19) pandemic caused by the coronavirus SARS-CoV-2 represents an enormous challenge to global public health, with thousands of infections and deaths in over 200 countries worldwide. The purpose of this study was to identify SARS-CoV-2 epitopes with potential to interact in silico with the alleles of the human leukocyte antigen class I (HLA I) and class II (HLA II) commonly found in the Colombian population to promote both CD4 and CD8 immune responses against this virus. The generation and evaluation of the peptides in terms of HLA I and HLA II binding, immune response, toxicity and allergenicity were performed by using computer-aided tools, such as NetMHCpan 4.1, NetMHCIIpan 4.0, VaxiJem, ToxinPred and AllerTop. Furthermore, the interaction between the predicted epitopes with HLA I and HLA II proteins frequently found in the Colombian population was studied through molecular docking simulations in AutoDock Vina and interaction analysis in LigPlot+. One of the promising peptides proposed in this study is the HLA I epitope YQPYRVVVL, which displayed an estimated coverage of over 82% and 96% for the Colombian and worldwide population, respectively. These findings could be useful for the design of new epitope-vaccines that include Colombia among their population target.

A Candidate Multi-epitope Vaccine Against Porcine Reproductive and Respiratory Syndrome Virus and Mycoplasma Hyopneumoniae

Background: Porcine reproductive and respiratory syndrome virus (PRRSV) and Mycoplasma hyopneumoniae (M. hyopneumoniae, Mhp) are two of the most common pathogens involved in the porcine respiratory disease complex (PRDC) which results in significant worldwide economic losses. Vaccination is reported to be the most effective approach to prevent the disease. Since PRRSV and Mhp co-infections are very common, an efficient dual vaccine against PRRSV and Mhp co-infections is required for the global swine industry. Compare with the traditional vaccine, the multi-epitope vaccines have several advantages, such as comparatively easy production and construction, chemical stability, and lack of infectious potential.Results: In this study, to develop a safe and effective vaccine, B cell epitopes and T cell epitopes of PRRSV-GP5, PRRSV-M, Mhp-P46 and Mhp-P65 protein had been screened to construct a recombinant epitope protein rEP-PM which has good hydrophilicity, strong antigenicity and high surface accessibility, and each epitope is independent and complete. After immunization in mice, rEP-PM could induce the production of high levels of antibodies and effective cellular immune response.Conclusions: Our results showed that the rEP-PM protein could be potential candidate to develop into a safe and effective multi-epitope peptide combined vaccine used in the control of PRRSV and Mhp infection.

Predicting Multi-Epitope Peptide Cancer Vaccine from Novel TAA Topo48

Cancer is one of the most lethal diseases. Recently, cancer immunotherapy has a tremendous achievement in cancer treatment. A certain number of cancer based epitope vaccines with different moiety have been discovered. In japan, several clinical tests of cancer based epitope vaccine derived from tumor associated antigens (TAAs) are now ongoing or have recently been completed. a novel of TAAs potentially as cancer vaccine have been retrieved from a fragment weighed 48kDa derived from human DNA-topoisomerase 1 (TOP1) called Topo48. Therefore, it is still critical to discover a derived Topo48 epitope based cancer vaccine. Immuno-informatics considered as a methods noted to have better accuracy to design promising vaccine candidates. Here, continuous and discontinuous B-cell epitopes following with CTL epitopes and their docking interaction to major histocompatibility complex (MHC) class I Human Leukocyte Antigens (HLA)- A0201 were predicted. Kolaskar-Tongaonkar’s, Emini’s, Karpus-Schulz’s, and Parker’s methods were used to predict continuous B-cell epitopes while ElliPro was used for prediction of discontinued B-cell epitopes. Those considered methods marked to have better accuracy to design promising vaccine candidates. Similarly, CTL epitopes was also predicted by using NetCTL server and the best candidates were further investigated their binding affinity by mean of PEP-FOLD3, PatchDock rigid-body docking server, and FireDock server. Total 27 continuous epitopes and 7 discontinuous B-cell epitopes were predicted. In the other hand, 9 peptides were predicted as CTL epitopes. Whereas, three predicted CTL epitope in range 263MLDHEYTTK27, 755AIDMADEDY763, 715ALGTSKLNY724) exhibited good interactions to HLA-A0201. Moreover, we also found residues His266, Thr270, Ala755, Tyr723, Thr718, Ser719, Lys720 from Topo48 and residues Thr163, Asp757, His70, Glu63 from HLA- A0201 were indicated to be antigenic. Ultimately, our proposed continuous/discontinuous B-cell epitopes, and also CTL epitopes can be potential vaccines for cancer immunotherapy.

Quantifying the Persistence of Vaccine-Related T Cell Epitopes in Circulating Swine Influenza A Strains from 2013–2017

When swine flu vaccines and circulating influenza A virus (IAV) strains are poorly matched, vaccine-induced antibodies may not protect from infection. Highly conserved T cell epitopes may, however, have a disease-mitigating effect. The degree of T cell epitope conservation among circulating strains and vaccine strains can vary, which may also explain differences in vaccine efficacy. Here, we evaluate a previously developed conserved T cell epitope-based vaccine and determine the persistence of T cell epitope conservation over time. We used a pair-wise homology score to define the conservation between the vaccine’s swine leukocyte antigen (SLA) class I and II-restricted epitopes and T cell epitopes found in 1272 swine IAV strains sequenced between 2013 and 2017. Twenty-four of the 48 total T cell epitopes included in the epitope-based vaccine were highly conserved and found in >1000 circulating swine IAV strains over the 5-year period. In contrast, commercial swine IAV vaccines developed in 2013 exhibited a declining conservation with the circulating IAV strains over the same 5-year period. Conserved T cell epitope vaccines may be a useful adjunct for commercial swine flu vaccines and to improve protection against influenza when antibodies are not cross-reactive.