Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly transmittable and pathogenic human coronavirus that caused a pandemic situation of acute respiratory syndrome, called COVID-19, which has posed a significant threat to global health security. The aim of the present study is to computationally design an effective peptide-based multi-epitope vaccine (MEV) against SARS-CoV-2. The overall model quality of the vaccine candidate, immunogenicity, allergenicity, and physiochemical analysis have been conducted and validated. Molecular dynamics studies confirmed the stability of the candidate vaccine. The docked complexes during the simulation revealed that a strong and stable binding interactions of MEV with human and mice toll-like receptors (TLR), TLR3 and TLR4. Finally, candidate vaccine codons have been optimized for their in silico cloning in E.coli expression system, to confirm increased expression. The proposed MEV can be a potential candidate against SARS-CoV-2, but experimental validation is needed to ensure its safety and immunogenicity status.

West Nile Virus (WNV) is a life threatening flavivirus that causes significant morbidity and mortality worldwide. No preventive therapeutics including vaccines against WNV are available for human use. In this study, immunoinformatics approach was performed to design a multi epitope-based subunit vaccine against this deadly pathogen. Human (HLA) and Mice (H-2) allele specific potential T-cell and B-cell epitopes were shortlisted through a stringent procedure. Molecular docking showed selected epitopes that have stronger binding affinity with human TLR-4. Molecular dynamics simulation confirmed the stable nature of the docked complex. Furthermore, in silico cloning analysis ensures efficient expression of desired gene in the microbial system. Interestingly, previous studies showed that two of our selected epitopes have strong immune response against WNV. Therefore, selected epitopes could be strong vaccine candidates to prevent WNV infections in human. However, further in vitro and in vivo investigations could be strengthening the validation of the vaccine candidate against WNV.

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Legionella pneumophila, the causative agent of a serious type of pneumonia (lung infection) called Legionnaires' disease. It is emerging as an antibacterial resistant strain day by day.Hence, identification of novel drug targets and vaccine candidates is essential to fight against this pathogen. Herein attempts were taken through subtractive genomics approach on complete proteome of L. pneumophila to address the challenges of multidrug resistance. A total 2930 proteins from L. pneumophila proteome were investigated through diverse subtractive proteomics approaches, e.g., identification of human non homologous and pathogen specific essential proteins, druggability and 'anti-target' analysis, prediction of subcellular localization, human microbiome non-homology screening, protein-protein interactions studies in order to find out effective drug and vaccine targets. Only 3 were identified that fulfilled all these criteria and proposed as novel drug targets against L. pneumophila. Furthermore, outer membrane protein TolB was identified as potential vaccine target with better antigenicity score and allowed for further in silico analysis to design a unique multiepitope subunit vaccine against it. Antigenicity and transmembrane topology screening, allergenicity and toxicity assessment, population coverage analysis and molecular docking approach were adopted to generate the most potent epitopes. The final vaccine was constructed by the combination of highly immunogenic epitopes along with suitable adjuvant and linkers. The designed vaccine construct showed higher binding interaction with different MHC molecules and human immune TLR2 receptor with minimum deformability at molecular level. The translational potency and microbial expression of the vaccine protein was also analyzed using pET28a(+) vector. The present study aids in the development of novel therapeutics and vaccine candidates for efficient treatment of the infections caused by Legionella pneumophila. However, further wet lab based investigations and in vivo trials are highly recommended to experimentally validate our prediction.

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Bartonella bacilliformis is the causative agent of Carrión’s disease, one of the truly neglected tropical diseases found in Peru, Colombia and Ecuador. Recent evidence predicts that Bartonella bacilliformis subsp. ver097 can emerge as an antibacterial resistant strain and hence identification of novel drug targets is a crying need. Subtractive genome analysis of B. bacilliformis subsp. ver097 was successfully done in order to address the challenges. Various computational tools and online based servers were used to screen out human homologous proteins of pathogen and proteins involved in common metabolic pathways of host and pathogen. Only 7 proteins involved in pathogen specific pathways were further analyzed to identify membrane proteins. ‘Flagellar biosynthesis protein FlhA’ and ‘ABC transporter permease’ were found to be novel as targets according to DrugBank database. To avoid side effects in human while administering drugs, human ‘anti-targets’ analysis was performed to confirm non-homology of selected novel drug targets. Both predicted proteins also showed probability of antigenicity prediction through VaxiJen, however, ‘Flagellar biosynthesis protein FlhA’ showed broad spectrum conservancy with Bartonella strains. Therefore, Flagellar biosynthesis protein FlhAcould facilitate the development of novel drugs and therapeutic compounds along with vaccines for efficient treatment of infections caused by Bartonella bacilliformis subsp. ver097.

Legionella pneumophila is a human pathogen distributed worldwide, causing Legionnaires’ disease (LD), a severe form of pneumonia and respiratory tract infection. L. pneumophila is emerging as an antibiotic-resistant strain, and controlling LD is now difficult. Hence, developing novel drugs and vaccines against L. pneumophila is a major research priority.