Structural proteomics guided annotation of vaccine targets and designing of multi-epitopes vaccine to instigate adaptive immune response against Francisella tularensis

• Published in: Microbial pathogenesis 2024-09, Vol.194, p.106777, Article 106777
• Main Authors: Khan, Abbas, Ali, Syed Shujait, Khan, Asghar, Zahid, Muhammad Ammar, Alshabrmi, Fahad M., Waheed, Yasir, Agouni, Abdelali
• Format: Article
• Language: English
• Subjects: Adaptive Immunity; Antigens, Bacterial - genetics; Antigens, Bacterial - immunology; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - immunology; Bacterial Vaccines - genetics; Bacterial Vaccines - immunology; Epitopes - immunology; Epitopes, B-Lymphocyte - genetics; Epitopes, B-Lymphocyte - immunology; Epitopes, T-Lymphocyte - genetics; Epitopes, T-Lymphocyte - immunology; Francisella novicida; Francisella tularensis - genetics; Francisella tularensis - immunology; Humans; Immune simulation; In silico cloning; Proteome; Proteomics; Subtractive proteomics; Toll-Like Receptor 2 - genetics; Toll-Like Receptor 2 - immunology; Toll-Like Receptor 2 - metabolism; Tularemia - immunology; Tularemia - microbiology; Tularemia - prevention & control; Vaccine Development; Vaccines
• ISSN: 0882-4010; 1096-1208; 1096-1208
• DOI: 10.1016/j.micpath.2024.106777

Francisella tularensis can cause severe disease in humans via the respiratory or cutaneous routes and a case fatality ratio of up to 10 % is reported due to lack of proper antibiotic treatment, while F. novicida causes disease in severely immunocompromised individuals. Efforts are needed to develop effective vaccine candidates against Francisella species. Thus, in this study, a systematic computational work frame was used to deeply investigate the whole proteome of Francisella novicida containing 1728 proteins to develop vaccine against F. tularensis and related species. Whole-proteome analysis revealed that four proteins including (A0Q492) (A0Q7Y4), (A0Q4N4), and (A0Q5D9) are the suitable vaccine targets after the removal of homologous, paralogous and prediction of subcellular localization. These proteins were used to predict the T cell, B cell, and HTL epitopes which were joined together through suitable linkers to construct a multi-epitopes vaccine (MEVC). The MEVC was found to be highly immunogenic and non-allergenic while the physiochemical properties revealed the feasible expression and purification. Moreover, the molecular interaction of MEVC with TLR2, molecular simulation, and binding free energy analyses further validated the immune potential of the construct. According to Jcat analysis, the refined sequence demonstrates GC contents of 41.48 % and a CAI value of 1. The in-silico cloning and optimization process ensured compatibility with host codon usage, thereby facilitating efficient expression. Computational immune simulation studies underscored the capacity of MEVC to induce both primary and secondary immune responses. The conservation analysis further revealed that the selected epitopes exhibit 100 % conservation across different species and thus provides wider protection against Francisella. •Francisella novicida can cause severe disease in humans via the respiratory or cutaneous routes.•Investigation of the whole-proteome revealed four proteins as suitable vaccine targets.•We designed a multi-epitopes vaccine (MEVC) from T cell, B cell, and HTL epitopes.•Molecular docking, simulation, in silico cloning and immune simulation confirmed the potential of our MEVC.•Our MEVC could also provide cross-protection against the other species of Francisella.