Core genome mediated potential vaccine targets prioritization against Clostridium difficile via reverse vaccinology - an immuno-informatics approach

Abstract

The emergence of multi-drug resistance in clostridium difficile is an urgent bio-threat associated with high morbidity and mortality. The availability of core genome sequences for pathogen strains provides the opportunity to rationally approach novel therapeutic targets. No preventive vaccine against C. difficile infections is available commercially to date. The core genome data of 63 complete genome sequences of C. difficile was utilized in the current study. A precise immune informatics layout has been followed for the identification of potential vaccine target proteins that are essential for the pathogen and show no homology to human as well as human gut flora proteome. Two antigenic outer membrane proteins were prioritized for the lead epitopes prediction based on the reverse vaccinology approach. The multi-epitope chimeric vaccines were engineered using lead T cell and B cell epitopes in combination with the adjuvant peptides and linker sequences involved in enhancing the immunogenic responses. Four vaccine constructs were designed from overlapping epitopes. Based on multiple physiochemical properties, including the antigenicity, allergenicity, solubility and, molecular docking scores, the vaccine construct V2 was finalized for further analysis. The in silico restriction and cloning analysis inferred the V2 vaccine construct cloning capability within the bacterial expression system. The molecular modeling and molecular dynamic simulation showed favorable molecular interaction of V2 in the host cell and ensured the molecular stability of the V2 prioritized construct. Multi-epitope-based vaccine designing is an effective approach to develop potential therapeutics with better safety, increased potency, and logistically viable. The chimeric vaccine construct prioritized in the current study speculates to effectively bind with human immune receptor proteins and possibly triggers a potent immune response against C. difficile invasion.

Keywords

• clostridium difficile
• reverse vaccinology
• vaccine candidates
• multi-epitopes
• chimeric vaccine constructs