Multi-epitope vaccine design against Clostridioides difficile using the ABC-type transport system protein

Area of Science:

• Vaccinology
• Computational Biology
• Immunology

Background:

• Clostridioides difficile infections (CDI) are a significant cause of antibiotic-associated nosocomial diarrhea, with a high incidence globally, particularly in India.
• The ABC-type transport system protein of C. difficile presents a potential target for vaccine development.

Purpose of the Study:

• To design a multi-epitope vaccine construct targeting the C. difficile ABC-type transport system protein.
• To computationally evaluate the immunogenicity, stability, and efficacy of the designed vaccine candidate.

Main Methods:

• Epitope prediction for B-cell, cytotoxic T-lymphocyte (CTL), and helper T-lymphocyte (HTL) responses using bioinformatics tools (BepiPred-2.0, NetCTL 1.2, NetMHCIIpan 4.0).
• In silico validation including antigenicity, non-allergenicity, physicochemical stability, structural modeling, molecular docking with TLR3, and molecular dynamics simulations.
• Immune simulations using C-ImmSim to predict T- and B-cell responses.

Main Results:

• A 66-amino-acid multi-epitope construct was designed using specific spacers and a TLR3 adjuvant.
• The construct demonstrated excellent structural stability (RMSD ~0.1 Å) and favorable binding affinity to TLR3.
• Immune simulations predicted robust B- and T-cell responses, with elevated levels of IFN-γ and IL-2.

Conclusions:

• The designed multi-epitope construct shows significant potential as a safe and effective prophylactic vaccine against C. difficile infections.
• The computational approach provides a strong foundation for further experimental validation and development of a C. difficile vaccine.