A multi-subunit based, thermodynamically stable model vaccine using combined immunoinformatics and protein structure...

Area of Science:

• Vaccinology
• Immunology
• Computational Biology

Background:

• Conventional vaccines show limited efficacy in preventing Mycobacterium avium subsp. paratuberculosis (MAP) infections and their spread.
• Protein structure-based vaccine design offers a promising alternative to traditional approaches.
• Developing effective subunit vaccines requires careful selection and combination of antigenic components and adjuvants.

Purpose of the Study:

• To design and computationally evaluate a novel multi-epitope subunit vaccine against MAP.
• To enhance vaccine stability and immunogenicity through protein engineering and molecular dynamics simulations.
• To create a vaccine candidate that elicits robust cellular and humoral immune responses.

Main Methods:

• Conjugation of immunodominant peptide epitopes from MAP1611 with heparin-binding hemagglutinin (a TLR4 agonist) as an adjuvant.
• 3D homology modeling to generate the chimeric multi-epitope vaccine structure.
• Molecular dynamics simulations and disulfide engineering to assess and enhance conformational stability and identify optimal mutants.

Main Results:

• A stable, multi-epitope subunit vaccine construct was designed, incorporating T-cell and B-cell epitopes.
• Disulfide engineering yielded a double mutant (Q631C-A634C/Y593C-E610C) with enhanced thermodynamic stability.
• The final vaccine candidate is predicted to be antigenic, soluble, non-allergenic, and capable of interacting with TLR receptors.

Conclusions:

• The designed multi-epitope subunit vaccine, particularly the double mutant, shows significant potential for inducing protective Th1 cellular and humoral immunity against MAP.
• This protein structure-based strategy represents a promising platform for developing pathogen-specific vaccines.
• The approach may be adaptable for combating other infectious diseases in the future.