Computational structure-based approach to study chimeric antigens using a new protein scaffold displaying foreign...

Area of Science:

• Structural biology
• Vaccine development
• Protein engineering

Background:

• Recombinant production of pathogen outer membrane proteins for vaccines is challenging due to hydrophobic regions.
• Only extracellular loops of membrane proteins are typically exposed to the immune system.
• Developing effective protein-based vaccines requires functional antigen identification and production.

Purpose of the Study:

• To engineer a novel protein scaffold for displaying pathogen extracellular loops.
• To identify immunogenic epitopes from Neisseria gonorrhoeae membrane proteins.
• To develop a generalized computational approach for epitope design and dissection.

Main Methods:

• Computational structure-based design of scaffold and model antigens.
• Engineering chimeric proteins using Domain 3 (D3) scaffold and Neisseria gonorrhoeae extracellular loops.
• Characterization of chimeric proteins for solubility, stability, and epitope display.
• X-ray crystallography to confirm epitope structure.

Main Results:

• Successfully produced soluble chimeric D3 proteins displaying extracellular loops of PorB.1b and OpaB.
• Identified the most immunogenic extracellular loops from PorB.1b and OpaB.
• Obtained crystal structure of a chimeric D3 displaying an immunodominant loop, confirming structural integrity.
• Demonstrated D3 as a viable scaffold for epitope insertion and display.

Conclusions:

• Domain 3 (D3) serves as a novel and effective protein scaffold for displaying pathogen epitopes.
• Antigen dissection and chimeric protein strategies facilitate the identification of immunogenic epitopes.
• This approach offers a promising alternative to producing challenging whole membrane proteins for vaccine development.