Modular Virus-like Particles for Antigen Presentation: Comparing Genetic Fusion and Click-Chemistry for Purification

Area of Science:

• Biotechnology
• Vaccine Development
• Protein Engineering

Background:

• The SARS-CoV-2 pandemic highlighted the need for adaptable vaccine manufacturing technologies.
• Virus-like particles (VLPs) offer a promising platform for presenting target antigens.
• Hepatitis B Core (HBc) antigen and SplitCore (SplCo) technology were investigated as VLP scaffolds.

Purpose of the Study:

• To investigate the purification of Hepatitis B Core (HBc) virus-like particles (VLPs) fused with antigens.
• To evaluate the impact of SplitCore (SplCo) technology on VLP solubility and hydrophobicity.
• To explore the utility of click-chemistry for VLP modification and antigen conjugation.

Main Methods:

• Genetic fusion of outer surface protein C (OspC) from Borrelia burgdorferi to HBc and SplCo.
• Expression in E. coli, precipitation, solubilization, and anion exchange chromatography (AEX) for VLP purification.
• Construction of a novel HBc variant for post-translational modification via click-chemistry.

Main Results:

• SplCo-OspC fusions showed significantly increased solubility (90%) and reduced hydrophobicity compared to HBc-OspC.
• Anion exchange chromatography (AEX) yielded VLPs with low purity; dissociative purification followed by reassembly was unsuccessful.
• A modified HBc variant achieved 84% VLP yield after dissociative AEX, with successful fluorophore conjugation (up to 59%) via click-chemistry.

Conclusions:

• The combination of HBc VLPs and click-chemistry presents a viable strategy for antigen presentation and vaccine development.
• Optimizing scaffold-decoration strategies and manufacturing processes is crucial for each specific antigen.
• The SplCo technology enhances VLP solubility, while click-chemistry allows for stable modification and conjugation.