Bac to Bac System Efficiency for Preparing HPV Type 16 Virus-Like Particle Vaccine

Area of Science:

• Biotechnology
• Virology
• Molecular Biology

Background:

• The L1 protein of human papillomavirus (HPV) is a key target for prophylactic vaccines.
• Virus-like particles (VLPs) mimicking natural HPV structure are crucial for inducing neutralizing antibodies.
• Eukaryotic expression systems are vital for producing functional HPV L1 protein.

Purpose of the Study:

• To utilize the Bac-to-Bac system for generating HPV16 L1 VLPs in Spodoptera frugiperda (Sf9) insect cells.
• To optimize the industrial-level production of HPV L1 protein.
• To assess the suitability of the baculovirus/Sf9 system for recombinant protein synthesis.

Main Methods:

• Selected and codon-optimized the wild-type HPV16 L1 gene.
• Constructed a recombinant baculovirus using the pFast Bac vector and Bac-to-Bac system.
• Transfected Sf9 cells, lysed cells, and analyzed L1 protein expression via SDS-PAGE and Western Blot.
• Purified L1 protein using Ni-NTA chromatography.
• Visualized VLP formation using transmission electron microscopy.

Main Results:

• Successfully expressed recombinant HPV16 L1 protein (~60 kD) in Sf9 cells.
• Confirmed L1 protein expression using SDS-PAGE and Western Blot with a specific monoclonal antibody.
• Transmission electron microscopy verified the assembly of VLPs.
• Demonstrated the efficacy of the baculovirus/Sf9 system for HPV L1 VLP production.

Conclusions:

• The baculovirus/Sf9 expression system is a viable and promising method for producing HPV16 L1 VLPs.
• This system facilitates industrial-scale production and optimization of HPV L1 protein synthesis.
• The characterized VLPs are suitable for further development in prophylactic HPV vaccine strategies.