Establishment of a novel method without sequence modification for developing NoV P particle-based chimeric vaccines.

Area of Science:

• Vaccinology
• Structural biology
• Virology

Background:

• Norovirus P particles (PPs) are promising vaccine platforms due to their antigen presentation capabilities.
• Current chimeric PP vaccine production methods alter the original PP sequence and lack strategies for multi-loop antigen insertion.

Purpose of the Study:

• To develop a novel method for preparing distinct types of PP-based protein vaccines without altering the original PP sequence.
• To create chimeric PPs displaying Alzheimer's disease (AD) immunogens in specific loop configurations.

Main Methods:

• Site-directed mutagenesis introduced EagI and KpnI restriction sites into the P domain of Norovirus PPs.
• Synthesized genes encoding Aβ1-6 (Alzheimer's disease immunogen) were inserted into loop 2 (three copies) or all three loops (one copy each).
• Recombinant proteins were purified, and chimeric PPs were analyzed for particle formation, size, and morphology using TEM.

Main Results:

• Two distinct chimeric PPs, PP-3 copy-Aβ1-6-loop2 and PP-1 copy-Aβ1-6-loop123, were successfully purified.
• Chimeric PPs maintained their ability to form 24-mer nanoparticles, confirmed by particle size analysis and TEM.
• Both chimeric PP-based AD vaccines elicited potent immune responses in a mouse model.

Conclusions:

• A novel method for preparing Norovirus P particle-based vaccines has been successfully established.
• This method allows for the insertion of foreign antigens without affecting the PP sequence or nanoparticle formation.
• The developed chimeric PPs serve as effective vaccine candidates, demonstrating strong immunogenicity.