Polymeric epitope-based vaccine induces protective immunity against group A Streptococcus

Area of Science:

• Vaccinology
• Biotechnology
• Microbiology

Background:

• Group A Streptococcus (Strep A) is a dangerous pathogen lacking a licensed vaccine.
• Current vaccine development faces challenges in efficacy and scalability.

Purpose of the Study:

• To develop a novel vaccine strategy using biopolymer particles (BPs) displaying Strep A peptides.
• To evaluate the immunogenicity, stability, and protective efficacy of the developed vaccine candidate.

Main Methods:

• Engineered endotoxin-free Escherichia coli to produce biopolymer particles displaying Strep A peptides (p*17 and K4S2).
• Characterized the morphology, size, and charge of the assembled BP-p*17-S2 particles.
• Assessed particle cytotoxicity, stability at ambient temperature, and immunogenicity in a mouse model.
• Evaluated protective immunity via intranasal challenge with Strep A.

Main Results:

• Successfully assembled BP-p*17-S2 particles with core-shell morphology.
• BP-p*17-S2 particles were stable at ambient temperature, non-cytotoxic, and elicited high antibody and cytokine titers in mice.
• Vaccinated mice showed significant reduction (>100-fold) in pathogen burden after Strep A challenge, indicating protective immunity.

Conclusions:

• The biopolymer particle approach is a cost-effective and scalable method for Strep A vaccine development.
• BP-p*17-S2 demonstrates promising immunogenic and protective properties, offering an attractive alternative to current strategies.