Study: New Vaccine Modality Using Biopolymer Particles Shows Promise in Group A Streptococcus

Investigators have developed a new vaccine modality, which is currently at the proof-of-concept stage and in early development, that shows promise treating group A Streptococcus (Strep A), according to the results of a study from Griffith University.¹

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Bernd Rehm, PhD, and Shuxiong Chen, PhD, from the Griffith Institute for Drug Discovery and Centre for Cell Factories and Biopolymers, tested the vaccine modality against a more established vaccine from Griffith for Strep A and is currently performing strongly in human trials in Canada.¹

"It's a synthetic vaccine based on our innovative technology that uses reprogrammed safe Escherichia coli cells to assemble vaccine particles at high yield," Rehm said in a statement. "To develop the vaccine, we reprogrammed bacterial cell factories to assemble biopolymer particles coated with the Griffith Strep A antigens and found the particles were safe and protected against infection.”¹

Investigators of the study used a biopolymer particle approach for Strep A vaccine candidate peptides p*17 derived from M protein and K4S2 derived from non-M protein. They gathered biopolymer particles that displayed both peptides densely (BP-p*17-S2) and assembled them in a single step, inside an engineered endotoxin-free Escherichia coli strain.BP-p*17-S2 was formulated with aluminum hydroxide as adjuvant.²

The study authors reported no cytotoxicity when tested against HEK-293 cells. The study on stability revealed that BP-p*17-S2 is ambient-stable temperature, according to the results.²

Additionally, investigators reported that mice showed no adverse reactions when immunized with the vaccine candidate. There were also high titers of peptide-specific antibodies and cytokines produced. The study authors stated that the immune response could be related to the protective immunity in animal models of infection, including mice with Strep A that had intranasal challenges. Investigators said that there was a significant reduction of greater than 100-fold of pathogen burden in the nose-associated lymphoid tissues, lung, and spleen.²

Rehm said that the results showed technology has helped the development of vaccines that are safe to use and induce strong immune responses against Strep A. According to Chen, this advancement could serve as a medical breakthrough for developing future vaccines.¹

"We developed a cost-effective manufacturing process, and the resulting vaccines are ambient-temperature stable, strongly facilitating stockpiling and dissemination in developing countries where refrigeration is not always available,” Rehm added in the statement.¹

The study authors said that the cost-effective manufacturing of the stable biopolymer particles coated with Strep A peptides could offer an alternative to current Strep A vaccine development. They added that the immunogenic properties are also promising.²

According to the investigators, Strep A leads to a wide range of illnesses, including mild pharyngitis and impetigo, as well as more invasive diseases, such as toxic shock syndrome, necrotizing fasciitis, and cellulitis.¹

One challenge with Strep A is mortality that is indirectly caused by the development of antimicrobial resistance, which results from the consumption of too many antibiotics.¹

The CDC has estimated that approximately 14,000 to 25,000 cases of Strep A occur in the United States each year, with 1500 to 2300 individuals dying due to the disease annually, with the most recent 5 years of data available.³

References

1. Scientists on the cusp of a new vaccine modality breakthrough. News release. ScienceDaily. August 24, 2023. Accessed August 28, 2023. https://www.sciencedaily.com/releases/2023/08/230824003813.htm
2. Chen S, Ozberk V, Sam G, Gonzaga ZJC, et al. Polymeric epitope-based vaccine induces protective immunity against group A Streptococcus. NPJ Vaccines. 2023;8(1):102. doi:10.1038/s41541-023-00695-x
3. Centers for Disease Control and Prevention. Group A Streptococcal (GAS) Disease. Updated June 27, 2023. Accessed August 28, 2023. cdc.gov/groupastrep/surveillance.html