Characterization and optimization of the glucan particle-based vaccine platform

Area of Science:

• Biotechnology
• Immunology
• Vaccine Development

Background:

• Glucan particles (GPs), derived from Saccharomyces cerevisiae cell walls, are primarily β-1,3-d-glucans.
• Previous research established GPs as a viable vaccine platform.

Purpose of the Study:

• To characterize CD4(+) T-cell and antibody responses to antigen-encapsulated GPs.
• To evaluate the impact of antigen dose, particle number, and formulation on immune stimulation.
• To assess the durability of immune responses elicited by the GP vaccine platform.

Main Methods:

• Ovalbumin (OVA) was either admixed with GPs or encapsulated within them.
• Immunizations were performed in mice with varying antigen doses, GP numbers, and schedules.
• T-cell responses (IFN-γ, IL-17A) and antibody isotypes (IgG1, IgG2c) were measured.
• Antigen trapping methods using GRAS materials were investigated.

Main Results:

• Encapsulating antigens in GPs, rather than admixing, enhanced CD4(+) T-cell and IgG2c antibody responses.
• Robust immunity was achieved with submicrogram antigen doses when GP numbers were maintained at 5 × 10(7).
• A single prime and boost immunization schedule elicited strong, long-lasting immune responses (up to 20 months).
• GRAS materials like alginate and calcium effectively trapped antigens within GPs, yielding robust immune responses.

Conclusions:

• Antigen-encapsulated GPs act as both an adjuvant and a delivery system, stimulating potent immunity.
• The GP platform elicits strong, durable T-cell and antibody responses at low antigen doses.
• Translationally relevant formulations using GRAS materials demonstrate the platform's practical applicability.