Single-dose mucosal immunization with biodegradable microparticles containing a Schistosoma mansoni antigen

Area of Science:

• Immunology
• Vaccine Development
• Biomaterials Science

Background:

• Schistosoma mansoni infection remains a significant global health concern.
• Developing effective vaccines against schistosomiasis is a priority.
• Recombinant 28-kDa glutathione S-transferase (rSm28GST) is a key antigen for schistosomiasis vaccines.

Purpose of the Study:

• To evaluate the immunogenicity of rSm28GST delivered via biodegradable microparticles.
• To compare nasal versus oral administration routes.
• To assess the impact of different polymer types (PLG and PCL) on immune response.

Main Methods:

• Single nasal or oral administration of rSm28GST encapsulated in poly(lactide-co-glycolide) (PLG) or polycaprolactone (PCL) microparticles.
• Measurement of antigen-specific serum antibody responses (isotype profiling).
• Assessment of antibody neutralization of rSm28GST enzymatic activity.

Main Results:

• A single dose of 100 µg entrapped rSm28GST induced a stable, long-lasting antibody response peaking at 9-10 weeks, regardless of polymer or route.
• Immunoglobulin G1 (IgG1) was the predominant antibody isotype.
• Sera from mice receiving PLG microparticles (nasal/oral) effectively neutralized rSm28GST activity, unlike PCL or free antigen.

Conclusions:

• Single administration of PLG or PCL microparticles with rSm28GST elicits a strong, antigen-specific immune response.
• PLG microparticles administered nasally or orally demonstrated superior neutralization capacity.
• Microparticle-based delivery systems offer a promising strategy for developing effective schistosomiasis vaccines with controlled antigen release.