Synthesis of structure-defined β-1,4-GlcNAc-modified wall teichoic acids as potential vaccine against...

Area of Science:

• Microbiology and Immunology
• Vaccine Development
• Carbohydrate Chemistry

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant threat due to life-threatening infections and antibiotic resistance.
• Developing effective anti-MRSA vaccines is a critical strategy to combat the growing resistance crisis.
• Wall teichoic acids (WTAs) from S. aureus, particularly those glycosylated with β-1,4-GlcNAc, are identified as key antigens linked to β-lactam resistance.

Purpose of the Study:

• To synthesize structure-defined β-1,4-GlcNAc-modified WTAs with varying chain lengths and modification patterns.
• To evaluate the immunogenicity of these WTAs conjugated to tetanus toxin (TT) in a mouse model.
• To establish a structure-immunogenicity relationship for developing effective anti-MRSA vaccines.

Main Methods:

• Ionic liquid-supported oligosaccharide synthesis (ILSOS) strategy for efficient, chromatography-free synthesis of WTAs.
• Conjugation of synthesized WTAs with tetanus toxin (TT) to create vaccine candidates.
• In vivo immunological studies in a mouse model to assess T cell responses, antibody production, and functional activity.

Main Results:

• The synthesized WTAs-TT conjugates successfully elicited robust T cell-dependent immune responses and high levels of specific anti-WTAs IgG antibodies.
• Antibody production and immunogenicity were directly correlated with WTA structure, including chain length and the β-1,4-GlcNAc modification pattern.
• The heptamer WTA conjugate T6, featuring three β-1,4-GlcNAc modified RboP units, demonstrated the highest antibody titers, binding affinity, and potent opsonic killing activity against both MSSA and MRSA.

Conclusions:

• β-1,4-GlcNAc glycosylated WTAs are promising antigens for the development of novel anti-MRSA vaccines.
• The structure of WTAs, specifically chain length and GlcNAc modification, significantly influences immunogenicity and efficacy.
• The T6 conjugate represents a lead candidate for further development towards an effective MRSA therapeutic or prophylactic vaccine.