# Poly-β-D-(1,6)-N-acetyl-glucosamine (PNAG) glycan vaccines with broad spectrum neutralizing activities

## TL;DR

Researchers developed a new method to create PNAG glycans with controlled acetylation, which could serve as a broad-spectrum vaccine against common hospital pathogens.

## Contribution

The study introduces an n+2 glycosylation strategy to synthesize PNAG glycans with controlled acetylation for vaccine development.

## Key findings

- Glycan microarray analysis identified DP8 and DP12 dPNAG glycans as optimal for antibody production.
- Antibodies against dPNAG DP8 with 40% acetylation showed best opsonic activity against three pathogens.
- The dPNAG DP8 conjugate provided highest protection in mice against Staphylococcus aureus.

## Abstract

The development of bacterial vaccines is a complex challenge due to the substantial serological diversity of protective antigens. One promising antigenic target is the conserved surface polysaccharide poly-β-(1,6)-N-acetyl-D-glucosamine (PNAG). Despite its widespread distribution, antibodies raised against PNAG have shown restricted efficacy in promoting microbial elimination in vitro and safeguarding against infections in vivo. Systematic studies and vaccine development have been hindered by limited knowledge of optimal antigenic features, such as chain length and degree of N-acetylation. Here, we describe an effective n + 2 glycosylation strategy enabling controlled synthesis of partially (dPNAG) and fully deacetylated PNAG glycans. Glycan microarray analysis shows that dPNAG glycans with DP8 and DP12 are optimal, with corresponding protein conjugates eliciting the highest IgG titers. Sera containing antibodies against the dPNAG DP8 conjugate with 40% acetylation exhibit the best opsonic activity against three prevalent nosocomial pathogens and confer the highest protection in female BALB/c mice against Staphylococcus aureus, supporting its potential as a vaccine candidate.

The conserved surface polysaccharide poly-β-(1,6)-N-acetyl-D-glucosamine (PNAG) is a promising vaccine target but antibodies raised against PNAG have shown restricted efficacy. Here, the authors describe an effective n + 2 glycosylation strategy, with control over the degree of N-acetylation, that allows the iterative assembly of partially and fully deacetylated PNAG glycans and investigate their potential as vaccine candidates.