Evaluation of structural modification induced activation of pneumococcal polysaccharide by GC-MS for the conjugate vaccine

Polysaccharide (Ps) activation evaluation is an imperative quality attribute in a conjugate vaccine. Pneumococcal polysaccharide (PnPs) serotypes 5, 6B, 14, 19A and 23F were cyanylated for 3 and 8 min. The cyanylated and non-cyanylated polysaccharides were methanolysed and derivatized to assess the activation of each sugar by GCMS. The activation of 22 and 27% serotype 6B and 11 and 36% in serotype 23 F Ps at 3 and 8 min respectively showed controlled conjugation kinetics with CRM197 carrier protein estimated by SEC-HPLC and optimal absolute molar mass by SEC-MALS. The Glc and Gal are the most commonly activated sugars of all PnPs serotypes while N-acetyl sugars PneuNAc, GalNAc and Rha in serotypes 5, 14 and 19A respectively showed >50% activation which contributes to conjugate aggregate formation at 8 min compared to 3 min cyanylation. The GC-MS analysis of structural modifications at functional groups entails important information to characterize the activated polysaccharide for consistent conjugate vaccine manufacturing.

Automated summary

Polysaccharide activation evaluation is crucial for conjugate vaccine quality. Pneumococcal polysaccharides of serotypes 5, 6B, 14, 19A, and 23F were cyanylated for 3 and 8 minutes, and their activation was assessed through methanolysis and derivatization. The results showed controlled conjugation kinetics in serotype 6B (22% and 27%) and serotype 23F Ps (11% and 36%) at 3 and 8 minutes, respectively. The GC-MS analysis of structural modifications provides important information for consistent conjugate vaccine manufacturing.