Individual polysaccharide quantification in polyvalent pneumococcal conjugate vaccine using rate nephelometry

Area of Science:

• Vaccinology
• Analytical Chemistry
• Biotechnology

Background:

• Multivalent pneumococcal conjugate vaccines (PCV) require precise quality control for individual serotype polysaccharide content.
• Current methods using native polysaccharide (NP) as a reference standard may be unsuitable due to the conjugated nature of polysaccharides in the vaccine.

Purpose of the Study:

• To evaluate activated quenched polysaccharide (AQP) as a novel reference standard for quantifying individual serotype polysaccharides in multivalent PCV.
• To determine if AQP provides a more accurate and precise assay compared to NP.

Main Methods:

• Rate nephelometry assay utilizing serotype-specific antibodies.
• Comparison of AQP and NP as reference standards for quantifying polysaccharides in the formulated vaccine (drug product, DP).

Main Results:

• Activated quenched polysaccharide (AQP) closely mimics the epitope structure of the polysaccharide-protein conjugate after digestion.
• AQP demonstrated suitability as a reference standard for accurate and precise determination of individual polysaccharides in multivalent DP.

Conclusions:

• AQP is a more appropriate reference standard for rate nephelometry assays in PCV quality control.
• This method can be applied for drug product release, stability monitoring, and shelf-life determination.
• The strategy is adaptable for other polysaccharide-protein conjugate vaccines.