The quantification of anionic capsular polysaccharides historically has been based on assays specific for a given repeating unit.  These assays are typically laborious, require large amounts of analyte, and are challenging to automate.  The proliferation of multivalent vaccines containing diverse capsular polysaccharides would benefit from a fast and straightforward assay for polysaccharide titer, which is independent of the specific repeating unit structure.In this presentation, we describe a novel and robust, high throughput, microtiter assay for the quantification of anionic capsular polysaccharides.  The binding of a standard precipitant to anionic capsular polysaccharides results in a phase separation reaction wherein the suspension turbidity is proportional to polysaccharide titer.  The turbidity can be measured as absorbance across a range of wavelengths that resolve scattering light.  The applicability of this assay has been demonstrated successfully for polysaccharides of varying lengths and consisting of diverse repeating units.  A two-log dynamic range has been established with a mean relative standard deviation <10% across this range.  The assay has been qualified for use in samples as complex as fermentation broth by eliminating assay interferences from a variety of media components. Deployment of this new assay will greatly reduce the effort required to measure polysaccharide titer and yield during process development of such vaccines and increases throughput 30-fold with comparison to historical methods.

High throughput, turbidimetric assay for the quantification of capsular polysaccharides

245th National Meeting (2013)

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