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Capsular Serotyping of Streptococcus pneumoniae Using the Quellung Reaction
Published on: February 24, 2014
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Partial depolymerization of capsular polysaccharides isolated from Streptococcus pneumoniae serotype 2 by various
Walmik Karbhari Gaikwad1, Swapan K Jana2, Rajeev M Dhere2
1Department of Technology, Savitribai Phule Pune University, Pune, 411007, India; Research and Development Department, Serum Institute of India Pvt. Ltd., Hadapsar, Pune, 411028, Maharashtra, India.
Carbohydrate Research
|January 27, 2022
Summary
Trifluoroacetic acid effectively depolymerizes bacterial capsular polysaccharides (CPS) and removes impurities while preserving antigenicity. This chemical method is superior for vaccine preparation compared to thermal or microwave treatments.
Area of Science:
- Biochemistry and Molecular Biology
- Vaccine Development and Immunology
Background:
- Partial depolymerization of bacterial capsular polysaccharides (CPS) is crucial for creating effective antigenic preparations for vaccines.
- Selecting an appropriate depolymerization method requires careful consideration of robustness, reproducibility, yield, and bioactivity retention.
Purpose of the Study:
- To evaluate various partial depolymerization methods for Streptococcus pneumoniae serotype 2 purified CPS.
- To identify a method that efficiently depolymerizes CPS, removes impurities, and retains antigenicity for vaccine applications.
Main Methods:
- Partial depolymerization of CPS using acid hydrolysis (trifluoroacetic acid), microfluidization, ultrasonication, thermal, and microwave methods.
- Evaluation of depolymerization by size exclusion high-performance liquid chromatography (SE-HPLC).
- Assessment of structural identity using 1H NMR spectroscopy and antigenicity via bead-based competitive inhibition assays.
Main Results:
- Microwave and thermal methods depolymerized CPS and reduced cell wall polysaccharide (CWPS) impurity but negatively impacted antigenicity.
- Trifluoroacetic acid treatment achieved CPS depolymerization and complete CWPS removal.
- The trifluoroacetic acid method retained 92 ± 4% of CPS antigenicity, outperforming other methods.
Conclusions:
- Trifluoroacetic acid hydrolysis is a highly advantageous method for partial CPS depolymerization in vaccine preparation.
- This method effectively removes CWPS impurities while maintaining significant CPS antigenicity, crucial for vaccine efficacy.
