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Development of a novel competitive ELISA method for Typhoid Vi Polysaccharide Quantitation
Ashwani Kumar Mandyal1, Rajasekaran Angannan2, Balananda Dhurjati Kumar Putcha2
1Department of Biotechnology, Vignan's Foundation for Science, Technology and Research, Vadlamudi, Guntur District, Andhra Pradesh, 522213, India; R&D Department, Auro Vaccines Private Limited, Indrakaran, Sangareddy District, Hyderabad, Telangana, 502329, India.
A new competitive ELISA method accurately quantifies Vi polysaccharide (ViPS) in typhoid vaccines. This sensitive assay offers a reliable tool for vaccine quality control, complementing existing methods.
Area of Science:
- Vaccinology
- Analytical Chemistry
- Immunochemistry
Background:
- Licensed typhoid vaccines utilize Vi polysaccharide (ViPS), a Salmonella Typhi antigen, in various forms.
- Quantifying ViPS is challenging due to its poor adsorption in conventional ELISA formats, limiting sensitivity.
Purpose of the Study:
- To develop and evaluate a novel competitive enzyme-linked immunosorbent assay (c-ELISA) for sensitive ViPS quantitation.
- To assess the performance of the developed c-ELISA against established analytical methods.
Main Methods:
- A novel competitive ELISA (c-ELISA) was developed using biotinylated ViPS as a detector probe.
- The c-ELISA performance was validated against the Hestrin assay and High Performance Anion Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD).
Main Results:
- The developed c-ELISA demonstrated comparable specificity, accuracy, and repeatability to HPAEC-PAD.
- c-ELISA exhibited higher sensitivity than HPAEC-PAD for unconjugated ViPS (free-PS) quantification (90-10,000 ng/ml).
Conclusions:
- The novel c-ELISA is a reliable and sensitive immunochemical method for ViPS quantification.
- This c-ELISA complements HPAEC-PAD, providing orthogonal analytical platforms for typhoid vaccine production and quality control.
