Santostefano Giovanni

Contacts:

giovanni.santostefano@phd.unipi.it

Supervisor(s):

Professor Valeria di Bussolo and Riccardo De Ricco

PhD project Title:

Discovery of alternative techniques for quantification and characterization of oligosaccharides

Abstract of the PhD project:

In the last decades, glyco-immunology has become an emerging field in the vaccine research and not only. Glyco-immunology provides insight on specific interactions of carbohydrates antigens with the immune system, that are commonly used as target for candidate vaccines. The oligo- and polysaccharides that cover the cell surface of bacterial pathogens are in fact crucial virulence factors being capable to interact with the immune system inducing the production of carbohydrate specific antibodies. Thus, they represent an attractive target for vaccine design, especially for glycoconjugate vaccines that are based on the chemical linkage between a carbohydrate antigen and a carrier protein. To certify a certain standard of quality and reproducibility in their production, it is critical to develop accurate and precise analytical tools to characterize them. However, carbohydrate compounds characterization at analytical level can be very challenging due to their intrinsic complexity, subtle differences based on stereochemistry, and lack of chromophores for detection. The project is aimed to disrupt the classical way of quantifying and characterize polysaccharide based bacterial vaccines. Currently, the most reported technology in literature to assess potency on glycoconjugates vaccines is the HPAEC-PAD (Anion Exchange Chromatography coupled with pulsed amperometric detector). Although the high sensitivity and selectivity of the technique, many pre-treatment steps are usually required (purification / hydrolysis) impacting the analysis lead time. Nowadays new analytical technologies are available that, combined with chemometric digital evaluation, may lead to the development of new ground-breaking analytical assays. So far, the exploration of alternative technologies in literature is very limited, therefore the project has the aim to provide new insights in the field of PS based bacterial vaccines control, also exploiting well stereo-defined synthetic oligosaccharides for the development of the methods.

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