E. Torre

F. Compostella

F. Faroldi

F. Sansone

L. Morelli

M. Giuliani

S. Fallarini

English

AIR Universita degli studi di Milano

ID: 21334
GLYCOCALIXARENES DECORATED WITH STREPTOCOCCUS PNEUMONIAE 19F CAPSULAR
POLYSACCHARIDE FRAGMENTS BIND TO ANTI-19F ANTIBODIES
F. Faroldi 1, L. Morelli 2, M. Giuliani 1, E. Torre 3, S. Fallarini 3, F. Sansone 1, F. Compostella 2
1Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma
2Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan
3Department of Pharmaceutical Sciences, University of “Piemonte Orientale”, Novara
Capsular polysaccharides (CPS) of encapsulated bacteria have been recognized as critical determinants
of bacterial virulence and found to be able to stimulate protective immunity against infection disease,
laying the bases for the development of current antibacterial vaccines. CPSs are cell-surface polymers
consisting of oligosaccharide repeating units. High molecular mass repetitive polysaccharide structures
are able to display simultaneously a greater number of densely displayed epitopes capable to effectively
interact in a clustered form with specific antibodies. The study of the chemical determinants necessary for
an effective interaction still requires detailed molecular insights. Nanomaterials or multivalent scaffolds
loaded with carbohydrate antigens allow repetitive antigen display, and are emerging as promising
synthetic vaccine candidates, alternative to classic polysaccharide/protein conjugate vaccines. In this
framework, we have decided to explore the potential of calixarenes as scaffolds for the multipresentation
of bacterial CPS fragments related to Streptococcus pneumoniae serotype 19F (SP19F). The hypothesis
was to assess if such scaffolds, presenting a limited number of copies of short SP19F fragments, displayed
in a multivalent form, are able to gain affinities and potencies towards the natural antibodies similar
to those observed for the natural polysaccharide. Herein, we will report the preparation and biological
evaluation of a family of calixarenes functionalized with saccharide fragments related to the trisaccharide
repeating unit of SP19F. In particular, a calix[6]arene, functionalized with six copies of the trisaccharide
repeating unit of SP19F, resulted very effective in competing with natural 19F polysaccharide in the
binding to specific anti-19F antibody. This compound shows efficacies and affinities higher than those
exhibited by the single trisaccharide, thus evidencing the effect of multivalency in increasing the ability of
the single saccharide unit to compete with natural 19F polysaccharide in the binding to specific anti-19F
antibody.


Glycocalixarenes decorated with Streptococcus pneumoniae 19F capsular polysaccharide fragments bind to anti-19F antibodies

https://air.unimi.it/retrieve/handle/2434/690423/1349042/ID21334_Abstract%20preview_calix.pdf

Glycocalixarenes decorated with Streptococcus pneumoniae 19F capsular polysaccharide fragments bind to anti-19F antibodies

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