Convergent Synthesis of Oligosaccharides Structurally Related to Galactan I and Galactan II of Klebsiella Pneumoniae and their Use in Screening of Antibody Specificity

Abstract

Klebsiella pneumoniae Is a Gram-negative pathogenic bacterium that emerges a challenge for modern medicine due to intensively rising multi-drug resistance. Specific LPS O-chains represent promising targets for development of vaccines for immunoprophylaxis or immunotherapy of K. pneumoniae-caused diseases. Herein, the synthesis of di-, tetra-, and hexasaccharides which represent structural fragments of both galactan I and galactan II of K. pneumoniae LPS O-chains is described. The galactofuranoside building block used for assembling the galactan I chains was prepared by pyranoside-into-furanoside (PIF) rearrangement of the corresponding galactopyranoside precursor bearing an acid-labile temporary p-methoxybenzyl protecting group at O(3). The synthesized set of K. pneumoniae antigenic oligosaccharides in the form of their biotinylated derivatives was used to create a glycoarray which was applied for the screening of antibodies to galactan I and galactan II in anti-K. pneumoniae sera. The obtained results demonstrate the applicability of such a glycoarray-based assay for typing antibodies to Klebsiella strains belonging to most frequent O1 serogroup.