A number of bacterial
glycans are specific markers for the detection and the serological identification of microorganisms and are also widely used as antigenic components of
vaccines. The use of
gold nanoparticles as carriers for glyco-
epitopes is becoming an important alternative to the traditional conjugation with
proteins and synthetic
polymers. In this study, we aimed to prepare and evaluate in vivo glyco-
gold nanoparticles (glyco-GNPs) bearing the terminal-branched hexaarabinofuranoside fragment (Ara6) of
arabinan domains of
lipoarabinomannan and
arabinogalactan, which are principal
polysaccharides of the cell wall of Mycobacterium tuberculosis, the causative agent of
tuberculosis. In particular, we were interested whether the
antibodies generated against Ara6-GNPs would recognize the natural saccharides on the cell surface of different mycobacterial strains. Two synthetic Ara6
glycosides with amino-functionalized spacer aglycons differing in length and hydrophilicity were directly conjugated with spherical
gold nanoparticles (d = 15 nm) to give two sets of glyco-GNPs, which were used for the immunization of rabbits. Dot assays revealed cross-reactions between the two obtained
antisera with the hexaarabinofuranoside and the 2-aminoethyl aglycon used for the preparation of glyco-GNPs. Both
antisera contained high titers of
antibodies specific for Mycobacteria as shown by
enzyme-linked
immunosorbent assay using M. bovis and M. smegmatis cells as
antigens while there was only a weak response to M. phlei cells and no interaction with E. coli cells. The results obtained suggest that glyco-GNPs are promising agents for the generation of anti-mycobacterial
antibodies.