Immunochemical studies of Salmonella Dakar and Salmonella Telaviv O-antigens (serogroup O:28)

Abstract

Salmonella Dakar and Salmonella Telaviv bacteria belong to serogroup O:28, which represents 107 serovars and possesses only the epitope O28. Salmonella Telaviv has the subfactors O28(1) and O28(2) , whereas S. Dakar has O28(1) and O28(3) . So far, only limited serological and immunological information for this serogroup is available in the literature. Knowledge of the structures of their O-polysaccharides and the immunochemical investigations performed in this work allowed to reveal the nature of subfactor O28(1) as attributed to the presence of 3-linked (or 3,4-disubstituted) α-d-GalpNAc in the main chains of S. Dakar and S. Telaviv O-polysaccharides. An explanation for the cross-reactions between Salmonella enterica O28 O-antigens and other Salmonella O-polysaccharides and their structural similarity to Escherichia coli O-serogroups is also given.