Characterisation of the Salmonella O:8 antigen in the O-chain of the lipopolysaccharide produced by Salmonella Virginia O:8

The antigenic O-polysaccharide of the lipopolysaccharide produced by Salmonella Virginia (O:8), analyzed by methylation, partial acid hydrolysis, and one- and two-dimensional nuclear magnetic resonance methods, was found to be a polymer of a repeating pentasaccharide unit composed of D-mannose, D-galactose, L-rhamnose, D-abequose, and O-acetyl (2:1:1:1:1.3) and having the following structure:[Formula: see text]The disaccharide structure α-D-Abep-(1 → 3)-L-Rhap was identified as the Salmonella O:8 antigenic factor epitope, since the removal of α-D-Abep residues from the O-polysaccharide left a residual tetrasaccharide repeating unit backbone that did not show reaction with Salmonella type O:8 factor antiserum.Key words: Salmonella, endotoxin, lipopolysaccharide, polysaccharide, nuclear magnetic resonance.