Specificity of rabbit antisera against the rough lipopolysaccharide of Salmonella minnesota strain R7 (chemotype Rd 1 P − )

Rabbit polyclonal antibodies against the lipopolysaccharide (LPS) of the Rd 1 P − mutant strain R7 of Salmonella minnesota were serologically characterized using R7 LPS, dephosphorylated LPS, deacylated LPS, deacylated, dephosphorylated and reduced LPS, and synthetic partial structures. The latter comprised partial structures of the core region of Rd 1 P − LPS bound to the β 1 → 6‐linked glucosamine disaccharide with two amide‐linked 3‐hydroxytetradecanoic acid residues or artificial glycoconjugates comprised of the synthetic oligosaccharides coupled to bovine serum albumin. Using a passive hemolysis and an enzyme immunoassay, absorption and inhibition experiments, the antibody specificities present could be determined. One group of antibodies required components of the core region and the phosphorylated glucosamine disaccharide of the lipid A moiety for binding. The majority of phosphate‐independent antibodies was directed against the trisaccharide l ‐glycero‐α‐ d ‐manno‐heptopyranose(1 → 3)‐ l ‐glycero‐α‐ d ‐manno‐heptopyranose(1 → 5)3‐deoxy‐ d ‐manno‐octulosonic acid. Antibodies against the 1 → 3‐ and 1 → 7‐linked heptose disaccharides and against a single heptose were also detected, however, with low titers. No antibodies were found which required the presence of fatty acids.