Bacterial lipopolysaccharides

Abstract

Lipopolysaccharides are the 0-antigens and the endotoxins of Gram- negative bacteria. They are localized in the outer membrane of the bacterial cell wall and play an important role in the pathogenicity of bacterial infections, as well as in interaction with the host and its defense system. Lipopolysaccharides share a common architecture. They are built by a hydrophilic polysaccharide region which shows high structural variability and by a much less variable hydrophobic lipid moiety, termed lipid A, which anchors the molecule in the outer membrane of the cell wall. Lipid A is responsible for the pathophysiological properties of the so-called endotoxins. Recent work has shown that a number of non-toxic and structurally deviating lipid A types occur in non-enteric bacteria and their structural or compositional pecularities were shown to be correlated in many instances with the phylogenetic position of the respective species, as evidenced by I6S rRNA homologies. © 1989 IUPAC.