Molecular mechanisms and implications for infection of lipopolysaccharide variation in Neisseria.

The lipopolysaccharides of the pathogenic Neisseria species are subject to structural variation owing to a combination of intrinsic changes in lipopolysaccharide (LPS) biosynthesis and external modification of the LPS molecule with sialic acid. This variation appears to control bacterial behaviour by altering their ability to interact with human cells and to evade host immune defences. This interconversion of LPS phenotypes, which is also observed during the natural infection, is probably due to environmental regulation of LPS biosynthesis superimposed on spontaneous changes in the DNA of distinct LPS loci. LPS variation may be a common strategy of mucosal pathogens to colonize and persist within the human host.