Lipopolysaccharide-derived serotype polysaccharides from Neisseria meningitidis group B.

Three immunologically distinct types of polysaccharides have been isolated by diethylaminoethyl (DEAE) chromatography from the lipopolysaccharide extracts of group B Neisseria meningitidis. All types contain a set of common determinants, as well as distinct ones; all of these determinants are detectable by either immunodiffusion or enzyme-linked immunosorbent assay (ELISA). The polysaccharides elute from a Sepharose 4B column in the range of 2-3 x 10(5) daltons and have isoelectric points from 4.2 to 4.3. Their antigenicity is destroyed by oxidation but is unaffected by neuraminidase, lysozyme, or trypsin. One type of polysaccharide cross-reacts with the Gc2 polysaccharide of Neisseria gonorrhoeae in immunodiffusion systems. Chemical analysis indicates that these polysaccharides contain hexoses, hexosamines, 2-keto-3-deoxyoctonate, ethanolamine, and heptose; analysis of amino acids indicates protein contents of less than 0.05%. In contrast to the lipopolysaccharide from which they are derived, these polysaccharides contain no lipid A and less than 0.5% fatty acids. All three types are precipitated by wheat germ agglutinin but not by concanavalin A or fucose-binding protein. Specific inhibition of this precipitation can be achieved with N-acetyl glucosamine. These antigens may be the bases of a lipopolysaccharide-derived typing system for group B N. meningitidis.