LIPOPOLYSACCHARIDE-DERIVED SEROTYPE POLYSACCHARIDES FROM NEISSERIA-MENINGITIDIS GROUP-B

Three immunologically distinct types of polysaccharides have been isolated by di-ethylaminoethyl (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 × 105 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, hexo-samines, 2-keto-3-deoxyoctonate, ethanolamine, and heptose; analysis of amino acids indicates protein contents of <0.05%. In contrast to the lipopolysaccharide from which they are derived, these polysaccharides contain no lipid A and <0.5% fatty acids. All three types are precipitated by wheat germ agglutinin but not by concana-valin 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 lipopoly-saccharide-derived typing system for group B N. meningitidis. © 1979 by The University of Chicago.