The chemical composition and serological reactions of lipopolysaccharides from serogroups A, B, X, and Y Neisseria meningitidis. Can. J. Biochem. 51, 1347Biochem. 51, -1354Biochem. 51, ( 1973.Analyses of the cell wall lipopolysaccharides prepared from Neisseria meningitidis serogroups A, B, X, and Y, indicated that they all contained glucose, galactose, glucosamine, heptose, lipid A, ethanolamine, fatty acids, phosphate, and protein. &me minor compositional differences in the sugar components did occur in that sialic acid (6-7%) was found only in serogroups B and Y, and galactosamine (2-3% ) in serogroups B and X. The individual fatty acid and amino acid compnents in the four wrogroups were also qualitatively similar. The Neisseria lipopalysaccharides studied have the same components as the core structure of the Enterobacterioceae but appear to lack the characteristic components of their 0-antigen side chains. Serological studies indicated that the lipopolysaccharides were homogeneous and were for the main part group specific in nature, despite their compositional similarity. On the basis of compositional differences alone it is not possible to account for the group specificity that they exhibit. JENNINGS, H. J., HAWES, C. El., ADAMS, G. A., et KENNY, C. P. The chemical composition and serologicaI reactions of lipopolysaccharides from serogroups A, B, X, and Y Neisseria meningitidis. Can. J . Biochem. 51, 1347-1354 (1973).k s analyses de lipopolysaecharides de la paroi cellulaire extraits des groups skriques A, B, X et Y de Nebseria meningitidis indiquent qu9ils contiennent tous les eonstituants suivants: glucose, .galactose, glucosamine, heptose, lipide A, tthanolamine, acides gras, phosphate et protkine. Quelques difftrences mineures peuvent se produire dans la composition glucidique: l'acide sialique ( 6 7 % ) n'est prksent que dans les groupes skriques B et Y et la galactosamine (2-3 % ) que dans les groups skriques B et X. Les acides gras et les acides amints individuels des quatre groups shriques sont qualitativement semblables. Chez Neisseria les lipopolysaccharides Ctudiks possuent les m h e s constituants que la structure principak des Enterobscterioceae mais les constituants caractkristiques des chaines latkrales de leur antighe 0 y sont absents. Las ktudes skrologiques montrent que les lipopolysaccharides sont homoghnes et que la plupart jouissent d'une sp6cificitk de groupe naturelle en cltpit des ressemblances de composition. Si on se base sur les seules difftrences de composition, il est impossible d'expliquer wtte sficificitk de groupe qu'ils exhibent.pracluit par le journal]