Studies on lipopolysaccharides of Proteus
The polysaccharide moieties of the lipopolysaccharides of serotyped strains of Proteus have been examined. The strains were selected to provide a wide range of serotypes. The primary acetic acid extracts of different strains of Proteus were fractionated on Sephadex G-50 and yielded three main components: a peak (I), which was composed mainly of polysaccharide; a second peak (II), the core polysaccharide, which contained heptose and phosphate; and a third component (III), which corresponded to a low molecular weight fraction and contained KDO and phosphate as well as other components. Peak I was not encountered in rough strains of Proteus. The chemical composition of the peaks obtained for S, SR, and R strains is discussed in relation to their agglutinating ability to homologous antiserum.