Immunochemical Studies of Polysaccharide Antigens of Escherichia coli 0100:K?(B):H2

Abstract

From E . coli 0100 :K ? (B) : H2 a lipopolysaccharide and an acidic polysaccharide were extracted with saline. The lipopolysaccharide was purifled by repeated ultracentrifugation and the acidic polysaccharide by fractional precipitation with cetavlon. Both substances contained rhamnose, galactose, glucosamine, glycerol, and phosphate.The lipopolysaccharide was degraded in lolo acetic acid at 100" and the degraded polysaccharide was fractionated on Sephadex 6-50. Thus a fraction was obtained which represents the specific polysaccharide moiety of the lipopolysaccharide. Comparison of this fraction with the acidic polysaccharide (chemical analysis, periodate oxidation, alkaline hydrolysis, partial acid hydrolysis) showed that both substances have not only the same composition (rhamnose, galactose, glucosamine, glycerol and phosphate in the molar ratios of 2 : I : 1 : 1 : 1) but also the same structure. Both substances consist of a main chain (composed of rhamnose, galactose and glucosamine) to which glycerol is bound via a phosphodiester bridge from one of its primary hydroxyl groups to one of the rhamnose residues. Some alternatives for the structure are presented.I n serological tests (passive haemagglutination, bacterial agglutination, immune precipitation and inhibition of these) it was shown that acidic polysaccharide and lipopolysaccharide have identical reactivities in anti-0 and anti-OK antisera. This confirms the structural identity of the polysaccharides. Cells from freshly isolated E . coli cultures are often not agglutinated by homologous 0 antibody. This 0 inagglutinability can be overcome by preheating the bacteria prior to the serological test. The relative ease with which this inhibitory capacity can be overcome is one of the parameters by which the K antigens of E . coli traditionally have been subdivided into the types A, B, and L. The K antigens of the B type loose their ability to inhibit 0 agglutination when the bacteria are heated a t 100" for 1 hour. However their agglutinin binding capacity is unimpaired [3], a fact which indicates that B antigens are neither destroyed upon heating nor that their serological specificity is lost.

Heterogeneity of Lipopolysaccharides. Analysis of Polysaccharide Chain Lengths by Sodium Dodecylsulfate‐Polyacrylamide Gel Electrophoresis

“…Degradation was performed in 1 % acetic acid at 100 "C for 1 -1.5 h. After removal of lipid A by centrifugation, the supernatant was lyophilized and the material obtained was frqctionated on Sephadex G50, as described previously [2,3].…”

Comparative Immunochemical Studies of the Surface Antigens of Escherichia coli Strains O8:K87(B?):H19 and (O32):K87(B?):H45

“…It was of interest to learn whether the (032)-specific lipopolysaccharide (or rather its 0-specific polysaccharide moiety, see [4]) and the K87-specific acidic polysaccharides had identical serological specificities. Therefore, bacterial agglutinations in absorbed antisera, passive haemagglutinations and their inhibitions as well as immune precipitations and their inhibitions in (032) and K87 systems were studied.…”

The structure of the O‐specific polysaccharide of Citrobacter O16 containing glycerol phosphate

“…these antigens represent teichoic-acid-like polymers. In the 0-antigen of Escherichia coli 0100 an unsubstituted glycerol residue is attached to the phosphate group [31], but the complete structure of this Table 2. Chemical shifts in the I3C-NMR spectrum of oligoside 3.…”