Immunochemistry of K Antigens of Escherichia coli. 5. The K Antigen of E. coli 08:K 27 (A):H-

Abstract

An acidic polysaccharide which consists of D-glUCUroniC acid, D-glUCOSe, D-galaCtoSe and L-fucose in a molar ratio of 1 : 1 : 1 : 1 and which contains 5.2 o/o of 0-acetyl groups was isolated from Escherichia coli 08 : K 27 (A) : H-cells.About go0/, of the total polysaccharide present on the bacterial cell could not be extracted with saline at 60". This polysaccharide fraction was solubilized with 4501, aqueous phenol a t 65". Purification of the acidic polysaccharide was achieved with cetavlon precipitation. It was shown to be homogeneous by ultracentrifugation analysis. The acidic polysaccharide has a high molecular weight (mean value 3 x lo6), gives an aqueous solution with high viscosity ([q] = 5.0 dl/g) and possesses a very large form factor (/ifo = 6.5).Treatment of the acidic polysaccharide with dilute alkali produced smaller molecules of a molecular weight of about 100,000. Alkali treatment did not alter the sugar composition of the acidic polysaccharide nor did it impair its serological properties.The acidic polysaccharide was oxidized by sodium periodate with concomitant destruction of the galactose moiety. Glucuronic acid, glucose and fucose in the polysaccharide resisted periodate oxidation. When the periodate oxidized and sodium borohydride reduced polysaccharide was hydrolyzed, 0.8 moles of glycerol per mole of the oxidized galactose was detected in the hydrolyzate. The methylated acidic polysaccharide was subjected to methanolysis and the methyl glycosides of the methylated sugar constituents were investigated with the aid of gas liquid chromatography. Methyl-tetra-0-methyl-D-galactoside was found to be present in the methanolyzate.Acid hydrolysis of the acidic polysaccharide gave rise to the following charged oligosaccharides : (i) glucuronosyl-(1 : 3)-fucose, (ii) glucosyl-( 1 : 3)-glucuronosyl-( 1 : 3)-fucose and (iii) galactosyl-( 1 : 3)-glucosyl-( 1 : 3)-glucuronosyl-( 1 : 3)-fucose. No neutral oligosaccharides were detected in hydrolyzates of the acidic polysaccharide.It is concluded that the acidic polysaccharide of E. coli 08:K27(A):H-consists of subunits of a molecular weight of about 100,000. These subunits are probably linked through ester bonds between carboxyl groups of glucuronic acid and hydroxyl groups of sugar constituents. It is suggested that the polysaccharide chains of the subunits consist of glucose, glucuronic acid and fucose in repeating order to which galactose is bound in I : 3-linkage, with glucose as the branch The acidic polysaccharide absorbes directly onto erythrocytes. In passive haemagglutination tests the polysaccharide-sensitized red cells reacted strongly with E. coli 08:K27 anti OK and anti K sera but very weakly with anti 0 serum. After absorption of anti OK serum with the purified acidic polysaccharide the antiserum no longer agglutinated the encapsulated strain. The acidic polysaccharide was precipitated by 08:K27 antiserum and by K27 antiserum. This precipitation was inhibited by the tetrasaccharide (iii) and to a lesser extent by the trisaccharide (ii), but...

Immunochemistry of K Antigens of Escherichia coli. The K29 Antigen of E. coli 09:K29(A):H-

“…After treatment with alkali a homogeneous preparation was obtained. This had been observed in earlier studies and interpreted as due to interchain ester linkages [2,5,6]. …”

Immunochemistry of K Antigens of Escherichia coli

“…This characteristic has been observed with a series of A antigens [10, 21 and unpublished results] but never with B-or L-antigens of E. coli. It therefore seems to be characteristic for A antigens.…”

Genetic Determinants of the Synthesis of the Polysaccharide Capsular Antigen K27(A) of Escherichia coli

“…The K27 antigen is an acidic polysaccharide, the repeating units of which consist of glucose, galactose, fucose and glucuronic acid (Jann, Jann & Schneider, 1968). As shown above, two gene loci appear to participate in the synthesis of the K27 antigen of E. coN 0 8 : K27, one closely linked to his, the other to trp.…”