A SURFACE POLYSACCHARIDE OF ESCHERICHIA-COLI O111 CONTAINS O-ANTIGEN AND INHIBITS AGGLUTINATION OF CELLS BY O-ANTISERUM
A SURFACE POLYSACCHARIDE OF ESCHERICHIA-COLI O111 CONTAINS O-ANTIGEN AND INHIBITS AGGLUTINATION OF CELLS BY O-ANTISERUM
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DOI：
10.1128/jb.151.3.1210-1221.1982
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发表时间：
1982-01-01
影响因子：
3.2
通讯作者：
LEIVE, L
中科院分区：
文献类型：
--
作者：
GOLDMAN, RC;WHITE, D;LEIVE, L
大肠杆菌 O111 的 O 抗原的重复五糖含有半乳糖、葡萄糖、N-乙酰氨基葡萄糖和结肠糖，后者代表主要的抗原决定簇。先前显示该菌株的苯酚提取物释放出含有O-抗原碳水化合物的两个级分（I和II），并且这两个级分被认为是脂多糖。我们现在已经表征了组分 I 和 II，并得出结论，只有组分 II 代表脂多糖。级分 II 含有磷酸盐、2-酮-3-脱氧辛酸、β-羟基肉豆蔻酸和有效的内毒素活性，而级分 I 缺乏脂质 A 和脂多糖核心寡糖区域的所有这些特性。级分 I 和 II 各占细胞 O 抗原总量的 50%，并且均存在于细胞表面。两种组分都是代谢稳定的，并且它们之间不存在前体-产物关系。级分 II 的数均分子量为 15,800，相当于每个分子平均有 12 个 O 抗原重复。相比之下，级分 I 的数均分子量为 354,000，相当于每个分子平均有 404 个 O 抗原重复。热处理前，大肠杆菌O111细胞与O-血清的凝集效果较差；尽管这表明存在胶囊，但从未检测到相应的 K 抗原。我们得出结论，当组分 I 存在于细胞表面时，会抑制 O 血清对未加热的大肠杆菌 O111 培养物的凝集，因为： (i) 缺乏组分 I 的变体菌株无需事先加热即可被 O 血清凝集； (ii)用纯化的级分I包被的红细胞表现得与含有级分I的细菌一样，表现出对O-血清凝集的抑制； (iii) 热处理释放组分 I 并使细菌细胞在 O 血清中凝集。
The repeating pentasaccharide of O-antigen from Escherichia coli O111 contains galactose, glucose, N-acetylglucosamine, and colitose, the latter representing the major antigenic determinant. Phenol extraction of this strain was previously shown to release two fractions (I and II) containing O-antigen carbohydrate, and both fractions were believed to be lipopolysaccharide. We have now characterized fractions I and II and conclude that only fraction II represents lipopolysaccharide. Fraction II contains phosphate, 2-keto-3-deoxyoctonate, beta-hydroxymyristic acid, and potent endotoxin activity, whereas fraction I was deficient in all of these properties of the lipid A and core oligosaccharide regions of lipopolysaccharide. Fractions I and II each represented 50% of the total cellular O-antigen, and both were present on the cell surface. Both fractions were metabolically stable, and no precursor-product relationship existed between them. Fraction II had a number-average molecular weight of 15,800, corresponding to an average of 12 O-antigen repeats per molecule. In contrast, fraction I had a number-average molecular weight of 354,000, corresponding to an average of 404 O-antigen repeats per molecule. Before heat treatment, cells of E. coli O111 are poorly agglutinated by O-serum; although this indicates the presence of a capsule, the corresponding K-antigen was never detected. We conclude that fraction I, when present on the cell surface, inhibits agglutination of unheated cultures of E. coli O111 by O-serum because: (i) a variant strain which lacks fraction I was agglutinated by O-serum without prior heating; (ii) erythrocytes coated with purified fraction I behaved like bacteria containing fraction I in showing inhibition of O-serum agglutination; and (iii) heat treatment released fraction I and rendered bacterial cells agglutinable in O-serum.