Edwards N J, Monteiro M A, Faller G, Walsh E J, Moran A P, Roberts I S, High N J
1800 Stopford Building, School of Biological Sciences, The University of Manchester, University Road, Manchester M13 9PT, UK.
Mol Microbiol. 2000 Mar;35(6):1530-9. doi: 10.1046/j.1365-2958.2000.01823.x.
Helicobacter pylori NCTC11637 expresses a lipopolysaccharide (LPS) that comprises an O antigen side-chain with structural homology to the human blood group antigen Lewis X (Le(x)). The role of this molecule in adhesion of H. pylori to gastric epithelial cells was investigated. Mutants expressing truncated LPS structures were generated through insertional mutagenesis of rfbM and galE; genes encode GDP mannose pyrophosphorylase and galactose epimerase respectively. Compositional and structural analysis revealed that the galE mutant expressed a rough LPS that lacked an O antigen side-chain. In contrast, an O antigen side-chain was still synthesized by the rfbM mutant, but it lacked fucose and no longer reacted with anti-Le(x) monoclonal antibodies (Mabs). The ability of these mutants to bind to paraffin-embedded sections from the antrum region of a human stomach was assessed. Adhesion of the wild type was characterized by tropic binding to the apical surface of mucosal epithelial cells and cells lining gastric pits. In contrast, both the rfbM and galE mutants failed to demonstrate tropic binding and adhered to the tissue surface in a haphazard manner. These results indicate that LPS and, more specifically, Le(x) structures in the O antigen side-chain play an important role in targeting H. pylori to specific cell lineages within the gastric mucosa. The role of Le(x) in this interaction was confirmed by the tropic binding of synthetic Le(x), conjugated to latex beads, to gastric tissue. The observed pattern of adhesion was indistinguishable from that of wild-type H. pylori.
幽门螺杆菌NCTC11637表达一种脂多糖（LPS），其包含与人类血型抗原Lewis X（Le(x)）具有结构同源性的O抗原侧链。研究了该分子在幽门螺杆菌粘附胃上皮细胞中的作用。通过对rfbM和galE进行插入诱变产生了表达截短LPS结构的突变体；这些基因分别编码GDP甘露糖焦磷酸化酶和半乳糖差向异构酶。组成和结构分析表明，galE突变体表达一种缺乏O抗原侧链的粗糙LPS。相比之下，rfbM突变体仍能合成O抗原侧链，但缺乏岩藻糖，且不再与抗Le(x)单克隆抗体（Mabs）反应。评估了这些突变体与人胃窦区域石蜡包埋切片结合的能力。野生型的粘附特征是向性结合至粘膜上皮细胞和胃小凹内衬细胞的顶端表面。相比之下，rfbM和galE突变体均未能表现出向性结合，而是以随机方式粘附于组织表面。这些结果表明，LPS，更具体地说，O抗原侧链中的Le(x)结构在将幽门螺杆菌靶向胃粘膜内特定细胞谱系中起重要作用。与乳胶珠偶联的合成Le(x)与胃组织的向性结合证实了Le(x)在这种相互作用中的作用。观察到的粘附模式与野生型幽门螺杆菌的粘附模式无明显差异。
