Instituto de Patologia e Imunologia Molecular da Universidade do Porto, Porto, Portugal.
Braz J Med Biol Res. 2010 Jul;43(7):611-8. doi: 10.1590/s0100-879x2010007500049. Epub 2010 Jun 7.
Helicobacter pylori adhesion to gastric epithelial cells constitutes a key step in the establishment of a successful infection of the gastric mucosa. The high representation of outer membrane proteins in the bacterial genome suggests the relevance of those proteins in the establishment of profitable interactions with the host gastric cells. Gastric epithelial cells are protected by a mucous layer gel, mainly consisting of the MUC5AC and MUC6 mucins. In addition to this protective role, mucins harbor glycan-rich domains that constitute preferential binding sites of many pathogens. In this article we review the main players in the process of H. pylori adhesion to gastric epithelial cells, which contribute decisively to the high prevalence and chronicity of H. pylori infection. The BabA adhesin recognizes both H-type 1 and Lewis b blood-group antigens expressed on normal gastric mucosa of secretor individuals, contributing to the initial steps of infection. Upon colonization, persistent infection induces an inflammatory response with concomitant expression of sialylated antigens. The SabA adhesin mediates H. pylori binding to inflamed gastric mucosa by recognizing sialyl-Lewis a and sialyl-Lewis x antigens. The expression of the BabA and SabA adhesins is tightly regulated, permitting the bacteria to rapidly adapt to the changes of glycosylation of the host gastric mucosa that occur during infection, as well as to escape from the inflammatory response. The growing knowledge of the interactions between the bacterial adhesins and the host receptors will contribute to the design of alternative strategies for eradication of the infection.
幽门螺杆菌(Helicobacter pylori)黏附于胃上皮细胞,这是其成功感染胃黏膜的关键步骤。该细菌的基因组中大量存在的外膜蛋白提示这些蛋白在与宿主胃细胞建立互利关系中具有重要作用。胃上皮细胞受黏液层凝胶的保护,主要由 MUC5AC 和 MUC6 黏蛋白组成。除了具有保护作用外,黏蛋白还具有富含聚糖的结构域,是许多病原体的优先结合位点。本文综述了幽门螺杆菌黏附于胃上皮细胞的主要参与者,这些参与者对幽门螺杆菌的高流行率和慢性感染起着决定性作用。黏附素 BabA 可识别分泌型个体正常胃黏膜上表达的 H 型 1 型和 Lewis b 血型抗原,有助于感染的初始步骤。定植后,持续感染会引起炎症反应,同时伴有唾液酸化抗原的表达。黏附素 SabA 通过识别炎症胃黏膜上的唾液酸化 Lewis a 和唾液酸化 Lewis x 抗原,介导幽门螺杆菌的黏附。BabA 和 SabA 黏附素的表达受到严格调控,使细菌能够快速适应感染过程中宿主胃黏膜糖基化的变化,并逃避炎症反应。对细菌黏附素与宿主受体之间相互作用的深入了解,将有助于设计替代策略来根除感染。