Yamaoka Y, El-Zimaity H M, Gutierrez O, Figura N, Kim J G, Kodama T, Kashima K, Graham D Y
VA Medical Center and Baylor College of Medicine, Houston, Texas, USA.
Gastroenterology. 1999 Aug;117(2):342-9. doi: 10.1053/gast.1999.0029900342.
BACKGROUND & AIMS: The variation in size of Helicobacter pylori CagA is related to repeat sequences in the 3' region of the cagA gene. We investigated whether structural subtypes of the cagA 3' region are associated with presentation of the infection or to susceptibility to acid.
We examined 319 cagA-positive H. pylori isolates: 84 isolates from Bogota, Colombia; 83 from Houston, Texas; 24 from Siena, Italy; and 128 from Seoul, Korea. The cagA 3' region was amplified by polymerase chain reaction. Gastric histology and susceptibility to pH 3 were evaluated in relation to the number of cagA repeat regions.
Strains with more than three repeat regions were associated with significantly higher scores for gastric mucosal atrophy and intestinal metaplasia than those with fewer repeat regions. H. pylori strains with three repeat regions were also significantly more susceptible to pH 3 than isolates with fewer repeat regions.
H. pylori strains with more than three repeat regions in the 3' region of the cagA gene are associated with enhanced histological injury and with reduced survival in acidic conditions. It is hypothesized that these variants arise within the stomach.
幽门螺杆菌CagA大小的变化与cagA基因3'区域的重复序列有关。我们研究了cagA 3'区域的结构亚型是否与感染表现或酸敏感性相关。
我们检测了319株cagA阳性幽门螺杆菌分离株：84株来自哥伦比亚波哥大；83株来自得克萨斯州休斯顿；24株来自意大利锡耶纳；128株来自韩国首尔。通过聚合酶链反应扩增cagA 3'区域。根据cagA重复区域的数量评估胃组织学和对pH 3的敏感性。
与重复区域较少的菌株相比，重复区域超过三个的菌株胃黏膜萎缩和肠化生的评分显著更高。与重复区域较少的分离株相比，具有三个重复区域的幽门螺杆菌菌株对pH 3也明显更敏感。
cagA基因3'区域重复区域超过三个的幽门螺杆菌菌株与组织学损伤加重和在酸性条件下存活率降低有关。据推测，这些变体在胃内产生。
