浙江地区幽门螺杆菌临床菌株空泡毒素基因的变异及其表达活性分析

目的 了解浙江地区消化性溃疡(PU)和慢性胃炎(CG)患者感染幽门螺杆菌(Hp)vacA基因的变异及其空泡毒素表达情况。方法 从70株Hp中选择部分菌株测定其vacA基因的s区和m区核苷酸序列。用细胞培养的方法检测Hp菌株的空泡毒性。结果 6株sla型Hp菌株的s区扩增产物与报道的sla型60190株核苷酸序列相似性为93．2％～98．3％，4株m2型Hp菌株的m区扩增产物与报道的m2型87—203株核苷酸序列之间相似性为93．8％～97．6％。1株m1b型Hp菌株的m区扩增产物与报道的m1型60190株相应序列相似性为87．3％，与m2型87—203株相应序列之间相似性为71．7％。所有5株sla／m1型Hp对HeLa、RK-13和SGC-7901三种细胞均有明显的空泡毒作用；仅27.9％(12／43)的sla／m2型菌株对HeLa细胞表现为空泡毒作用，但分别有65．1％(28／43)和62.8％(27／43)的菌株对RK-13细胞和SGC-7901细胞有空泡毒作用。所有sla／m1b和sla／m1b—m2型Hp菌株对三种细胞均有明显的空泡毒作用，以RK-13细胞计，81.0％(17／21)的sla／m1b型Hp菌株和1株sla／m1b—m2型有空泡毒性。PU组感染的Hp菌株空泡毒性(84．4％)强于CG组(60．5％)，差异有统计学意义(P＜0．05)。结论 浙江地区患者感染的Hp菌株vacA基因变异主要在于m区。vacA基因空泡毒性的表达在HeLa细胞中低毒性的sla／m2型菌株在RK-13和SGC-7901细胞中仍有较高的空泡毒性。m1b型Hp空泡毒性强度介于m1和m2型之间。PU患者感染的Hp菌株其空泡毒性明显强于CG组。

Analysis on the variance of vacA genotypes and their vacuolating toxin activity of Helicobacter pylori isolates in Zhejiang area

Objective To analyze the variance of vacA genotypes and their vacuolating toxin activity of Helicobacter pylori ( H.pylori ) isolates from patients with peptic ulcer(PU) or chronic gastritis(CG) in Zhejiang area. Methods Signal and middle regions of parts of seventy H.pylori strains were sequenced after T-A cloning. Vacuolating toxin activity was detected with cell culture method. Results Compared with the reported sequences of H.pylori strain 60190 with s1a/m1 genotype, similarities of the signal-region sequences from 6 s1a-type H.pylori isolates were found to be 93.2%- 98.3 %, and from 1 m1b-type strain was 87.3 %. When compared with the corresponding sequences of H.pylori strain 87-203 with m2 genotype, similarities of the mid-region from 4 m2-type isolates and 1 m1b-type isolates were 93.8%- 97.6 % and 71.7 %, respectively. All 5 strains with s1a/m1 type produced vacuolating toxin activity detected by HeLa, RK-13, and SGC-7901 cell lines. Only 12 strains with s1a/m2 type produced cytotoxin in HeLa cells but 65.1 %(28/43) and 62.8 %(27/43) strains had cytotoxin in RK-13 and SGC-7901 cells. In RK-13 cells, 81.0 %(17/21) strains with s1a/m1b produced vacuolating toxin activity. Conclusion Variance of vacA genotypes of local H.pylori isolates mainly lied in mid-region. H.pylori isolates with m2 type produced high cytotoxin in RK-13 and SGC-7901 cells, and low cytotoxin in HeLa cells. Cytotoxin strength of m1b-type strains was between strains with m1 and m2 types. Vacuolating toxin activity of strains from PU group seemed obviously higher than that from CG group.