Diversity of Helicobacter pylori isolates in expression of antigens and induction of antibodies

AIM： To obtain evidence for selection of antigens used in genetically engineered vaccine against Helicobacter pylori （H pylori）. METHODS： Enzyme linked immunoabsorbent assay （ELISA） was established on the basis of recombinant protein antigens rUreB, rHpaA, rVacA, rCagA1, rNapA, rFlaA and rFlaB of Hpylori to detect expression rates of the antigens in bacterial isolates as well as positive rates of the antibodies in sera from H pylori-infected patients. PCR was applied to the detection of carrying rates of the genes encoding antigens in the isolates. RESULTS： The outputs of rUreB, rHpaA, rVacA, rCagA1, rNapA, rFlaA and rFlaB were approximately 35%, 32%, 15%, 23%, 56%, 25% and 20% of the total bacterial proteins, respectively. One hundred and fifty-one strains of H pylori were isolated from 347 biopsy specimens of chronic gastritis, peptic ulcer or gastric adenocarcinoma, with a positive rate of 43.5%. All of the isolates expressed UreB, HpaA, FlaA and FlaB while 52.3%, 92.1% and 93.4% of the isolates expressed VacA, CagA and NapA, respectively. In the sera of 151 Hpylori-infected patients, the positive rates of IgG antibodies against UreB, HpaA, VacA, CagA, NapA, FlaA and FlaB were 100%, 87.4%, 43%, 71.5%, 89.4%, 84.8% and 79.5%, respectively. Furthermore, the expression frequencies of VacA and NapA were found to be relative to the severity of gastric diseases （P = 0.016 and P 〈 0.0001, respectively）. CONCLUSION： UreB antigen is the top option of developing genetically engineered vaccine against H pylori followed by NapA or HpaA.     

幽门螺杆菌vacA基因型及其表达产物与胃十二指肠疾病关系的研究

目的 探讨幽门螺杆菌ｖａｃＡ基因型及其表达产物－ＶａｃＡ与胃十二指肠疾病之间的关系。方法 用聚合酶链反应技术测定６２株从慢性胃炎,消化性溃疡和胃癌患者中分离获得的幽门螺杆菌（Ｈｐ）菌株的ｖａｃＡ基因型,用Ｈｅｌａ细胞测定Ｈｐ菌株体外ＶａｃＡ活性。     

中国上消化道疾病患者幽门螺杆菌感染根除前后胃粘膜病理改变与空泡毒素活性的关系

目的：观察幽门螺杆菌（H.pylori)阳性消化性溃疡病和慢性胃炎患者H.pylori根除前后胃粘膜病理改变与空泡毒素（VacA)活性的关系。方法：功能性消化不良伴H.pylori感染的中国患者74例,于H.pylori根除前和4－6周后作胃镜检查,根据新悉尼病理分级法按半定量记分对治疗前后的胃粘膜病理变化程度进行分级。结果：VacA^ 菌检出率为80％（59／74）,消化性溃疡病患者的检出率与慢性胃炎患者无明显差别;VacA^ 和VacA^-组患者的H.pylori根除率亦无明显差别。根除治疗前,VacA^ 和VacA^-组患者的胃粘膜慢性炎症、活动性、表面上皮损伤、萎缩、肠化和淋巴滤泡数量无显著差别;治疗后4－6周,两组患者的胃窦粘膜炎症活动性、表面上皮损伤和慢性炎症程度均明显减轻,尤以前者为著（P＜0．0001）,VacA^ 组患者的胃窦部淋巴滤泡数量减少亦稍较VacA^-组明显（P＝0．051）,两组患者的胃粘膜萎缩和肠化程度均无明显好转。结论：中国上消化道疾病患者H.pylori感染根除前后的胃粘膜病理改变与VacA活性无明显关系。成功根除H.pylori感染并不引起萎缩和肠化的逆转。     

A low prevalence of H pylori and endoscopic findings in HIV-positive Chinese patients with gastrointestinal symptoms

AIM： To compare the prevalence of H pylori infection, peptic ulcer, cytomegalovirus （CNV） infection and Candida esophagitis in human immunodeficiency virus （HIV）- positive and HIV-negative patients, and evaluate the impact of CD4 lymphocyte on H pylori and opportunistic infections.
METHODS： A total of 151 patients （122 HIV-positive and 29 HIV-negative） with gastrointestinal symptoms were examined by upper endoscopy and biopsy. Samples were assessed to determine the prevalence of Hpylori infection, CMV, candida esophagitis and histologic chronic gastritis.
RESULTS： The prevalence of Hpylori was less common in HIV-positive patients （22.1%） than in HIV-negative controls （44.8%; P 〈 0.05）, and the prevalence of H pylori displayed a direct correlation with CD4 count stratification in HIV-positive patients. In comparison with HIV-negative group, HIV-positive patients had a lower incidence of peptic ulcer （20.7% vs 4.1%; P 〈 0.01）, but a higher prevalence of chronic atrophy gastritis （6.9% vs 24.6%; P 〈 0.05）, Candida esophagitis and CMV infection. Unlike HIV-negative group, H pylori infection had a close relationship to chronic active gastritis （P 〈 0.05）. In HIV-positive patients, chronic active gastritis was not significantly different between those with Hpylori infection and those without.
CONCLUSION： The lower prevalence of H pylori infection and peptic ulcer in HIV-positive patients with gastrointestinal symptoms suggests a different mechanism of peptic ulcerogenesis and a different role of H pylori infection in chronic active gastritis and peptic ulcer. The pathogen of chronic active gastritis in HIV-positive patients may be different from the general population that is closely related to Hpylori infection.     

A low prevalence of H pylori and endoscopic findings in HTV-positive Chinese patients with gastrointestinal symptoms

AIM: To compare the prevalence of H pylori infection,peptic ulcer, cytomegalovirus (CMV) infection and Candida esophagitis in human immunodeficiency virus (HIV)-positive and HIV-negative patients, and evaluate the impact of CD4 lymphocyte on H pylori and opportunistic infections.METHODS: A total of 151 patients (122 HIV-positive and 29 HIV-negative) with gastrointestinal symptoms were examined by upper endoscopy and biopsy. Samples were assessed to determine the prevalence of H pylori infection,CMV, candida esophagitis and histologic chronic gastritis.RESULTS: The prevalence of H pylori was less common in HIV-positive patients (22.1%) than in HIV-negative controls (44.8%; P ＜ 0.05), and the prevalence of H pylori displayed a direct correlation with CD4 count stratification in HIV-positive patients. In comparison with HIV-negative group, HIV-positive patients had a lower incidence of peptic ulcer (20.7% vs 4.1%; P ＜ 0.01), but a higher prevalence of chronic atrophy gastritis (6.9% vs 24.6%; P ＜ 0.05), Candida esophagitis and CMV infection. Unlike HIV-negative group, H pylori infection had a close relationship to chronic active gastritis (P＜0.05). In HIV-positive patients, chronic active gastritis was not significantly different between those with H pylori infection and those without.CONCLUSION: The lower prevalence of H pylori infection and peptic ulcer in HTV-positive patients with gastrointestinal symptoms suggests a different mechanism of peptic ulcerogenesis and a different role of H pylori infection in chronic active gastritis and peptic ulcer.The pathogen of chronic active gastritis in HIV-positive patients may be different from the general population that is closely related to H pylori infection.     

A low prevalence of H pylori and endoscopic findings in HIV-positive Chinese patients with gastrointestinal symptoms

AIM: To compare the prevalence of H pylori infection,peptic ulcer,cytomegalovirus (CMV) infection and Candida esophagitis in human immunodeficiency virus (HIV)-positive and HIV-negative patients,and evaluate the impact of CD4 lymphocyte on H pylori and opportunistic infections. METHODS: A total of 151 patients (122 HIV-positive and 29 HIV-negative) with gastrointestinal symptoms were examined by upper endoscopy and biopsy. Samples were assessed to determine the prevalence of H pylori infection,CMV,candida esophagitis and histologic chronic gastritis. RESULTS: The prevalence of H pylori was less common in HIV-positive patients (22.1%) than in HIV-negative controls (44.8%; P < 0.05),and the prevalence of H pylori displayed a direct correlation with CD4 count stratification in HIV-positive patients. In comparison with HIV-negative group,HIV-positive patients had a lower incidence of peptic ulcer (20.7% vs 4.1%; P < 0.01),but a higher prevalence of chronic atrophy gastritis (6.9% vs 24.6%; P < 0.05),Candida esophagitis and CMV infection. Unlike HIV-negative group,H pylori infection had a close relationship to chronic active gastritis (P < 0.05). In HIV-positive patients,chronic active gastritis was not significantly different between those with H pylori infection and those without. CONCLUSION: The lower prevalence of H pylori infection and peptic ulcer in HIV-positive patients with gastrointestinal symptoms suggests a different mechanism of peptic ulcerogenesis and a different role of H pylori infection in chronic active gastritis and peptic ulcer. The pathogen of chronic active gastritis in HIV-positive patients may be different from the general population that is closely related to H pylori infection.     

Clinical relevance of Helicobacter pylori CagA-positive strains: gastroduodenal peptic lesions marker.

OBJECTIVES: peptic ulcer is characterized by its recurrent nature, which necessitates maintenance treatment in most patients. But this natural history can be changed in patients with peptic ulcer associated to Helicobacter pylori, as shown by the low rates of recurrence and decreased hemorrhagic recidivism associated with this infection. Whether CagA or VacA strains are associated with a greater risk of peptic ulcer is controversial. This study was designed to examine endoscopic findings and their relation with H. pylori phenotype (CagA or VacA). METHODS: 106 selected dyspeptic patients underwent upper gastrointestinal tract endoscopic examination between September 1996 and May 1997 [69 with H. pylori (Hp) and 37 without this infection]. Endoscopic findings were classified as gastric ulcer (GU), duodenal ulcer (DU), gastric erosions (GE), duodenitis (Du), chronic gastritis (CG) and normal mucosa (NM). Hp phenotype was analyzed with a western blot test. RESULTS: 75% of H. pylori strains were CagA-positive and 54.2% were VacA-positive. 82.4% of the cases of DU were associated with a CagA+ phenotype, but the association was not statistically significant. Otherwise 100% of gastric ulcers were associated with CagA+ strains (p < 0.005). VacA phenotype was not associated with any particular endoscopic finding. Peptic ulcer (DU or GU) was also associated with the CagA+ phenotype (p < 0.05). CONCLUSIONS: the CagA+ H. pylori phenotype seems to be a peptic lesion marker, but was more frequently related with GU than with DU in our sample of Spanish patients.     

幽门螺杆菌上皮接触诱导基因iceA1的克隆及序列特征

目的:克隆和分析镇江地区来源于不同疾病的(胃癌、溃疡和胃炎)幽门螺杆菌(Helicobacter pylori,H.pylori)的表皮接触诱导基因iceA1.方法:从胃十二指肠疾病患者胃黏膜组织中分离培养获得H.pylori,PCR扩增检测iceA1基因,并克隆至pMD18-T载体上,进行测序和序列分析.结果:克隆和测序了镇江地区来源于不同疾病的(胃癌、溃疡和胃炎)共12株H.pylori的i c e A1基因片段,并与标准菌株60190比对,结果显示镇江地区的H.pylori的iceA1基因中存在着3处框内缺失突变热点(780del6、809del5、914del7),这些缺失突变在溃疡和胃炎中均存在,但是胃癌株只存在809del5.对缺失片段周围的序列进行分析,这些缺失序列的两端基本都与同向重复序列相连,这可能与复制过程中滑动错配的小片段缺失模型有关.结论:iceA1序列的变异性有可能作为分析H.pylori群体遗传学的有用工具.     

H pylori infection among 1000 southern Iranian dyspeptic patients

INTRODUCTION H pylori is a major cause of gastritis and peptic ulcer disease (PUD), and has been implicated in the development of gastric malignancy[1-3]. The prevalence of H pylori, a worldwide infection, varies greatly among countries and among populati…     

Association of cytotoxin production and neutrophil activation by strains of Helicobacter pylori isolated from patients with peptic ulceration and chronic gastritis.

BACKGROUND: Helicobacter pylori is associated with neutrophil infiltration within the gastroduodenal mucosa. Neutrophil activation provides a major source of oxygen free radicals, which have been implicated in the pathogenesis of peptic ulceration. AIM: To investigate if cytotoxin producing strains of H pylori are associated with the generation of oxidative burst in polymorphonuclear neutrophils (PMNs). PATIENTS: 76 patients undergoing endoscopy of whom 45 had peptic ulcer and 31 chronic gastritis only were studied. METHODS: Strains of H pylori were cultured in Brucella broth. After 48 hours, bacteria were harvested by centrifugation and a bacterial suspension prepared as a stimulus for PMN oxidative burst using chemiluminescence. PMNs were prepared from health blood donors. To test the ability of strains to produce cytotoxin, culture supernatants of each were concentrated by polyethylene glycol and tested on cultured Vero cells for intracellular vacuolation. RESULTS: 30 of 45 (66.7%) peptic ulcer patients induced cell vacuolation versus nine of 31 (29%) strains from patients with chronic gastritis only (p < 0.01). Cytotoxin positive strains of H pylori regardless of the presence or absence of peptic ulcer displayed an increased induction of respiratory burst in PMNs compared with toxin negative strains from patients with chronic gastritis only (p < 0.05). Among the toxin negative strains, those from patients with peptic ulcer did not show a significant increase of the oxidative burst than those from patients without peptic ulcer (NS). CONCLUSION: Toxinogenicity of strains of H pylori seems to be correlated with neutrophil respiratory burst and peptic ulceration. The ability of some strains of H pylori to produce cytotoxin and to induce the oxidative burst in neutrophils may be important in the pathogenesis of peptic ulcer disease.     

幽门螺杆菌感染对胃黏膜病理变化的影响

背景：幽门螺杆菌(H．pylori)感染已被公认为慢性胃炎和消化性溃疡的重要危险因素，根除H．pylori能加速消化性溃疡的愈合，但其对胃黏膜病理变化的影响尚有待进一步探索。目的：了解根除H．pylori对慢性胃炎胃黏膜病理变化和癌前状态的影响。方法：采用多中心随机对照临床试验和回顾性队列研究，样本选自胃癌高发区：上海郊区的金山区和奉贤区。共纳入360例经内镜检查证实有H．pylori感染的慢性胃炎伴或不伴十二指肠溃疡患者，随机分为两组。治疗组用三联疗法(质子泵抑制剂或Hz受体阻滞剂加两种抗生素)治疗，对照组单纯慢性胃炎患者予西沙必利、十二指肠溃疡患者予西米替丁治疗。在第1年和第4年末随访胃镜，根据H．pylori是否根除将患者分为两组：H．pylori阳性组和H．pylori阴性组。所有胃黏膜活检标本由两位病理科医师统一复读。结果：至第4年末，有120例患者完成全部随访，其中H．pylori持续根除组54例，阳转组5例；H．pylori持续未根除组45例，阴转组16例。持续根除组第1年随访时，活动性炎症比例减少(P＜O．05)；第4年随访时，慢性炎症和肠化程度以及活动性炎症比例减少(P＜O．05)。持续未根除组第1年随访时，慢性炎症程度增加(P＜O．05)；第4年随访时，慢性炎症和肠化程度以及活动性炎症比例增加(P＜O．05)，萎缩程度较第1年随访时增加(P＜O．05)。结论：根除H．pylori可以减轻慢性胃炎的炎症程度，防止肠化的发生和发展。     

Helicobacter pylori cagA, iceA and vacA genotypes in patients with gastric cancer in Taiwan

AIM: Helicobacter pylori (H pylori ) has been linked to chronic gastritis, peptic ulcer, gastric cancer and MALT-lymphoma. The link of genotypes of H pylori to gastric cancer remains controversial. The aim of this study was to investigate the H pylori vacA alleles, cagA and iceA in patients with gastric cancer in Taiwan. METHODS: Patients with gastric cancer, peptic ulcer and chronic gastritis were enrolled in this study. We obtained biopsy specimens from the stomach at least 2 cm away from the tumor margin in patients with gastric cancer, and from the antrum of stomach in patients with peptic ulcer or chronic gastritis. DNA extraction and polymerase chain reaction were used to detect the presence or absence of cagA and to assess the polymorphism of vacA and iceA. RESULTS: A total of 168 patients (gastric ulcer: 77, duodenal ulcer: 66, and chronic gastritis: 25) were found to have positive PCR results of the biopsy specimens from patients with peptic ulcer and chronic gastritis. We found positive cagA (139/168, 83%), m2 (84/168, 50%) and iceA1 (125/168, 74%) strains in the majority of patients. In patients with gastric cancer, the vacA s1a and s1c subtypes were less commonly found than those in non-cancer patients (35/66 vs 127/168, P = 0.0001 for s1a and 13/66 vs 93/168, P<0.0001 for s1c). In the middle region, the m1T strain in patients with gastric cancer was more than that of non-cancer patients (23/66 vs 33/168, P = 0.02). CONCLUSION: In Taiwan, H pylori with positive vacA s1a, cagA and iceA1 strains are found in the majority of patients with gastric cancer or non-cancer patients. In patients with gastric cancer, the vacA s1a and s1c subtypes are less and m1T is more than in patients with peptic ulcer and chronic gastritis.     

河西走廊地区上消化道疾病患者幽门螺杆菌耐药性分析

目的研究河西走廊地区上消化道疾病患者幽门螺杆菌(Hp)的感染及对抗生素的耐药状况。方法收集武威、金昌、张掖三地患者的胃黏膜标本,微需氧培养分离Hp,K-B纸片法检测Hp对6种抗菌药物的耐药性。结果从314例患者中分离出Hp 81株,分离率25.80%;消化性溃疡患者中Hp的分离阳性率(46.43%)显著高于慢性胃炎组(23.32%)(P<0.05),15～30岁年龄组人群Hp分离阳性率(52.63%)显著高于61岁以上年龄组(13.16%)(P<0.05)。Hp对常用6种抗菌药物的耐药性依次为:甲硝唑(47.89%),左氧氟沙星(8.45%),阿莫西林(4.23%),四环素(2.82%),克拉霉素(1.41%),呋喃唑酮(0)。胃癌组分离的Hp对左氧氟沙星的耐药率(37.50%)显著高于慢性胃炎组(3.85%)。结论 Hp感染在河西走廊地区上消化道疾病中伴有重要角色;该地区流行的Hp对甲硝唑耐药率较高,在一线根除方案中应尽量避免使用该药物;呋喃唑酮、阿莫西林等可以作为根除治疗的主要药物。     

幽门螺杆菌感染途径的探讨

目的检测幽门螺杆菌（Helicobacter pylori,Hp）感染慢性胃炎、消化性溃疡和胃癌患者的粪便是否存在活的Hp,以探讨Hp的传播途径。方法收集60例胃粘膜快速尿素酶试验强阳性患者的胃粘膜和新鲜粪便,进行Hp的分离培养和PCR检测。结果52份胃粘膜标本分离到Hp,阳性率86.7%;6份粪便标本分离到Hp,阳性率10.0%,其中4份来自慢性胃炎患者,2份来自消化性溃疡患者。粪便培养阳性的患者胃粘膜培养均阳性;PCR检测同一患者两种标本分离菌株的细胞毒素相关蛋白基因（CagA）和空泡毒素信号序列s1a基因（VacA s1a）一致,其中4株为CagA＋和VacA s1a＋,另2株VacA s1a＋和尿素酶A亚单位（UreA）基因阳性。结论Hp感染者的粪便中有活的Hp存在,该菌可能通过粪-口途径传播。     

Helicobacter pylori vacuolating cytotoxin, VacA

Helicobacter pylori is the leading bacterial cause of food-borne illness worldwide and plays a major role in the development of chronic gastritis, peptic ulcer, and gastric cancer. Strains isolated from patients contain the cagA gene (cytotoxin-associated gene A) and produce the vacuolating cytotoxin, VacA. Recent molecular and cellular studies of VacA action have begun to unravel its structure and the details of the mechanism of gastric injury caused by H. pylori infection.     

贵州省幽门螺杆菌临床菌株的抗生素耐药现状

目的检测贵州省幽门螺杆菌(Helicobacter pylori,H.pylori)临床菌株对多种抗生素的耐药率,并分析甲硝唑(MTZ)、克拉霉素(CLA)、阿莫西林(AMO)耐药菌株的临床特征。方法以贵州地区30株培养成功的H.pylori临床菌株为研究对象,采用Kirby-Bauer及E-test法测定菌株对MTZ、CLA、AMO等多种抗生素的耐药性。分析MTZ、CLA、AMO耐药菌株与敏感菌株患者性别、年龄及疾病种类的差异。结果 Kirby-Bauer法显示H.pylori临床菌株对AMO、左氧氟沙星、庆大霉素、CLA、四环素、头孢呋肟、复方新诺明的耐药率分别为20.00%、3.33%、13.33%、30.00%、6.67%、0、0;E-test法显示H.pylori临床菌株对MTZ、AMO、CLA耐药率分别为63.33%、26.67%、33.33%;两种检查方法检测结果无明显差异;男性患者MTZ的耐药率(77.78%)较女性患者(41.67%)高(P<0.05);30～60岁年龄组患者MTZ的耐药率更高(P<0.05);CLA和AMO的耐药率与疾病种类、性别、年龄无明显关系(P>0.05)。结论贵州地区H.pylori临床菌株的耐药现状不容忽视,以男性消化性溃疡患者年龄在30～60岁对MTZ的耐药率较高。     

Mucosal polymerase chain reaction for diagnosing Helicobacter pylori infection in patients with bleeding peptic ulcers

AIM: Helicobacter pylori (H pylon) has been linked to chronic gastritis, peptic ulcers, gastric cancer and MALT-lymphoma. Conventional invasive tests are less sensitive than non-invasive tests in diagnosing H pylori infection in patients with bleeding peptic ulcers. Polymerase chain reaction is a sensitive and accurate method for diagnosing H pylori infection. The aim of this study was to evaluate the diagnostic role of mucosai polymerase chain reaction for H pylori infection in patients with bleeding peptic ulcers. METHODS: In patients with bleeding, non-bleeding peptic ulcers and chronic gastritis, we checked rapid urease test, histology, bacterial culture and mucosai polymerase chain reaction fordetecting H pylori infection. Positive H pylori infection was defined as positive culture or both a positive histology and a positive rapid urease test. For mucosai polymerase chain reaction of H pylori, we checked vacA (s1a, s1b, s1c, s2, m1, m1T, m2), iceA1, iceA2. and cag A. RESULTS: Between October 2000 and April 2002,88 patients with bleeding peptic ulcers (males/females: 60/28, gastric ulcers/duodenal ulcers: 55/33), 81 patients with non-bleeding peptic ulcers (males/females: 54/27, gastric ulcers/duodenal ulcers: 45/36) and 37 patients with chronic gastritis (males/ females: 24/13) were enrolled in this study. In patients with bleeding peptic ulcers, non-bleeding peptic ulcers and chronic gastritis, 45 patients (51%), 71 patients (88%) and 20 patients (54%) respectively were found to have positive H pylori infection (P<0.001). In patients with bleeding peptic ulcers, non-bleeding peptic ulcers and chronic gastritis, polymerase chain reaction for H pylori infection was positive in 54 patients (61%), 70 patients (86%) and 20 patients (54%) respectively (P<0.001). The sensitivity, positive predictive value and diagnostic accuracy of mucosai polymerase reaction for H pylori infection were significantly lower in patients with bleeding peptic ulcers (84%, 79% and 81%) than in patients with non-bleeding peptic ulcers (99%, 99% and 98%) (P<0.001, P<0.01 and P<0.001 respectively). The sensitivity, negative predictive value and diagnostic accuracy of mucosal polymerase reaction for H py/ori were significantly lower in patients with bleeding peptic ulcers (84%, 83% and 81%) than in patients with chronic gastritis (100%, 100% and 100%) (P= 0.02, P= 0.02 and P=0.001). CONCLUSION: Mucosal polymerase chain reaction for detecting H pylori infection is not reliable in patients with bleeding peptic ulcers.     

Association of peptic ulcer with increased expression of Lewis antigens but not cagA, iceA, and vacA in Helicobacter pylori isolates in an Asian population

BACKGROUND: Studies in Western populations suggest that cagA, iceA, and vacA gene status in Helicobacter pylori isolates is associated with increased virulence and peptic ulcer disease. AIM: To investigate the relationship between peptic ulcer and expression of Lewis (Le) antigens as well as cagA, iceA, and vacA in H pylori isolates in Singapore. METHODS: Expression of Le antigens in H pylori isolates obtained from patients with dyspepsia was measured by enzyme linked immunosorbent assay. The cagA, iceA, and vacA status was determined by polymerase chain reaction. RESULTS: Of 108 H pylori isolates, 103 (95.4%) expressed Le(x) and/or Le(y), while Le(a) and Le(b) were expressed in 23 (21.3%) and 47 (43.5%) isolates, respectively. Expression of two or more Le antigens (Le(x), Le(y), Le(a), or Le(b)) was significantly higher in H pylori isolated from ulcer patients than in non-ulcer patients (89.6% v 73.2%, p=0.035). There were no significant differences in the prevalence of cagA or iceA1 in H pylori isolates from peptic ulcer and non-ulcer patients (86.6% v 90.2% for cagA; 70.1% v 68.3% for iceA1), and no association of peptic ulcer with any specific vacA genotype. CONCLUSIONS: The present study indicates that peptic ulcer disease is associated with increased expression of Lewis antigens but not cagA, iceA, or vacA genotype in H pylori isolates in our population. This suggests that cagA, iceA, and vacA are not universal virulence markers, and that host-pathogen interactions are important in determining clinical outcome.     

优化构建UreB/HpaA双价幽门螺杆菌减毒活菌疫苗的免疫保护作用

目的 以减毒鼠伤寒沙门菌为载体，通过在UreB和HpaA间引入由3个甘氨酸残基组成的三肽柔韧接头，构建成UreB／HpaA双价抗幽门螺杆菌(Hp)活疫苗，并对照相应单价疫苗和空白载体研究其对C57BL／6小鼠的免疫保护效果。方法 用序列重叠延伸聚合酶链反应扩增带3个甘氨酸残基柔韧接头的融合基因UreB／HpaA，进一步以减毒鼠伤寒沙门菌SL3261为载体构建UreB／HpaA双价活疫苗，观察其在小鼠体内的稳定性。用双价活疫苗株免疫Ⅱ级C57BL／6小鼠1次，对照单价活疫苗和空白载体观察其在体内诱导的特异抗体反应和对小鼠的免疫保护作用。结果 测序结果显示，3个甘氨酸残基的编码序列GGTGGAGGC已成功地插入UreB／HpaA融合基因中。双价疫苗灌喂小鼠后，至少能在脾脏和回肠末段存留10d。双价疫苗在小鼠体内诱导血清特异性IgGl和IgG2a水平明显升高。UreB／HpaA双价疫苗的免疫保护率为77．3％(17／22)，而UreB疫苗和HpaA疫苗的免疫保护率分别为50．0％(12／24)和43．5％(10／23)。结论 引入柔韧接头，优化构建表达UreB和HpaA的双价抗Hp活疫苗。UreB／HpaA双价活疫苗对Ⅱ级C57BL／6小鼠有更好的免疫保护作用。