Helicobacter pylori and the innate immune system

Since its discovery, Helicobacter pylori surprises us by its ability for life-long chronic persistence, proliferation, and probably active adaptation in the unfavourable niche of the human stomach, without being eliminated by the defence systems of the human body. This minireview highlights recent developments about the interaction of H. pylori with the innate immune system, and makes a case that evasion and possibly suppression of innate immune responses play an important role for the active survival in its local mucosal environment.     

Effect of antioxidants on the immune response of Helicobacter pylori

Antioxidants are substances capable of inhibiting oxidation. In chronic diseases, inflammatory response cells produce oxygen free radicals. Oxygen free radicals cause DNA damage, and this may lead to gene modifications that might be carcinogenic. Chronic Helicobacter pylori infection causes the production of DNA-damaging free radicals. In recent years, various groups have studied the effects of antioxidants, especially on H. pylori -associated gastric cancer. In most of the studies, it has been shown that H. pylori infection does affect the level of antioxidants measured in the gastric juice, but there are also controversial results. Recent experimental studies, both in vivo and in vitro, have shown that vitamin C and astaxanthin, a carotenoid, are not only free radical scavengers but also show antimicrobial activity against H. pylori. It has been shown that astaxanthin changes the immune response to H. pylori by shifting the Th1 response towards a Th2 T-cell response. Very few experimental studies support the epidemiologic studies, and further studies are needed to describe the effect and the mechanism of antioxidants in the H. pylori immune response.     

幽门螺旋杆菌引起胃黏膜免疫损伤机制研究进展

幽门螺旋杆菌(Helicobacter plyori,Hp)是消化道疾病最常见的病因,通过多种机制诱导炎症通路激活、免疫细胞及炎症因子释放改变胃黏膜周围微环境引起慢性炎症,持久性的慢性炎症可导致胃黏膜萎缩、甚至诱发胃癌.正常机体T淋巴细胞在免疫反应中起主导作用,其中正向调节与负向调节系统相互诱导和制约T细胞网络维持免疫系统平衡,当Hp感染后两项调节比例出现异常,导致免疫系统紊乱从而引起免疫损伤.近年来免疫细胞的分子生物学研究已经成为临床过继性细胞免疫治疗的理论基础.     

幽门螺杆菌相关抗原及宿主免疫应答的研究进展

幽门螺杆菌与多种胃肠道疾病诸如慢性胃炎,胃肠溃疡,胃腺瘤及胃癌等密切相关的结论已得到证实,预防和治疗幽门螺杆菌感染是控制其广泛传播的有效途径,此项工作虽早已开始,但至今未找到可行的方案.近来对幽门螺杆菌相关毒素的研究越来越多,这可作为研究幽门螺杆菌菌苗的重要依据;幽门螺杆菌诱发的宿主免疫应答以TH1反应为主,幽门螺杆菌感染者可出现系统和局部的抗体反应,这些抗体反应对机体不具保护作用且自身抗体对宿主上皮细胞还可能带来不良影响,阐明宿主免疫应答的机制对预防和治疗幽门螺杆菌感染具特殊意义.因此,本文主要介绍了脲素酶、空泡细胞毒素、cag相关基因蛋白,中性粒细胞蛋白等几种毒素及宿主免疫应答的研究现状,并对幽门螺杆菌的研究前景进行综述.     

幽门螺杆菌疫苗免疫机制的研究进展

幽门螺杆菌(H.pylori)是定植于人体胃粘膜的重要致病菌,而粘膜疫苗以其有效的保护性免疫成为防治H.pyiori的热点,但对相应的免疫机制的认识目前尚不明确.故本文对H.pyiori疫苗的保护性免疫机制中的抗原递呈机制,抗体的作用以及TH细胞反应的作用等研究进展做一概要介绍.     

Virulence factors of Spanish Helicobacter pylori isolates and correlation with gastritis or ulcer production

Objective: To study the cagA , vacA and iceA status of Helicobacter pylori clinical isolates obtained from adult patients suffering from peptic ulcer or gastritis in order to find if these virulence factors are useful in determining a strain to be a gastritis or ulcer producer.
Methods: One hundred and five H. pylori strains from patients with gastritis and ulcer were studied. Culture and identification was done by standard methodology. cagA, vacA and iceA detection was performed by PCRs previously described. Results were visualized by agarose gel electrophoresis.
Results: Amplified fragments of 297 bp ( cagA ), 259 bp ( vacA s1), 286 bp ( vacA s2) and 975 bp ( iceA ) were detected. cagA was detected in 83.3% and 91.3% of gastritis and ulcer strains respectively (p>0.05). s1 was detected in 57.1% of gastritis strains and 62.3% of ulcer strains (p>0.05). cagA was strongly related with the s1 allele. iceA was more prevalent in strains from gastritis (82.4% versus 66.7%). The combination of cagA, vacA and iceA was not correlated with the production of peptic ulcer disease.
Conclusions: These data suggest that the combination of cagA, vacA and iceA cannot be used to predict severe gastric disease in Spanish H. pylori clinical isolates.     

重组幽门螺杆菌疫苗免疫保护作用与免疫后胃炎

目的：研究以减毒鼠伤寒沙门菌为载体构建的幽门螺杆菌(Helicobacter pylori，Hp)疫苗的免疫保护机制。方法：将表达不同Hp抗原的减毒鼠伤寒沙门菌(Salmonella typhimurium)分别免疫小鼠，免疫4周后以Hp攻击；在攻击前及攻击后5周分批处死小鼠，比较各组小鼠Hp定植密度及各项免疫指标的变化。结果：(1)和NS(Normal salin，NS)对照组相比各免疫组的Hp定植密度显著下降。(2)和NS组相比攻击前后各免疫组血清IgG2a和胃黏膜Th1型细胞因子表达显著升高。(3)和NS组相比攻击后免疫组鼠胃黏膜出现明显的炎症反应。结论：以减毒鼠伤寒沙门菌为载体构建的重组幽门螺杆菌疫苗在小鼠体内诱导出以Th1反应为主并伴随免疫后胃炎的保护性免疫应答。     

幽门螺杆菌微球疫苗免疫诱导的免疫应答

目的通过对幽门螺杆菌微球免疫后Balbc小鼠血清IgG、IgA、胃肠sIgA的检测及脾脏IL4、IFNγ的mRNA表达水平、IgGASC、IgAASC数量的比较观察,探求疫苗的免疫保护机理。方法取Balbc小鼠口服免疫疫苗,剂量为150μg/(只·次),免疫时间为0、14、30d。2周后取血清及胃肠洗液进行抗体检测,同时取脾脏检测细胞因子mRNA表达水平及ELISPOT检测抗体分泌细胞数量变化。结果免疫后小鼠以上检测指标与对照组比较均有不同程度的升高。结论微球疫苗所诱发的免疫保护是细胞免疫、体液免疫两者共同作用的结果。     

Humoral and cellular immune recognition of Helicobacter pylori proteins are not concordant.

Helicobacter pylori is a major cause of chronic antral gastritis and peptic ulcer disease. Further definition is needed of the factors that determine whether infected individuals remain asymptomatic, or ultimately develop ulceration of the mucosa or transformation to malignancy. To explore the possibility that host response to H. pylori may play a role in the outcome of this infection, we have examined humoral and cellular recognition of several H. pylori proteins by seropositive and seronegative persons. A complex mixture of water-extractable cell proteins, which did not include lipopolysaccharide (LPS), was recognized by serum antibodies only in seropositive or infected individuals. IgG from seropositive subjects also bound to urease and to a heat shock protein (hsp)60 that is homologous to the 65-kD mycobacterial heat shock protein, while sera from uninfected individuals were negative. Although antibody responses to these antigens were restricted to seropositive subjects, T cell recognition of the same proteins was found in both seropositive and seronegative subjects. The water extract of H. pylori stimulated peripheral blood mononuclear cells (PBMC) from all subjects, while purified proteins activated lymphocytes of only some seropositive and seronegative subjects. PBMC that were activated by the H. pylori hsp60 did not respond to the autologous human p60 heat shock protein. These results demonstrate that, in contrast to antibody responses, T cell recognition of H. pylori proteins may occur in non-infected persons. In addition, the data suggest that in these subjects, peripheral lymphocytes that are activated by bacterial heat shock proteins do not mediate tissue damage by recognition of human heat shock homologues.     

IgG subclass response to Helicobacter pylori and CagA antigens in children

Specific serum IgG subclass antibodies against Helicobacter pylori antigens and recombinant CagA were analysed in 75 symptomatic children with histologically confirmed H. pylori infection. H. pylori stimulated an IgG1 predominant response, and IgG3 titres showed a positive association with peptic ulcer disease, chronicity of antral inflammation and density of H. pylori colonization. Two methods used for assessing serum IgG CagA antibody status, i.e. Western blotting and enzyme-linked immunosorbent assay (ELISA), were concordant. CagA stimulated an IgG1 and IgG3 predominant humoral response. Total CagA IgG titres were higher in children with active and more severe chronic antral inflammation. These findings suggest that in children the systemic humoral immune response to H. pylori infection may reflect gastroduodenal pathology.     

幽门螺杆菌尿素酶B亚单位W/O/W型复乳剂的研制

目的 制备重组幽门螺杆菌尿素酶B亚单位(rUreB)复乳剂，研究其物理性质及免疫效率。方法 设计处方采用二步法制备复乳，显微镜观察乳滴结构及粒径分布，以电导法测定包封率，以经典法、离心法及电导法观察复乳的稳定性，免疫印迹观察抗原制备成复乳剂后免疫反应性的变化，以动物实验观察rUreB复乳的免疫效率。结果 制备的rUreB复乳性质稳定、包封率98．3％、粒径大小主要在2～10μm，免疫印迹及小鼠口服免疫后特异性抗体测定结果表明，该复乳具有良好的免疫原性，剂量小、免疫效率高。结论 将幽门螺杆菌尿素酶B亚单位制备成复乳剂可得到高效、廉价、使用方便的疫苗，复乳是一个很有潜力的黏膜疫苗传送系统。     

One-step polymerase chain reaction-based typing of Helicobacter pylori vacA gene: association with gastric histopathology

Heterogeneity of the Helicobacter pylori vacA gene may be associated with bacterial virulence and presentation. In this study, the possible correlation between vacA genotypes and gastric histopathology was investigated. Using a modified one-step polymerase chain reaction (PCR)-based method, 122 of 131 H. pylori isolates obtained from 63 of 67 patients from Germany were classified into distinct vacA genotypes according to their signal sequence (s1 or s2) and their midregion alleles (m1 or m2). A possible subtype of m1, now alluded to as m3, was identified in one-third of the isolates. Signal sequence s1 was significantly associated with higher H. pylori density but not with gastric inflammation parameters as compared with s2. Compared with m2, m1 initially appeared to correlate with higher mononuclear cell scores in corpus, although not with H. pylori density. Upon differentiation between m1 and m3, however, only the latter was associated with the high cell scores. Moreover, m3 also correlated with a higher antral H. pylori density. Positive cagA status correlated significantly with vacA signal sequence s1, and higher gastric mononuclear cell scores and corpus neutrophil score. H. pylori density was always associated with enhanced gastric neutrophil and corpus mononuclear cell scores. These data indicate a significant association of specific vacA genotypes with enhanced bacterial density and gastric inflammation. PCR-based identification of the respective alleles can now easily be performed in the diagnostic laboratory using a one-step PCR assay. Received: 6 September 1999     

Prevalence and risk factors of Helicobacter pylori infection in Chinese maritime workers

Abstract

Background: Helicobacter pylori infection is very common worldwide.

Aim: To evaluate the prevalence and identify the risk factors for Helicobacter pylori infection in Chinese maritime workers.

Subjects and methods: Between March 2010 and October 2010, 3995 subjects were selected in the Hospital of Dalian Port. The presence of Helicobacter pylori infection was confirmed using laboratory tests (serum IgG anti-Helicobacter pylori antibodies) and background information, family history, lifestyle and eating habits were collected using questionnaires.

Results: The prevalence of Helicobacter pylori infection was 44.9% in these Chinese maritime workers. Prevalence of Helicobacter pylori infection was associated with family income, living space, family history of gastrointestinal diseases, smoking, drinking tea, raw vegetables consumption, spicy food, pickle food, dining outside, no regular meal and dish sharing. Further analysis with multivariate logistic regression analysis indicated that raw vegetables consumption, pickle food consumption, family income and family history of gastrointestinal diseases were independent predictors for Helicobacter pylori infection. No association was found between infection and gender, marital status, education, alcohol consumption and tap water consumption.

Conclusion: Helicobacter pylori infection is associated with raw vegetables consumption, pickle food consumption, family income and family history of gastrointestinal disease among Chinese maritime workers.     

Balb/c小鼠口服幽门螺杆菌疫苗rLTB-HspA的免疫应答

目的　研究幽门螺杆菌 (Hp)热休克蛋白A (rHspA)与大肠杆菌不耐热肠毒素B亚单位 (LTB)融合蛋白 (rLTB HspA)作为口服疫苗的免疫应答效果。方法　采用rLTB HspA口服免疫Balb c小鼠 ,ELISA分析小鼠血清、胃肠黏液中IgG、IgA抗体水平 ,体外培养脾淋巴细胞在Hp刺激下的增殖情况及IL 4、IFN γ的变化。结果　Balb c小鼠口服rLTB HspA能有效激发机体产生全身和局部特异性的体液免疫应答和细胞免疫应答。结论　Balb crLTB HspA可作为预防和治疗Hp感染的候选疫苗之一     

幽门螺杆菌免疫奶羊的应答性实验研究

目的　以Hp全菌抗原免疫奶羊 ,观察羊奶中特异性抗体产生规律。方法　采用 6× 10 9CFU mLHp全菌抗原 ,通过滴鼻、多点皮下注射、妊娠期肌肉注射 3种途径免疫 3只产奶山羊。前两组于 0、14、2 1、2 8d接受 4次免疫接种 ,妊娠组于分娩前后 1个月每隔两周注射 1次。收集血清、乳清 ,以酶联免疫吸附试验进行样本中的IgA、IgG抗体测定。结果　 3种途径免疫奶羊后都激发了奶羊的系统免疫 ,使血清中IgG较免疫前都有很大升高 ;羊奶中IgA抗体水平滴鼻组 >妊娠组 >皮下组 ,IgG抗体水平妊娠组 >皮下组 >滴鼻组。结论　 3种途径都能激发奶羊机体的免疫应答 ,尤其是滴鼻免疫能够诱导机体同时产生不同部位的粘膜免疫和系统免疫 ,是一种敏感、安全、可行有效的免疫途径     

幽门螺杆菌粪便抗原检测方法学评价

目的 评价幽门螺杆菌粪便抗原（ HpSA）检测在诊断患者幽门螺杆菌（Hp）感染中的价值.方法 以胃镜病理学诊断结果为金标准,对328例有消化道症状患者粪便,同时应用酶联免疫吸附实验检测幽门螺杆菌粪便抗原,计算HpSA检测诊断Hp感染的特异性、灵敏度和准确性等性能指标.结果 幽门杆菌粪便抗原酶免疫检测法对Hp感染诊断与金标准相比无统计学差异（P＞0.05）,其敏感性为94.6％、特异性为96.9％、准确性为96.3％、阳性预期值为89.7％、阴性预期值为98.4％.结论 幽门螺杆菌粪便抗原酶免疫检测是一种简便、易行、准确性高、便宜、易重复的非侵入性检测方法.     

幽门螺杆菌L型微结构的研究

扫描电镜发现幽门螺杆菌的Ｌ型与其它细菌的Ｌ型一样形态不规则，呈多形性，有圆球体、巨形体、短杆状、串珠状和腊肠样，大小不等。超薄切片可见细胞壁部分或完全缺失，菌体内部结构稀疏，电子密度降低，部分菌体含有大量原生小体，有的正从细胞内释放出来，是细菌Ｌ型繁殖的方式之一。