Virulence and Colonization‐Associated Properties of<i>Helicobacter pylori</i>Isolated from Children and Adolescents

Çelik, Janet; Su, Bai-Horng; Tirén, Urban; Finkel, Yigael; Thoresson, Ann-Cathrin; Engstrand, Lars; Sandstedt, Bengt; Bernander, Sverker; Normark, Staffan

doi:10.1086/517365

Cited by 30 publications

(34 citation statements)

References 12 publications

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“…Consistent with this observation, there is variation among H. pylori isolates in the capacity to bind to Lewis b (7,16,23,28 …”

mentioning

confidence: 52%

“…Consistent with this observation, there is variation among H. pylori isolates in the capacity to bind to Lewis b (7,16,23,28). One study reported that 63 (66%) of 95 H. pylori isolates bound to Lewis b (16).…”

mentioning

confidence: 66%

“…In most previous studies, BabA protein expression has been detected indirectly, by using assays that test the capacity of H. pylori strains to bind to the Lewis b antigen (7,14,16,23,28). One recent study reported the generation of a polyclonal BabA antiserum (35), but experiments to evaluate the specificity of this antiserum were not presented.…”

Section: Discussionmentioning

confidence: 99%

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Heterogeneity amongHelicobacter pyloriStrains in Expression of the Outer Membrane Protein BabA

et al. 2004

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The BabA adhesin of Helicobacter pylori is an outer membrane protein that binds to the fucosylated Lewis b histo-blood group antigen on the surface of gastric epithelial cells. We screened a phage-displayed ScFv (single-chain fragment variable) recombinant antibody library for antibodies reactive with a recombinant BabA fragment and identified two such antibodies. Each antibody recognized an ϳ75-kDa protein present in wild-type H. pylori strain J99 but absent from an isogenic babA mutant strain. An immunoreactive BabA protein was detected by at least one of the antibodies in 18 (46%) of 39 different wild-type H. pylori strains and was detected more commonly in cagA-positive strains than in cagA-negative strains. Numerous amino acid polymorphisms were detected among BabA proteins expressed by different strains, with the greatest diversity occurring in the middle region of the proteins. Among the 18 strains that expressed a detectable BabA protein, there was considerable variation in the level of binding to Lewis b in vitro. Heterogeneity among H. pylori strains in expression of the BabA protein may be a factor that contributes to differing clinical outcomes among H. pylori-infected humans.Helicobacter pylori is a gram-negative bacterial organism that persistently colonizes the human gastric mucosa. Most H. pylori-infected humans tolerate the presence of this organism relatively well and never develop symptomatic gastroduodenal pathology. However, H. pylori infection is a risk factor for the development of peptic ulcer disease and distal gastric adenocarcinoma (8,11,27).Within the gastric mucosa, H. pylori lives within the mucus layer and may also attach to gastric epithelial cells. At least five different putative H. pylori adhesins (designated BabA, SabA, AlpA, AlpB, and HopZ) have been identified (16)(17)(18)(19). Of these, the BabA adhesin has been investigated in the most detail thus far. The H. pylori BabA adhesin mediates binding of H. pylori to the fucosylated Lewis b histo-blood group antigen present on the surface of gastric epithelial cells (5,16). In an animal model, Lewis b-dependent attachment of H. pylori to gastric epithelial cells is accompanied by increased severity of inflammation, development of parietal cell autoantibodies, and parietal cell loss (12, 15).There is a high level of genetic diversity among H. pylori isolates from different humans (4). Consistent with this observation, there is variation among H. pylori isolates in the capacity to bind to Lewis b (7,16,23,28 MATERIALS AND METHODSBacterial strains. H. pylori J99 and 26695 are reference strains for which the entire genome sequences are known (2, 29). An isogenic babA2 mutant derivative of H. pylori J99 was obtained from David Pride and Martin Blaser (23). The other strains utilized in the present study were isolated from patients in Denver, Colo., or Nashville, Tenn. The cagA and vacA genotypes of these strains have been reported previously (3,6,9,30). The term "cagA positive" indicates that cagA sequences are detectable by either ...

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“…Consistent with this observation, there is variation among H. pylori isolates in the capacity to bind to Lewis b (7,16,23,28 …”

mentioning

confidence: 52%

mentioning

confidence: 66%

Section: Discussionmentioning

confidence: 99%

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Heterogeneity amongHelicobacter pyloriStrains in Expression of the Outer Membrane Protein BabA

et al. 2004

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“…The finding that colonization with iceA2 strains is age correlated, being more common in older patients, has never been reported before. It could be related to age-dependent expression of host factors such as observed by Ç elik et al (8) for Le b receptors. iceA2 was more frequently found in males.…”

Section: Discussionmentioning

confidence: 77%

iceA Genotypes of Helicobacter pylori Strains Isolated from Brazilian Children and Adults

et al. 2001

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Data concerning the geographic distribution of iceA alleles are scarce, and information on the association of the gene with the disease is rare and still controversial. Furthermore, no such study has been developed in Brazil, where duodenal ulcer and gastric adenocarcinoma are very common. We investigated, by PCR, the frequency of iceA alleles and cagA status in Helicobacter pylori strains isolated from 142 patients (62 children and 80 adults; 66 female; mean age, 30.0 years; age range, 3 to 78 years) with gastritis, duodenal ulcer, or gastric adenocarcinoma. iceA was identified in bacterium samples obtained from all patients. Eleven (7.7%) of them were infected with multiple strains. Among the patients with nonmixed infection, iceA2 allele was detected in 118 (90.1%). iceA2 allele was associated with ulcer (P ‫؍‬ 0.02) and with carcinoma (P ‫؍‬ 0.001). iceA2 amplicons of 229, 334, or 549 bp were detected, but none of them was associated with the patient's disorder. iceA2 strains were more frequent in patients older than 7 years (P ‫؍‬ 0.001). The gene was also more frequent in strains obtained from males (P ‫؍‬ 0.02). cagA was more common in strains obtained from carcinoma (P ‫؍‬ 0.0008) and ulcer patients (P < 0.006). cagA-positive strains were more frequent in children older than 7 years (P < 0.003). No association between cagA status and sex was found (P ‫؍‬ 0.28). In conclusion, we think iceA should not be used as a reliable marker for predicting the clinical outcome of H. pylori infection.

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“…These authors demonstrated that bacterial adhesin to the Leb antigen is coded by the babA2 gene and is associated with the presence of the cagA gene. An interesting and surprising finding, demonstrated by Çelik et al [32] , is that children probably have few Leb receptors on surface mucous cells, which may explain the fact that susceptibility to colonization with a CagA-positive strain is linked to age.…”

Section: Discussionmentioning

confidence: 99%

Specific serum immunoglobulin G to H pylori and CagA in healthy children and adults (south-east of Iran)

Jafarzadeh¹,

Rezayati²,

Nemati³

2007

WJG

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AIM:To evaluate the serologic IgG response to H pylori and CagA across age groups and in healthy children and adults. METHODS:Totally, 386 children aged 1-15 years and 200 adults aged 20-60 years, were enrolled to study. The serum samples of participant were tested for presence of anti-H pylori and anti-CagA IgG by using ELISA method. RESULTS:The seroprevalence of H pylori in adults was significantly higher than that observed in children (67.5% vs 46.6%; P < 0.000003). In children, the seropositivity rate in males (51.9%) was significantly (P < 0.05) higher than that observed in females (41.7%). The prevalence of serum anti-CagA antibody was 72.8% and 67.4% in infected children and adults, respectively. The mean titer of serum anti-CagA antibodies was significantly higher among children in comparison to adults (64.1 Uarb/mL vs 30.7; P < 0.03). In infected children and adults the prevalence of serum anti-CagA antibody was higher in males compared to females (78.4% vs 66.3%; P = 0.07 and 75.6% vs 54.71%; P < 0.04, respectively). The age-specific prevalence of anti-H pylori and anti-CagA antibody (in infected subjects) was 37.6% and 59.57% at age 1-5 years, 46.9% and 75% at age 6-10 years, 54.9% and 79.45% at age 11-15, 59.01% and 83.33% at age 20-30 years, 66.6% and 60.52% at age 31-40 years, 73.46% and 63.88% at age 41-50 years and 75.75% and 60% at age 51-60 years with mean titer of anti-CagA antibody of 75.94, 63.32, 57.11, 52.06, 23.62, 21.52 and 21.80 Uarb/mL, respectively. There was significant difference between mean serum anti-CagA antibody in age subgroups (P < 0.001). CONCLUSION:These results showed that anti-H pylori and anti-CagA antibodies were common in the children and adults. The H pylori -specific antibodies influenced by age and sex of subjects. Moreover, it seems that males are more susceptible to infection with CagA + strains compared to females. The seroprevalence of anti-CagA antibody was increased with age, up to 30 years and then decreased. It was also found that the magnitude of the IgG response to CagA decreased with advanced age.

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Virulence and Colonization‐Associated Properties ofHelicobacter pyloriIsolated from Children and Adolescents

Cited by 30 publications

References 12 publications

Heterogeneity amongHelicobacter pyloriStrains in Expression of the Outer Membrane Protein BabA

Heterogeneity amongHelicobacter pyloriStrains in Expression of the Outer Membrane Protein BabA

iceA Genotypes of Helicobacter pylori Strains Isolated from Brazilian Children and Adults

Specific serum immunoglobulin G to H pylori and CagA in healthy children and adults (south-east of Iran)

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