DNA-Level Characterization of<i>Helicobacter pylori</i>Strains from Patients with Overt Disease and with Benign Infections in Bangladesh

Rahman, Motiur; Mukhopadhyay, Asish K.; Nahar, Shamsun; Datta, Simanti; Ahmad, Milan Mashhud; Sarker, Safique; Mas’ud, Ibrahim; Engstrand, Lars; Albert, M. John; Nair, G. Balakrish; Berg, Douglas E.

doi:10.1128/jcm.41.5.2008-2014.2003

Cited by 35 publications

(24 citation statements)

References 34 publications

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“…In addition, genetic differences in both the infecting strains and in their hosts in Bangladesh and Sweden also have a potential to influence the immune response. Although previous studies indicate that CagA is expressed by a majority of strains isolated from both Bangladeshi and Swedish individuals (Hamlet et al , 1999; Rahman et al , 2003), it is likely that more significant differences exist in the expression of other virulence factors. Our results nevertheless suggest that differences in bacterial and host genetics, H. pylori acquisition pattern, exposure to other gastroenteric pathogens or socioeconomical background factors may have relatively limited effects on the immune responses locally in the stomach.…”

Section: Discussionmentioning

confidence: 94%

Comparison of mucosal B- and T-cell responses inHelicobacter pylori-infected subjects in a developing and a developed country

Bhuiyan¹,

Qadri²,

Bardhan³

et al. 2008

FEMS Immunology &Amp; Medical Microbiology

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Helicobacter pylori is highly endemic in developing countries, but comparatively little is known about mucosal immune responses to H. pylori in these settings. Therefore, we have compared B- and T-cell responses, with a focus on the gastrointestinal mucosa, in H. pylori-infected adults in a developing (Bangladesh) and a developed (Sweden) country. We found comparable numbers of CD19(+) B cells and CD4 (+)T cells and similar levels of H. pylori-specific IgA antibodies in gastric mucosa from Bangladeshi and Swedish volunteers. However, about threefold higher numbers of CD19(+) B cells and 12-fold increased levels of H. pylori-specific IgA antibodies were found in the duodenum of Bangladeshi subjects. The gastric and duodenal immune responses in Bangladeshi asymptomatic carriers and duodenal ulcer patients were comparable. Bangladeshi subjects had about twofold lower titers of H. pylori-specific IgA and IgG antibodies in the circulation compared with Swedish volunteers. In conclusion, our findings suggest that Bangladeshi individuals have comparable gastric immune responses, but lower systemic antibody responses to H. pylori, compared with Swedish volunteers. Increased inflammation is present in the duodenum of Bangladeshi volunteers, maybe as a result of frequent exposure to enteric infections in these individuals.

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Section: Discussionmentioning

confidence: 94%

Comparison of mucosal B- and T-cell responses inHelicobacter pylori-infected subjects in a developing and a developed country

Bhuiyan¹,

Qadri²,

Bardhan³

et al. 2008

FEMS Immunology &Amp; Medical Microbiology

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“…The sequence diversities at the 5'-end of the cagA gene and the mid-region alleles of the vacA gene have been used to deduce the genetic relationships among strains from East Asia, South Asia, South America, Africa, Europe and USA [8,9]. However, there are no data on the genetic affinity of Arab strains from the Arabian Gulf Region including those from Kuwait, although some data exist on their genotypes [10,11].…”

Section: Resultsmentioning

confidence: 99%

Genetic affinities of Helicobacter pylori isolates from ethnic Arabs in Kuwait

et al. 2010

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Helicobacter pylori is one of the most genetically diverse of bacterial species, and since the 5'-end of cagA gene and the middle allele of vacA gene of H. pylori from different populations exhibit considerable polymorphisms, these sequence diversities were used to gain insights into the genetic affinities of this gastric pathogen from different populations. Because the genetic affinity of Arab strains from the Arabian Gulf is not known, we carried out genetic analysis based on sequence diversities of the cagA and the vacA genes of H. pylori from 9 ethnic Arabs in Kuwait. The analysis showed that the Kuwaiti isolates are closely related to the Indo-European group of strains, although some strains have a tendency to form a separate cluster close to the Indo- European group, but clearly distinct from East Asian strains. However, these results need to be confirmed by analyses of neutral markers (house-keeping genes in a multi-locus sequence typing [MLST]) platform. The profiling of virulence-associated genes may have resulted from ecologically distinct populations due to human migration and geographical separation over long periods of time.

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“…The Hel 305 strain was originally isolated from a Swedish duodenal ulcer patient and carries an intact Cag pathogenicity island and expresses VacA s1/m1 This genotype is also common in Bangladeshi H. pylori strains [23]. Western blot analysis showed that the Hel 305 MP contains many different proteins, including urease, NAP, HpaA and flagellin, as well as LPS (<50% wt/wt).…”

Section: Methodsmentioning

confidence: 99%

Th1 and Th17 Responses to Helicobacter pylori in Bangladeshi Infants, Children and Adults

et al. 2014

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Both Th1 and Th17 cells are important components of the immune response to Helicobacter pylori (Hp) in adults, but less is known about T cell responses to Hp during early childhood, when the infection is often acquired. We investigated Th1 and Th17 type responses to Hp in adults, children and infants in Bangladesh, where Hp is highly endemic. IL-17 and IFN-γ mRNA levels in gastric biopsies from Hp-infected Bangladeshi adults were analyzed and compared to levels in infected and uninfected Swedish controls. Since biopsies could not be collected from infants and children, cytokine responses in Bangladeshi infants (6–12 months), children (3–5 years) and adults (>19 years) were instead compared by stimulating peripheral blood mononuclear cells (PBMCs) with a Hp membrane preparation (MP) and analyzing culture supernatants by ELISA and cytometric bead array. We found significantly higher expression of IL-17 and IFN-γ mRNA in gastric mucosa of Hp-infected Bangladeshi and Swedish adults compared to uninfected Swedish controls. PBMCs from all age groups produced IL-17 and IFN-γ after MP stimulation, but little Th2 cytokines. IL-17 and IFN-γ were primarily produced by CD4+ T cells, since CD4+ T cell depleted PBMCs produced reduced amounts of these cytokines. Infant cells produced significantly more IL-17, but similar levels of IFN-γ, compared to adult cells after MP stimulation. In contrast, polyclonal stimulation induced lower levels IL-17 and IFN-γ in infant compared to adult PBMCs and CD4+ T cells. The strong IL-17 production in infants after MP stimulation was paralleled by significantly higher production of the IL-17 promoting cytokine IL-1β from infant compared to adult PBMCs and monocytes. In conclusion, these results show that T cells can produce high levels of IL-17 and IFN-γ in response to Hp from an early age and indicate a potential role for IL-1β in promoting Th17 responses to Hp during infancy.

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DNA-Level Characterization ofHelicobacter pyloriStrains from Patients with Overt Disease and with Benign Infections in Bangladesh

Cited by 35 publications

References 34 publications

Comparison of mucosal B- and T-cell responses inHelicobacter pylori-infected subjects in a developing and a developed country

Comparison of mucosal B- and T-cell responses inHelicobacter pylori-infected subjects in a developing and a developed country

Genetic affinities of Helicobacter pylori isolates from ethnic Arabs in Kuwait

Th1 and Th17 Responses to Helicobacter pylori in Bangladeshi Infants, Children and Adults

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