| 1. |
- Aspholm, Marina, et al.
(författare)
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SabA is the H. pylori hemagglutinin and is polymorphic in binding to sialylated glycans.
- 2006
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Ingår i: PLoS pathogens. - : Public Library of Science (PLoS). - 1553-7374 .- 1553-7366. ; 2:10
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Tidskriftsartikel (refereegranskat)abstract
- Adherence of Helicobacter pylori to inflamed gastric mucosa is dependent on the sialic acid-binding adhesin (SabA) and cognate sialylated/fucosylated glycans on the host cell surface. By in situ hybridization, H. pylori bacteria were observed in close association with erythrocytes in capillaries and post-capillary venules of the lamina propria of gastric mucosa in both infected humans and Rhesus monkeys. In vivo adherence of H. pylori to erythrocytes may require molecular mechanisms similar to the sialic acid-dependent in vitro agglutination of erythrocytes (i.e., sialic acid-dependent hemagglutination). In this context, the SabA adhesin was identified as the sialic acid-dependent hemagglutinin based on sialidase-sensitive hemagglutination, binding assays with sialylated glycoconjugates, and analysis of a series of isogenic sabA deletion mutants. The topographic presentation of binding sites for SabA on the erythrocyte membrane was mapped to gangliosides with extended core chains. However, receptor mapping revealed that the NeuAcalpha2-3Gal-disaccharide constitutes the minimal sialylated binding epitope required for SabA binding. Furthermore, clinical isolates demonstrated polymorphism in sialyl binding and complementation analysis of sabA mutants demonstrated that polymorphism in sialyl binding is an inherent property of the SabA protein itself. Gastric inflammation is associated with periodic changes in the composition of mucosal sialylation patterns. We suggest that dynamic adaptation in sialyl-binding properties during persistent infection specializes H. pylori both for individual variation in mucosal glycosylation and tropism for local areas of inflamed and/or dysplastic tissue.
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| 2. |
- Mahdavi, Jafar, et al.
(författare)
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Helicobacter pylori SabA adhesin in persistent infection and chronic inflammation
- 2002
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Ingår i: Science. - : American Association for the Advancement of Science. - 0036-8075 .- 1095-9203. ; 297:5581, s. 573-578
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Tidskriftsartikel (refereegranskat)abstract
- Helicobacter pylori adherence in the human gastric mucosa involves specific bacterial adhesins and cognate host receptors. Here, we identify sialyl-dimeric-Lewis x glycosphingolipid as a receptor for H. pylori and show that H. pylori infection induced formation of sialyl-Lewis x antigens in gastric epithelium in humans and in a Rhesus monkey. The corresponding sialic acid-binding adhesin (SabA) was isolated with the "retagging" method, and the underlying sabA gene (JHP662/HP0725) was identified. The ability of many H. pylori strains to adhere to sialylated glycoconjugates expressed during chronic inflammation might thus contribute to virulence and the extraordinary chronicity of H. pylori infection.
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| 3. |
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| 4. |
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| 5. |
- Petersson, Christoffer, 1973-, et al.
(författare)
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Helicobacter pylori sabA adhesin evokes a strong inflammatory response in human neutrophils which is down-regulated by the neutrophil-activating protein
- 2006
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Ingår i: Medical Microbiology and Immmunology. - : Springer Science and Business Media LLC. - 0300-8584 .- 1432-1831. ; 195:4, s. 195-206
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Tidskriftsartikel (refereegranskat)abstract
- The human pathogen Helicobacter pylori expresses two dominant adhesins; the Lewis b blood group antigen binding adhesin, BabA, and the sialic acid-binding adhesin, SabA. These adhesins recognize specific carbohydrate moieties of the gastric epithelium, i.e. the Lewis b antigen, Leb, and the sialyl-Lewis x antigen, sLex, respectively, which promote infection and inflammatory processes in the gastroduodenal tract. To assess the contribution of each of BabA, SabA and the neutrophil activating protein (HP-NAP) in a local inflammation, we investigated the traits of H. pylori mutants in their capacity to interact with and stimulate human neutrophils. We thence found that the SabA adhesin was not only the key inducer of oxidative metabolism (Unemo et al. J Biol Chem 280:15390–15397, 2005), but also essential in phagocytosis induction, as evaluated by flow cytometry, fluorescence microscopy and luminol-enhanced chemiluminescence. The napA deletion resulted in enhanced generation of reactive oxygen species and impaired adherence to the host cells. In conclusion, the SabA adhesin stimulates human neutrophils through selectin-mimicry. Interestingly, HP-NAP modulates the oxidative burst, which could tune the impact of the H. pylori infection for establishment of balanced and chronic inflammation of the gastric mucosa.
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