Affinity purification of Helicobacter pylori urease. Relevance to gastric mucin adherence by urease protein

Synergistic effect of anti-Helicobacter pylori urease immunoglobulin Y from egg yolk of immunized hens and Lactobacillus johnsonii No.1088 to inhibit the growth of Helicobacter pylori in vitro and in vivo

Helicobacter pylori is a pathogenic bacterium that infects the stomach, causing chronic gastritis; and it is also considered to be related to the occurrence of gastric cancers. Although some eradication regimens including multiple antibiotics have been developed, the emergence of resistance to antibiotics becomes problematic. Therefore, other approaches to compensate or augment the effects of standard regimens are needed. In this study, we examined the possible synergistic effects of anti-H. pylori urease IgY and Lactobacillus johnsonii No.1088 (LJ88) both in vitro and in vivo. Anti-H. pylori urease IgY was purified from egg yolks laid by the hens immunized with urease purified from H. pylori. LJ88 is a unique strain of lactic acid bacterium isolated from human gastric juice, and it has been reported to inhibit H. pylori both in vitro and in vivo. The in vitro mixed culture study showed that anti-H. pylori urease IgY augmented the anti-H. pylori activity of LJ88 against both clarithromycin-sensitive and -resistant H. pylori strains. In a germ-free mice infection model, combined administration of daily anti-H. pylori urease IgY and weekly living LJ88 significantly reduced H. pylori infections, whereas either monotherapy did not. In an in vivo human gut microbiota-associated mice model, not only daily administration of living LJ88 but also heat-killed one significantly reduced an H. pylori infection in the stomach when combined with anti-H. pylori urease IgY. The extent of reduction of the stomach H. pylori by such a combination therapy was larger than that reported for LJ88 monotherapy. These results taken together revealed a synergistic effect of anti-H. pylori urease IgY and living or heat-killed LJ88, thus suggesting that such a combination might be a promising therapy to possibly compensate and/or augment standard anti-H. pylori regimens.

Ureases as multifunctional toxic proteins: A review

Ureases are metalloenzymes that hydrolyze urea into ammonia and carbon dioxide. They were the first enzymes to be crystallized and, with them, the notion that enzymes are proteins became accepted. Novel toxic properties of ureases that are independent of their enzyme activity have been discovered in the last three decades. Since our first description of the neurotoxic properties of canatoxin, an isoform of the jack bean urease, which appeared in Toxicon in 1981, about one hundred articles have been published on "new" properties of plant and microbial ureases. Here we review the present knowledge on the non-enzymatic properties of ureases. Plant ureases and microbial ureases are fungitoxic to filamentous fungi and yeasts by a mechanism involving fungal membrane permeabilization. Plant and at least some bacterial ureases have potent insecticidal effects. This entomotoxicity relies partly on an internal peptide released upon proteolysis of ingested urease by insect digestive enzymes. The intact protein and its derived peptide(s) are neurotoxic to insects and affect a number of other physiological functions, such as diuresis, muscle contraction and immunity. In mammal models some ureases are acutely neurotoxic upon injection, at least partially by enzyme-independent effects. For a long time bacterial ureases have been recognized as important virulence factors of diseases by urease-producing microorganisms. Ureases activate exocytosis in different mammalian cells recruiting eicosanoids and Ca(2+)-dependent pathways, even when their ureolytic activity is blocked by an irreversible inhibitor. Ureases are chemotactic factors recognized by neutrophils (and some bacteria), activating them and also platelets into a pro-inflammatory "status". Secretion-induction by ureases may play a role in fungal and bacterial diseases in humans and other animals. The now recognized "moonlighting" properties of these proteins have renewed interest in ureases for their biotechnological potential to improve plant defense against pests and as potential targets to ameliorate diseases due to pathogenic urease-producing microorganisms.

Growth inhibitory, bactericidal, and morphostructural effects of dehydrocostus lactone from Magnolia sieboldii Leaves on antibiotic-susceptible and -resistant strains of Helicobacter pylori

Helicobacter pylori is associated with various diseases of the upper gastrointestinal tract, such as gastric inflammation and duodenal and gastric ulcers. The aim of the study was to assess anti-H. pylori effects of the sesquiterpene lactone dehydrocostus lactone (DCL) from Magnolia sieboldii leaves, compared to commercial pure DCL, two previously known sesquiterpene lactones (costunolide and parthenolide), (-)-epigallocatechin gallate, and four antibiotics. The antibacterial activity of natural DCL toward antibiotic-susceptible H. pylori ATCC 700392 and H. pylori ATCC 700824 strains (MIC, 4.9 and 4.4 mg/L) was similar to that of commercial DCL and was more effective than costunolide, parthenolide, and EGCG. The activity of DCL was slightly lower than that of metronidazole (MIC, 1.10 and 1.07 mg/L). The antibacterial activity of DCL was virtually identical toward susceptible and resistant strains, even though resistance to amoxicillin (MIC, 11.1 mg/L for PED 503G strain), clarithromycin (49.8 mg/L for PED 3582GA strain), metronidazole (21.6 mg/L for H. pylori ATCC 43504 strain; 71.1 mg/L for 221 strain), or tetracycline (14.2 mg/L for B strain) was observed. This finding indicates that DCL and the antibiotics do not share a common mode of action. The bactericidal activity of DCL toward H. pylori ATCC 43504 was not affected by pH values examined (4.0-7.0). DCL caused considerable conversion to coccoid form (94 versus 49% at 8 and 4 mg/L of DCL for 48 h). The Western blot analysis revealed that urease subunits (UreA and UreB) of H. pylori ATCC 43504 were not affected by 10 mM of DCL, whereas UreA monomer band completely disappeared at 0.1 mM of (-)-epigallocatechin gallate. Global efforts to reduce the level of antibiotics justify further studies on M. sieboldii leaf-derived materials containing DCL as potential antibacterial products or a lead molecule for the prevention or eradication of drug-resistant H. pylori.

Anti-obesity activity of hen egg anti-lipase immunoglobulin yolk, a novel pancreatic lipase inhibitor

BACKGROUND

There is completely no report about both hen egg anti-lipase immunoglobulin yolk (IgY) and its anti-obesity action. Thus, we tried to isolate and characterize a novel anti-lipase immunoglobulin from hen egg yolk. Moreover, we investigated whether hen egg yolk anti-lipase IgY inhibits pancreatic lipase activity in vitro, and examined its ability to prevent obesity in a murine high fat diet-induced obesity model.

METHODS

We determined the inhibitory action of Anti-lipase IgY on lipase activity in vitro. We also focused our evaluation on the anti-obesity properties of Anti-lipase IgY in a murine high fat diet-induced obesity model.

RESULTS

Anti-lipase IgY blocked porcine lipase activity with an IC50 of 0.49 μM. Supplementing the high fat diet with only 0.2% (w/w) of Anti-lipase IgY for 35 days significantly decreased the weights of intraperitoneal adipose tissues, epididymal, mesenteric, retroperitoneal and perirenal adipose tissues, and the amounts of hepatic total lipid, triglyceride, and cholesterol. This was accompanied by a significant increase in the fecal excretion of triglyceride in the absence of diarrhea. Furthermore, Anti-lipase IgY treatment restored body weight gain to levels similar to mice fed with Control IgY.

CONCLUSIONS

This study provides the first report of the development of anti-lipase IgY and the direct evidence that inhibition of pancreatic lipase using Anti-lipase IgY is an effective anti-obesity treatment due to the associated increase in fecal excretion of triglyceride.

Growth-inhibiting, bactericidal, and urease inhibitory effects of Paeonia lactiflora root constituents and related compounds on antibiotic-susceptible and -resistant strains of Helicobacter pylori

An assessment was made of the growth-inhibiting, bactericidal, and urease inhibitory activities of paeonol (PA), benzoic acid (BA), methyl gallate (MG), and 1,2,3,4,6-penta-O-galloyl-β-d-glucopyranose (PGG) identified in Paeonia lactiflora root, structurally related compounds, and four antibiotics toward three reference strains and four clinical isolates of Helicobacter pylori using broth dilution bioassay and Western blot. BA and PA showed strong bactericidal effect at pH 4, while MG and PGG were effective at pH 7. These constituents exhibited strong growth-inhibiting and bactericidal activity toward the five strains resistant to amoxicillin (minimal inhibitory concentration (MIC) 12.5 mg/L), clarithromycin (64 mg/L), metronidazole (64 mg/L), or tetracycline (15 mg/L), indicating that these constituents and the antibiotics do not share a common mode of action. Structural characteristics, such as types of functional groups and carbon skeleton, and hydrophobicity appear to play a role in determining the anti- H. pylori activity. H. pylori urease inhibitory activity of PGG was comparable to that of acetohydroxamic acid, while MG was less potent at inhibiting urease than thiourea. The UreB band disappeared at 250 mg/L PGG on Western blot, while the UreA bands were faintly visible at 1000 mg/L PGG. These constituents showed no significant cytotoxicity. Global efforts to reduce the level of antibiotics justify further studies on P. lactiflora root-derived materials containing MG, PA, and PGG as potential antibacterial products or lead molecules for the prevention or eradication from humans from diseases caused by H. pylori .

Peptides from Pisum sativum L. enzymatic protein digest with anti-adhesive activity against Helicobacter pylori: structure-activity and inhibitory activity against BabA, SabA, HpaA and a fibronectin-binding adhesin

SCOPE

Identification of anti-adhesive peptides against Helicobacter pylori obtained by enzymatic hydrolysis of seed proteins from Pisum sativum L. (Fabaceae).

METHODS AND RESULTS

Bioassay-guided fractionation of protein tryptic digest by ultrafiltration, size exclusion chromatography (SEC) and reversed phase chromatography (RPC) were used. Identification of bioactive peptides was achieved by MALDI-TOF-MS. Adhesion of H. pylori was monitored by two different assays, using a quantitative in vitro assay on human AGS cells with evaluation of bacterial binding by flow cytometry, beside a semi-quantitative in situ adhesion assay using FITC-labelled H. pylori on human stomach tissue sections. From two highly active fractions (F3, F3.3) two anti-adhesive peptides (S3, S5) were identified. Neither F3 nor S3 or S5 had any cytotoxic effect against H. pylori. By hemagglutination assay and semiquantitative dot blot overlay assay with immobilized ligands it was shown that F3 interacts specifically with H. pylori adhesins BabA, SabA, HpaA and a fibronectin-binding adhesin, while S3 and S5 inhibit only BabA. It was demonstrated that BabA, usually interacting with carbohydrate motifs such as fucosylated blood group antigens, interacts with the peptide moieties.

CONCLUSION

Bioactive peptides from pea protein could be applied as functional ingredients for protecting infants and children against infections such as H. pylori.

Large molecules as anti-adhesive compounds against pathogens

Anti-adhesive compounds are potential prophylactic tools in alternative treatment regimes against bacterial infection, as bacterial adhesion is commonly mediated by carbohydrate-protein interactions between surface adhesions of microorganisms and the host cell. The use of exogenous polyvalent, high-molecular carbohydrates and tannin-like plant-derived compounds should antagonize the adhesive interaction. A range of carbohydrates and carbohydrate- and proanthocyanidin-enriched plant extracts were screened for potential anti-adhesive effects against Helicobacter pylori, Campylobacter jejuni, Porphyromonas gingivalis and Candida albicans in different in-situ assays on primary tissue. The adhesion of H. pylori on human stomach tissue was effectively blocked by glucuronic acid-enriched polysaccharides from immature okra fruits (Abelmoschus esculentus). These compounds also had strong in-vitro effects against C. jejuni (inhibition up to 80%), but were ineffective in an in-vivo study in infected chicken broilers due to metabolism in the gastrointestinal system. Polysaccharides from Glycyrrhizia glabra, also enriched with glucuronic acid, showed strong anti-adhesive properties against H. pylori and P. gingivalis (inhibition 60–70%). Pelargonium sidoides extract, containing mainly polymeric proanthocyanidins, was effective against H. pylori in a dose-dependent manner. Due to the multifunctional adhesive strategy of C. albicans, no effective compounds were detected against this yeast. Structure-activity relationships are presented and the potential in-vivo use of carbohydrate-based anti-adhesives is discussed.

Antiadhesive property of microalgal polysaccharide extract on the binding of Helicobacter pylori to gastric mucin

The emergence of antibiotic-resistant Helicobacter pylori is of concern in the treatment of H. pylori-associated gastroduodenal diseases. As the organism was reported to bind gastric mucin, we used porcine gastric mucin as substrate to assess the antiadhesive property of polysaccharides derived from Spirulina (PS), a commercially available microalga, against the binding of H. pylori to gastric mucin. Results show that polysaccharides prevented H. pylori from binding to gastric mucin optimally at pH 2.0, without affecting the viability of either bacteria or gastric epithelial cells, thus favouring its antiadhesive action in a gastric environment. Using ligand overlay analysis, polysaccharide was demonstrated to bind H. pylori alkyl hydroperoxide reductase (AhpC) and urease, which have shown here to possess mucin-binding activity. An in vivo study demonstrated that bacteria load was reduced by >90% in BALB/c mice treated with either Spirulina or polysaccharides. It is thus suggested that polysaccharides may function as a potential antiadhesive agent against H. pylori colonization of gastric mucin.

Implications for induction of autoimmunity via activation of B-1 cells by Helicobacter pylori urease

Besides various gastroduodenal diseases, Helicobacter pylori infection may be involved in autoimmune disorders like rheumatoid arthritis (RA) or idiopathic thrombocytopenic purpura. Such autoimmune disorders are often associated with autoreactive antibodies produced by B-1 cells, a subpopulation of B lymphocytes. These B-1 cells are mainly located in the pleural cavity or mucosal compartment. The existence of H. pylori urease-specific immunoglobulin A (IgA)-producing B cells in the mucosal compartment and of their specific IgM in the sera of acutely infected volunteers suggests the possibility that urease stimulates mucosal innate immune responses. Here, we show for the first time that purified H. pylori urease predominantly stimulates the B-1-cell population rather than B-2 cells, which produce antigen-specific conventional antibodies among splenic B220(+) B cells. The fact that such stimulation of B-1 cells was not affected by the addition of polymyxin B indicates that the effect of purified H. pylori urease was not due to the contamination with bacterial lipopolysaccharide. Furthermore, the production of various B-1-cell-related autoreactive antibodies such as IgM-type rheumatoid factor, anti-single-stranded DNA antibody, and anti-phosphatidyl choline antibody was observed when the splenic B cells were stimulated with purified H. pylori urease in vitro. These findings suggest that H. pylori components, urease in particular, may be among the environmental triggers that initiate various autoimmune diseases via producing autoreactive antibodies through the activation of B-1 cells. The findings shown here offer important new insights into the pathogenesis of autoimmune disorders related to H. pylori infection.

Suppressive effect of functional drinking yogurt containing specific egg yolk immunoglobulin on Helicobacter pylori in humans

Helicobacter pylori is a human pathogen that infects over 50% of the population worldwide. It is the most important etiologic agent of gastroduodenal ulcers and malignancies. Helicobacter pylori urease enzyme is considered the main factor for the organism's colonization in the gastroduodenal mucosa. Hens immunized with the purified urease produce a highly specific anti-H. pylori urease immunoglobulin (IgY-urease) in their egg yolks. Immunoglobulin Y-urease was stable at 60 to 65 degrees C for 30 min and at pH 4.0 for 7 h. Its activity was lost at 80 degrees C for 20 min and at pH 2 for 4 h. Specially designed functional drinking yogurt containing Lactobacillus acidophilus and Bifidobacterium spp. with 1% egg yolk IgY-urease was produced commercially. Immunoglobulin Y-urease activity showed stability in the product up to 7 d, and then decreased to 85% after 3 wk of storage. A clinical study was conducted to determine the effectiveness of IgY-urease yogurt to suppress infection in humans. Forty-two volunteers who tested positive for H. pylori using a 13C-urea breath test were recruited. A total of 450 mL of IgY-urease (test group) or IgY-urease-free yogurt (control group) was consumed in 150-mL portions 3 times daily for 4 wk. Volunteers were tested after 2 and 4 wk; urea breath test values significantly decreased in the test group compared with the control group. The results indicate that suppression of H. pylori infection in humans could be achieved by consumption of drinking yogurt fortified with IgY-urease.

Effect of dietary anti-urease immunoglobulin Y on Helicobacter pylori infection in Mongolian gerbils

BACKGROUND AND AIM

Helicobacter pylori is known to be a major pathogenic factor in the development of gastritis, peptic ulcer disease and gastric cancer. Recently, chicken egg yolk immunoglobulin Y (IgY) has been recognized as an inexpensive antibody source for passive immunization against gastrointestinal infections. The present study was designed to investigate the effect of anti-urease IgY on H. pylori infection in Mongolian gerbils.

METHODS

H. pylori-infected Mongolian gerbils were administered a diet containing anti-urease IgY, with or without famotidine (F). After 10 weeks, bacterial culture and measurement of the gastric mucosal myeloperoxidase (MPO) activity were performed. In a second experiment, another group of gerbils was started on a diet containing F + IgY a week prior to H. pylori inoculation. After 9 weeks, these animals were examined.

RESULTS

In the H. pylori-infected gerbils, there were no significant differences in the level of H. pylori colonization among the different dietary and control groups. However, the MPO activity was significantly decreased in the H. pylori group administered the F + IgY diet compared with that in the H. pylori group administered the IgY, F, or control diet. Furthermore, in the gerbils administered the F + IgY diet prior to the bacterial inoculation, inhibition of H. pylori colonization and suppression of the elevated gastric mucosal MPO activity were observed.

CONCLUSIONS

Oral administration of urease-specific IgY not only inhibited H. pylori disease activity in H. pylori-infected gerbils, but also prevented H. pylori colonization in those not yet infected. These encouraging results may pave the way for a novel therapeutic and prophylactic approach in the management of H. pylori-associated gastroduodenal disease.

Melanoidin, a food protein-derived advanced maillard reaction product, suppresses Helicobacter pylori in vitro and in vivo

BACKGROUND

Extracellular urease proteins located on the surface of Helicobacter pylori are gastric mucin-targeted adhesins, which play an important role in infection and colonization to the host. In this study we have determined the inhibitory activity of a variety of melanoidins, protein-derived advanced Maillard reaction products, ubiquitously found in heat-treated foods, on urease-gastric mucin adhesion. In addition, we have determined the anticolonization effect of melanoidin I, prepared by the Maillard reaction between casein and lactose, in an animal model and in human subjects infected with this bacterium.

METHODS

The inhibitory activity of each compound was determined by a competitive binding assay of labeled gastric mucin to plate-immobilized urease. Melanoidin I was used in an in vivo trial using euthymic hairless mice as an infection model. Melanoidin I was consumed for 8 weeks by subjects infected with H. pylori. The [(13)C] urease breath test and H. pylori-specific antigen in the stool (HpSA) test were performed on subjects at week 0 and week 8.

RESULTS

A variety of food protein-derived melanoidins strongly inhibited urease-gastric mucin adhesion in the concentration range of 10 micro g/ml to 100 micro g/ml. In particular, melanoidin I significantly (p <.05) suppressed colonization of H. pylori in mice when given for 10 weeks via the diets. Eight weeks daily intake of 3 g melanoidin I significantly (p <.05) decreased the optical density of HpSA in subjects.

CONCLUSION

Foods containing protein-derived melanoidins may be an alternative to antibiotic-based therapy to prevent H. pylori that combines safety, ease of administration and efficacy.

Effect of dietary anti-Helicobacter pylori-urease immunoglobulin Y on Helicobacter pylori infection

Recently, chicken egg yolk was recognized as an inexpensive antibody source, and the therapeutic usefulness of egg yolk immunoglobulin Y (IgY) in oral passive immunization has been investigated. Although multiple antibiotic treatments eradicate most Helicobacter pylori (H. pylori) infections, therapy fails in 10-15% of cases due to the development of drug resistance. Consequently, it is important that new, more broadly based therapies for the treatment of H. pylori infection should be identified. The present study evaluated the effect, on H. pylori infection, of IgY prepared from egg yolk of hens immunized with H. pylori urease (anti-HpU IgY). Seventeen asymptomatic volunteers diagnosed as H. pylori-positive by the 13C-urea breath test (UBT) were orally administered anti-HpU IgY for 4 weeks. Four weeks later, UBT values were significantly decreased although no case showed H. pylori eradication. An H. pylori-positive 53-year-old female gastritis patient administered anti-HpU IgY plus lansoprazole for 8 weeks showed a decrease in serum pepsinogen (PG) I and UBT values as well as an increase in the PG I/II ratio. In conclusion, anti-HpU IgY may mitigate H. pylori-associated gastritis and partially attenuate gastric urease activity. Furthermore, anti-HpU IgY combined with antacids appears to ameliorate gastric inflammation. These encouraging results may represent a novel approach to the management of H. pylori-associated gastroduodenal disease.

Surface localized glyceraldehyde-3-phosphate dehydrogenase of Mycoplasma genitalium binds mucin

Mycoplasma genitalium is the smallest known self-replicating cell. It was first isolated from urethral specimens in individuals with non-gonococcal urethritis and, more recently, from respiratory and synovial sites. Our laboratory has been interested in defining the mechanisms by which M. genitalium adheres to and colonizes host cell surfaces. In order to determine potential targets of adherence, we examined the interaction of M. genitalium with a primary component of the mucosal epithelial lining, mucin (Mn). Three Mn-binding proteins (MnBPs) of M. genitalium were isolated by affinity chromatography. One of these proteins was identified by N-terminal sequencing as glyceraldehyde-3-phosphate dehy-drogenase (GAPDH). Antiserum raised against recombinant GAPDH blocked binding of intact biosynthetically labelled mycoplasmas to mucin by approximately 70%. Whole cell radioimmunoprecipitation indicated that GAPDH was surface-accessible and surface localization of GAPDH was further verified by membrane fractionation and immunoelectron microscopy. The role of GAPDH as an adhesin to Mn not only provides insights into the organism's mechanisms of adherence and colonization but also into its ability to maximize its limited genome.

Adherence protects the binding sites of Helicobacter pylori urease from acid-induced damage

Colonization by Helicobacter pylori partly depends on acid-dependent adherence by urease to gastric mucin. To further verify the relevance of urease adherence to colonization, the influence of acidity on the binding sites of H. pylori urease was investigated. When enzyme-based in vitro ligand capture assays were used, the effect of acidity on the binding site of H. pylori urease was determined against a backdrop medium consisting of acidic buffers simulating the luminal side of gastric mucus. A high degree of stability was exhibited by adherent urease, suggesting a pivotal role by the denatured enzyme in the persistence of the bacterium within the acidified compartment of gastric mucus.

Enhanced reduction of Helicobacter pylori load in precolonized mice treated with combined famotidine and urease-binding polysaccharides

The present study investigated the effect of a model urease-binding polysaccharide in combination with a histamine H(2) receptor antagonist on Helicobacter pylori colonization in vivo. Euthymic hairless mice were treated daily with dextran sulfate via drinking water and/or famotidine via intragastric gavage starting at 1 week postchallenge with a CagA(+) VacA(+) (type 1) strain of H. pylori. Treatment of precolonized mice for 2 weeks with dextran sulfate combined with famotidine yielded a group mean bacterial load (per 100 mg of gastric tissue) of log(10) 1.04 CFU, which was significantly lower than those of the famotidine (log(10) 3.35 CFU, P < 0.01) and dextran sulfate (log(10) 2.45 CFU, P < 0.05) monotherapy groups and the infected nontreated group (log(10) 3.64 CFU, P < 0.01). Eradication was achieved after 2 weeks of treatment in 50% or more of the test mice using drug combinations (1 or 2 weeks of famotidine plus 2 weeks of dextran sulfate) versus none in the monotherapy and positive control groups. The enhanced activity of the drug combination may be related to the daily pattern of transient acid suppression by famotidine inducing periodic bacterial convergence to superficial mucus sites penetrated by dextran sulfate from the lumen. Increased urease-dextran sulfate avidity was observed in vitro in the presence of famotidine and may partly account for the enhanced activity. With potential utility in abbreviating treatment time and eradication of antibiotic-resistant strains, the use of urease-targeted polysaccharides concurrently with a gastric acid inhibitor warrants consideration as an additional component of the standard multidrug chemotherapy of H. pylori infection.

Acid-dependent adherence of Helicobacter pylori urease to diverse polysaccharides

BACKGROUND & AIMS

The significance of acid-primed recognition of ligands by Helicobacter pylori urease is unknown. This study aimed to further characterize the specificity of urease adherence in vitro and verify whether specific inhibition will translate into in vivo suppression of colonization.

METHODS

A highly sensitive competitive enzyme-linked ligand capture assay was used to quantify the capacity of each test inhibitor to compete with labeled mucin for binding sites on immobilized native urease. A model polymer that strongly bound urease was used in an in vivo trial using euthymic hairless mice as an infection model.

RESULTS

The blockage of urease-gastric mucin interaction by certain inhibitors revealed an acid-functional lectin-like activity by urease, specifically recognizing bacterial lipopolysaccharides and certain species of polysaccharides, nonbacterial glycolipids, and glycoproteins. Dextran sulfate significantly (P < 0.01) suppressed colonization of mice by H. pylori when given before and/or after challenge.

CONCLUSIONS

The acid-driven high-affinity adherence of H. pylori urease to mucin and lipopolysaccharides contributes to gastric mucosal colonization by the bacterium based on in vivo targeting experiments using specific polysaccharides in a mouse model with acute infection. Acid-functional urease-homing polysaccharides that can interfere with urease-mucin or H. pylori whole cell-mucin interaction in vitro can significantly interfere with colonization by the bacterium in vivo.