Katsushi Watanabe

Immune responses in mice to intranasal and intracutaneous administration of a DNA vaccine encoding Helicobacter pylori-catalase

We previously reported that the intracutaneous injection of DNA vaccines encoding Helicobacter pylori heat shock proteins elicited specific immune responses, and led to reduced infection in mice. In this study, we constructed DNA vaccine encoding H. pylori-catalase (pcDNA3.1-kat) and investigated the immune responses to intranasal and intracutaneous administration of pcDNA3.1-kat. C57/BL6 mice were immunized intracutaneously with 10 microg of pcDNA3.1-kat or intranasally with 50 microg of pcDNA3.1-kat. Catalase-specific IgG antibody was detected in the sera of intranasal and intracutaneous immunized mice. Both intranasal and intracutaneous immunized mice were significantly protected from colonization by H. pylori and had significantly reduced degrees of gastritis. These results demonstrate that DNA vaccine encoding H. pylori-catalase can induce an immune response against H. pylori, and that intranasal immunization works as well as intracutaneous immunization.

Helicobacter pylori-Stimulated Interleukin-8 (IL-8) Promotes Cell Proliferation Through Transactivation of Epidermal Growth Factor Receptor (EGFR) by Disintegrin and Metalloproteinase (ADAM) Activation

Helicobacter pylori infection increases the risk of hyperplastic polyps and gastric cancer, but the mechanisms remain to be elucidated. H. pylori was recently shown to transactivate epidermal growth factor receptor (EGFR) through metalloprotease stimulation. The present study was designed to investigate the effect of interleukin-8 (IL-8) induced by H. pylori infection on EGFR transactivation and epithelial cell growth. H. pylori Sydney strain 1 (SS1) having wild-type cag+A was used. Phospho-EGFR assay was performed by immunoprecipitation using anti-human EGFR and anti-phosphotyrosine antibodies. DNA synthesis was evaluated by [3H]thymidine uptake using the human gastric cancer cell line, KATO III. H. pylori induced EGFR phosphorylation, and a disintegrin and metalloproteinase (ADAM) inhibitor, KB-R7785, completely suppressed EGFR phosphorylation. IL-8 also induced EGFR phosphorylation, while anti-IL-8 and anti-IL-8 receptor (CXCR1) neutralizing antibodies suppressed EGFR phosphorylation. [3H]Thymidine uptake analysis demonstrated that H. pylori increased DNA synthesis in gastric epithelial cells, and tyrosine kinase inhibitor, MEK inhibitor, and ADAM inhibitor suppressed the DNA synthesis induced by H. pylori. H. pylori-stimulated IL-8 accelerates processing of EGFR ligands through ADAM activation, and cleaved EGFR ligands bind and stimulate EGFR in paracrine and autocrine manners to induce cell proliferation. This may be one of the mechanisms of hyperplastic polyp and gastric cancer development in H. pylori-infected gastric mucosa.

Oral Vaccination Against Helicobacter pylori with Recombinant Cholera Toxin B‐Subunit

Background.  The innocuous pure recombinant cholera toxin B‐subunit (rCTB) is very attractive as a strong adjuvant for host immunization, but little is known about rCTBs gastric mucosal immunoadjuvanticity against Helicobacter pylori. The immunoadjuvanticity of rCTB against H. pylori was tested.

Development and clinical application of an immunoassay using intact Helicobacter pylori attached to a solid phase as an antigen

OBJECTIVE At present, H. pylori homogenates, extracts and recombinant proteins are used as antigens in immunoassays, but significant false positive and negative results are obtained. We attempted to develop an ELISA system using immobilized whole intact H. pylori cells as a solid phase antigen (WIC-ELISA) which specifically recognizes surface antigens. METHODS Intact H. pylori cells were immobilized on ELISA plates by centrifugation (150 g for 10 min). HRP-labeled antihuman IgG was used as the second antibody. H. pylori-infections were investigated with WIC-ELISA and a conventional method in which H. pylori-extracts were used as antigen in 117 patients. RESULTS WIC-ELISA showed better characteristics than conventional ELISA in regards to sensitivity (98.9 vs. 90.4%), specificity (95.7 vs. 95.7%), positive predictive value (98.9 vs. 98.8%), negative predictive value (95.7 vs. 71.0%) and accuracy (98.3 vs. 91.5%). CONCLUSIONS WIC-ELISA is useful for quantification of antibodies against H. pylori surface antigens and as a clinical screening test.

Severe Henoch-Schonlein Purpura with Intestinal Hemorrhagic Ulcers : Treated by Steroid Pulse Therapy : Case Reports

Abstract: Henoch‐Schönlein purpura, associated with severe duodenal hemorrhage and gastrointestinal dysfunction, was dramatically suppressed by steroid pulse therapy. A 22‐year‐old male was admitted with abdominal pain, purpuric rash, and neutrophilic leukocytosis. C‐reactive protein was increased and coagulation Factor XIII was markedly decreased. Upper gastrointestinal endoscopy disclosed multiple ulcers and erythema with petechiae in the postbulbar duodenum. Based on laboratory findings including examination of a skin biopsy specimen, this patient was diagnosed as having Henoch‐Schönlein purpura. Despite aggressive administration of prednisolone, intravenous hyperalimentation, and Factor XIII concentrate, symptoms worsened. Steroid pulse therapy was then given for three days, resulting in amelioration of all clinical findings. The duodenal ulcers showed scarring on endoscopy. Gastrointestinal complications of Henoch‐Schönlein purpura. Factor XIII concentrate therapy, and pulse steroid therapy are discussed herein.

Increased serum pepsinogen-I level predicts development of new duodenal erosion following eradication teraphy of H.pylori

Aims: Eradication of Helicobacter pylori (Hp) decreases the concentrations of serum gastrin (G) and pepsinogen (PG). However, the changes in serum level of such peptides during or just after eradication therapy have not been well investigated. In this study, we evaluated the changes in serum G and PG levels at the end of eradication therapy, and then investigated the relation to the duodenal erosion following eradication. Methods: We randomly treated 318 patients (104 female and 318 men, mean age 51 years) with abdominal symptom (109 gastric ulcer (GU), 113 duodenal ulcer (DU), 32 gastro-duodenal ulcer (GDU), and 64 atrophic gastritis (AG». Before eradication, endoscopy was performed and patients with duodenal erosion were excluded. One month after eradication, endoscopy was performed to check duodenal erosion, and Hip culture, histology, and urea breath test performed to assess Hip treatment. We determined G and PG level in sera at three time points: before eradication, at the end of eradication, and one month after eradication. Results: In 272 (85.5%) cured patients, 39 (14.3%) patients had new duodenal erosions. In 46 (14.5%) patients with unsuccessful treatment, no duodenal erosion appeared. Duodenal erosion developed in 27.3%, 10.7%, 9.1%, and 0% in the patients with DU, GDU, GU, and AG. The prevalence of duodenal erosion after Hip eradication was significantly higher (p < 0.005) in DU patients than in GU, and AG patients. In cured patients, G, PG-I, II, and IIII level one month after eradication were significantly decreased compared to those measured before eradication (p < 0.005). At the end of eradication, G and PG-I level were significantly higher than before eradication (p < 0.0001). In uncured patients, no changes were seen. In the patients with new duodenal erosions, G, PG-I, II, and IIII levels were similar to non-duodenal erosion patients before eradication and one month after eradication. However, at the end of eradication, only PG-I levels were significantly higher (p < 0.0001) than in the patients with non-duodenal erosion. Conclusions: 1. Successful Hip treatment causes a temporary high G and PG-I response at the end of eradication therapy. 2. Increased PG-I might be a kind of gastric mucosal response to H.p eradication since this temporary high level of serum PG-I is strongly associated with development of new erosions in duodenum. 3. These phenomenon strongly bring about duodenal mucosal damage by excess acid secretion and PG-I following eradication therapy.