title: New immunological investigations on Helicobacter pylori-induced gastric ulcer in patients.
abstract: Although Helicobacter pylori (Hp) plays an important role in the pathogenesis of chronic gastritis and gastric ulcer, little is known about the probable mechanisms of these types of gastrointestinal damage. To determine the precise mechanisms involved in ulcer formation, immune responses in patients with gastric ulcer (GUP) caused by Hp infection (Hp(+)) were compared with those of other gastritis patients (GP). The sensitivity and proliferation of peripheral blood mononuclear cells (PBMNCs) obtained from patients were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay against exposure with complex Hp crude antigen (HPCA) and mitogen (phytohemagglutinin, PHA). Production of inflammatory cytokines, including interleukin (IL)-1β and IL-8, in serum and supernatants of PBMNCs were then measured by ELISA. It was found that, after stimulation with PHA, both IL-8 and IL-1β concentrations in sera and supernatants as well as proliferation and sensitivity were statistically greater in GUP Hp(+) than GP Hp(-) . Furthermore, HPCA inhibited the proliferation of PBMNCs dose-dependently; however, it stimulated IL-8 and IL-1β production in supernatants of mononuclear cells. Therefore, the up-regulated concentrations of IL-8 and IL-1β may have been caused by increase in the size of mononuclear cell subpopulations or in their cytokine secretory activity, indicating the greatest cell responsiveness in GUP Hp(+) patients. These results suggest that tissue damage and ulcers occur in patients who produce more IL-8 and IL-1β than patients who do not develop ulcers; the former consequently have more activated immune cells at the site of infection. Therefore, both host responses and Hp virulence factors may be involved in the development of gastric ulcers.
authors.affiliation: Department of Immunology, Professor Alborzi Clinical Microbiology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Hamid Reza
authors.initials: HR
authors.lastname: Rahimi
authors.forename: Manoochehr
authors.initials: M
authors.lastname: Rasouli
authors.forename: Akram
authors.initials: A
authors.lastname: Jamshidzadeh
authors.forename: Shohreh
authors.initials: S
authors.lastname: Farshad
authors.forename: Mehdi Saberi
authors.initials: MS
authors.lastname: Firoozi
authors.forename: Ali Reza
authors.initials: AR
authors.lastname: Taghavi
authors.forename: Simin
authors.initials: S
authors.lastname: Kiany
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D049109:Cell Proliferation; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D016481:Helicobacter Infections / Q000150:complications / Q000276:immunology* / Q000382:microbiology; D016480:Helicobacter pylori / Q000276:immunology / Q000472:pathogenicity*; D006801:Humans; D053583:Interleukin-1beta / Q000097:blood / Q000276:immunology* / Q000378:metabolism; D016209:Interleukin-8 / Q000097:blood / Q000276:immunology* / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008297:Male; D008875:Middle Aged; D013194:Staining and Labeling; D013276:Stomach Ulcer / Q000276:immunology* / Q000473:pathology*; D013778:Tetrazolium Salts / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism; D055815:Young Adult
chemical_list: D053583:Interleukin-1beta; D016209:Interleukin-8; D013778:Tetrazolium Salts; D013844:Thiazoles; C022616:thiazolyl blue