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Immune reactions against elongation factor 2 kinase: specific pathogenesis of gastric ulcer from Helicobacter pylori infection.

Ayada K, Yokota K, Kawahara Y, Yamamoto Y, Hirai K, Inaba T, Kita M, Okada H, Yamamoto K, Oguma K - Clin. Dev. Immunol. (2009)

Bottom Line: This antigen was over-expressed by a stressful (heat-stressed) environment, and was identified as elongation factor 2 kinase (EF-2K) by western blotting.The target cells (HGC-27) expressed EF-2K and MHC-class I together with costimulatory molecules from heat stress.This antigen specific immune mechanism could have a prominent role in the pathogenesis of GU.

View Article: PubMed Central - PubMed

Affiliation: Department of Bacteriology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan. k-ayada@sj8.so-net.ne.jp

ABSTRACT
Helicobacter pylori (H. pylori) infection is a definite causative factor for gastric ulcers (GUs). In the present study we detected a specific antigen of gastric epithelial cells (HGC-27) using cell ELISA, which was recognized by the sera of GU patients (n = 20) but not in patients with chronic gastritis (CG; n = 20) or in healthy volunteers (HC; n = 10). This antigen was over-expressed by a stressful (heat-stressed) environment, and was identified as elongation factor 2 kinase (EF-2K) by western blotting. The GU patients' lymphocytes stimulated by H. pylori specifically disrupted heat-stressed HGC-27 cells in a cytotoxic assay. In flow cytometry, the effector cells (lymphocytes) from GU patients were significantly differentiated to T helper type 1 lymphocyte (Th1) and cytotoxic T lymphocyte (CTL) as opposed to those from CG patients. The target cells (HGC-27) expressed EF-2K and MHC-class I together with costimulatory molecules from heat stress. This antigen specific immune mechanism could have a prominent role in the pathogenesis of GU.

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Specific cytotoxicity induced by lymphocytes from GU patients. 4 target cells were prepared. (a) HGC-27 cells treated with heat stress and patients' sera, (b) HGC-27 cells treated with heat stress, (c) HGC-27 cells treated with patients' sera, (d) nontreated HGC-27 cells. PBMCs were taken from GU patients (n = 8). PBMCs stimulated with conA and H. pylori (■) in addition to IL-12 (∆) or IL-4 (●) were used as effector cells. Nonstimulated PBMCs (◊) were also used as a control. Both cells reacted with various E/T ratios. An E/T ratio dependent cytotoxicity was observed only against heat-stressed HGC-27 cells or heat-stressed and sera-treated HGC-27 cells. The cytotoxicities of effector cells stimulated by H. pylori lysate were significantly enhanced, regardless of additional cytokine stimulations (*; P < .05). (e) The comparison of cytotoxicities among lymphocytes from CG, GU, and GU posteradication patients. Target cells were HGC-27 cells treated with heat stress and patients' sera. Effector cells were PBMCs stimulated with conA, H. pylori, and IL-12. The E/T ratio was 4. Specific cytotoxicity was only observed in GU patients' lymphocytes.
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fig3: Specific cytotoxicity induced by lymphocytes from GU patients. 4 target cells were prepared. (a) HGC-27 cells treated with heat stress and patients' sera, (b) HGC-27 cells treated with heat stress, (c) HGC-27 cells treated with patients' sera, (d) nontreated HGC-27 cells. PBMCs were taken from GU patients (n = 8). PBMCs stimulated with conA and H. pylori (■) in addition to IL-12 (∆) or IL-4 (●) were used as effector cells. Nonstimulated PBMCs (◊) were also used as a control. Both cells reacted with various E/T ratios. An E/T ratio dependent cytotoxicity was observed only against heat-stressed HGC-27 cells or heat-stressed and sera-treated HGC-27 cells. The cytotoxicities of effector cells stimulated by H. pylori lysate were significantly enhanced, regardless of additional cytokine stimulations (*; P < .05). (e) The comparison of cytotoxicities among lymphocytes from CG, GU, and GU posteradication patients. Target cells were HGC-27 cells treated with heat stress and patients' sera. Effector cells were PBMCs stimulated with conA, H. pylori, and IL-12. The E/T ratio was 4. Specific cytotoxicity was only observed in GU patients' lymphocytes.

Mentions: We evaluated whether lymphocytes from the GU patients possessed any cytotoxicity against gastric cells. Specific cytotoxicity of the lymphocytes, which was dependent on the E/T ratio, was observed only when the heat-stressed HGC-27 cells or heat-stressed and sera-treated HGC-27 cells were employed as target cells (Figures 3(a), 3(b), 3(c), and 3(d)). Further, the patients' sera did not affect the cytotoxicities. These results suggested that this cytotoxity could target the antigenic peptide of EF-2K which was overexpressed on HGC-27 cells by heat stress and that the antibody-dependent cell-mediated cytotoxicity (ADCC) did not occur. Effector cells stimulated by H. pylori lysate and additional cytokines had significantly higher cytotoxicities than the control effecter cells (Figures 3(a) and 3(b)).


Immune reactions against elongation factor 2 kinase: specific pathogenesis of gastric ulcer from Helicobacter pylori infection.

Ayada K, Yokota K, Kawahara Y, Yamamoto Y, Hirai K, Inaba T, Kita M, Okada H, Yamamoto K, Oguma K - Clin. Dev. Immunol. (2009)

Specific cytotoxicity induced by lymphocytes from GU patients. 4 target cells were prepared. (a) HGC-27 cells treated with heat stress and patients' sera, (b) HGC-27 cells treated with heat stress, (c) HGC-27 cells treated with patients' sera, (d) nontreated HGC-27 cells. PBMCs were taken from GU patients (n = 8). PBMCs stimulated with conA and H. pylori (■) in addition to IL-12 (∆) or IL-4 (●) were used as effector cells. Nonstimulated PBMCs (◊) were also used as a control. Both cells reacted with various E/T ratios. An E/T ratio dependent cytotoxicity was observed only against heat-stressed HGC-27 cells or heat-stressed and sera-treated HGC-27 cells. The cytotoxicities of effector cells stimulated by H. pylori lysate were significantly enhanced, regardless of additional cytokine stimulations (*; P < .05). (e) The comparison of cytotoxicities among lymphocytes from CG, GU, and GU posteradication patients. Target cells were HGC-27 cells treated with heat stress and patients' sera. Effector cells were PBMCs stimulated with conA, H. pylori, and IL-12. The E/T ratio was 4. Specific cytotoxicity was only observed in GU patients' lymphocytes.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2712636&req=5

fig3: Specific cytotoxicity induced by lymphocytes from GU patients. 4 target cells were prepared. (a) HGC-27 cells treated with heat stress and patients' sera, (b) HGC-27 cells treated with heat stress, (c) HGC-27 cells treated with patients' sera, (d) nontreated HGC-27 cells. PBMCs were taken from GU patients (n = 8). PBMCs stimulated with conA and H. pylori (■) in addition to IL-12 (∆) or IL-4 (●) were used as effector cells. Nonstimulated PBMCs (◊) were also used as a control. Both cells reacted with various E/T ratios. An E/T ratio dependent cytotoxicity was observed only against heat-stressed HGC-27 cells or heat-stressed and sera-treated HGC-27 cells. The cytotoxicities of effector cells stimulated by H. pylori lysate were significantly enhanced, regardless of additional cytokine stimulations (*; P < .05). (e) The comparison of cytotoxicities among lymphocytes from CG, GU, and GU posteradication patients. Target cells were HGC-27 cells treated with heat stress and patients' sera. Effector cells were PBMCs stimulated with conA, H. pylori, and IL-12. The E/T ratio was 4. Specific cytotoxicity was only observed in GU patients' lymphocytes.
Mentions: We evaluated whether lymphocytes from the GU patients possessed any cytotoxicity against gastric cells. Specific cytotoxicity of the lymphocytes, which was dependent on the E/T ratio, was observed only when the heat-stressed HGC-27 cells or heat-stressed and sera-treated HGC-27 cells were employed as target cells (Figures 3(a), 3(b), 3(c), and 3(d)). Further, the patients' sera did not affect the cytotoxicities. These results suggested that this cytotoxity could target the antigenic peptide of EF-2K which was overexpressed on HGC-27 cells by heat stress and that the antibody-dependent cell-mediated cytotoxicity (ADCC) did not occur. Effector cells stimulated by H. pylori lysate and additional cytokines had significantly higher cytotoxicities than the control effecter cells (Figures 3(a) and 3(b)).

Bottom Line: This antigen was over-expressed by a stressful (heat-stressed) environment, and was identified as elongation factor 2 kinase (EF-2K) by western blotting.The target cells (HGC-27) expressed EF-2K and MHC-class I together with costimulatory molecules from heat stress.This antigen specific immune mechanism could have a prominent role in the pathogenesis of GU.

View Article: PubMed Central - PubMed

Affiliation: Department of Bacteriology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan. k-ayada@sj8.so-net.ne.jp

ABSTRACT
Helicobacter pylori (H. pylori) infection is a definite causative factor for gastric ulcers (GUs). In the present study we detected a specific antigen of gastric epithelial cells (HGC-27) using cell ELISA, which was recognized by the sera of GU patients (n = 20) but not in patients with chronic gastritis (CG; n = 20) or in healthy volunteers (HC; n = 10). This antigen was over-expressed by a stressful (heat-stressed) environment, and was identified as elongation factor 2 kinase (EF-2K) by western blotting. The GU patients' lymphocytes stimulated by H. pylori specifically disrupted heat-stressed HGC-27 cells in a cytotoxic assay. In flow cytometry, the effector cells (lymphocytes) from GU patients were significantly differentiated to T helper type 1 lymphocyte (Th1) and cytotoxic T lymphocyte (CTL) as opposed to those from CG patients. The target cells (HGC-27) expressed EF-2K and MHC-class I together with costimulatory molecules from heat stress. This antigen specific immune mechanism could have a prominent role in the pathogenesis of GU.

Show MeSH
Related in: MedlinePlus