Detection of Helicobacter pylori associated antigen and heat shock protein 60 on follicular dendritic cells in the germinal centres of low grade B cell lymphoma of gastric mucosa associated lymphoid tissue (MALT)

Crude Preparations of Helicobacter pylori Outer Membrane Vesicles Induce Upregulation of Heme Oxygenase-1 via Activating Akt-Nrf2 and mTOR-IκB Kinase-NF-κB Pathways in Dendritic Cells

Helicobacter pylori sheds outer membrane vesicles (OMVs) that contain many surface elements of bacteria. Dendritic cells (DCs) play a major role in directing the nature of adaptive immune responses against H. pylori, and heme oxygenase-1 (HO-1) has been implicated in regulating function of DCs. In addition, HO-1 is important for adaptive immunity and the stress response. Although H. pylori-derived OMVs may contribute to the pathogenesis of H. pylori infection, responses of DCs to OMVs have not been elucidated. In the present study, we investigated the role of H. pylori-derived crude OMVs in modulating the expression of HO-1 in DCs. Exposure of DCs to crude H. pylori OMVs upregulated HO-1 expression. Crude OMVs obtained from a cagA-negative isogenic mutant strain induced less HO-1 expression than OMVs obtained from a wild-type strain. Crude H. pylori OMVs activated signals of transcription factors such as NF-κB, AP-1, and Nrf2. Suppression of NF-κB or Nrf2 resulted in significant attenuation of crude OMV-induced HO-1 expression. Crude OMVs increased the phosphorylation of Akt and downstream target molecules of mammalian target of rapamycin (mTOR), such as S6 kinase 1 (S6K1). Suppression of Akt resulted in inhibition of crude OMV-induced Nrf2-dependent HO-1 expression. Furthermore, suppression of mTOR was associated with inhibition of IκB kinase (IKK), NF-κB, and HO-1 expression in crude OMV-exposed DCs. These results suggest that H. pylori-derived OMVs regulate HO-1 expression through two different pathways in DCs, Akt-Nrf2 and mTOR–IKK–NF-κB signaling. Following this induction, increased HO-1 expression in DCs may modulate inflammatory responses in H. pylori infection.

Helicobacter pylori-an infectious risk factor for atherosclerosis?

Accumulating evidence implicates Helicobacter pylori (H. pylori) infection in the pathogenesis of certain diseases localized outside the stomach, particularly those characterized by persistent and low-grade systematic inflammation. Recently, the role of H. pylori infection in the development of atherosclerosis and its clinical complications has received attention. Atherosclerosis is a high-cost disease, and acute events resulting from this condition rank first among morbidity and mortality statistics in most industrialized countries. Atherosclerosis is a multifactorial disorder, and traditional risk factors explain only 50% of its etiology. Therefore, identifying new risk factors for atherosclerosis is necessary. Serological studies indicate that chronic H. pylori infection, especially that with more virulent strains, may predispose patients to the onset of atherosclerosis and related adverse clinical events, and PCR studies have detected H. pylori DNA in atherosclerotic plaques, although this finding remains controversial. If this association were to be confirmed, its importance to public health would be substantial, as the eradication of H. pylori is more straightforward and less costly than the long-term treatment of other risk factors. This review investigates the potential relationship between H. pylori infection and atherosclerosis from both epidemiological and pathogenic perspectives and characterizes the potential mechanisms underlying this correlation.

Hsp60 chaperonopathies and chaperonotherapy: targets and agents

INTRODUCTION

Hsp60 (Cpn60) assembles into a tetradecamer that interacts with the co-chaperonin Hsp10 (Cpn10) to assist client polypeptides to fold, but it also has other roles, including participation in pathogenic mechanisms.

AREA COVERED

Hsp60 chaperonopathies are pathological conditions, inherited or acquired, in which the chaperone plays a determinant etiologic-pathogenic role. These diseases justify selection of Hsp60 as a target for developing agents that interfere with its pathogenic effects. We provide information on how to proceed.

EXPERT OPINION

The information available encourages the development of ways to improve Hsp60 activity (positive chaperonotherapy) when deficient or to block it (negative chaperonotherapy) when pathogenic. Many questions are still unanswered and obstacles are obvious. More information is needed to establish when and why autologous Hsp60 becomes a pathogenic autoantigen, or induces cytokine formation and inflammation, or favors carcinogenesis. Clarification of these points will take considerable time. However, analysis of the Hsp60 molecule and a search for active compounds aimed at structural sites that will affect its functioning should continue without interruption. No doubt that some of these compounds will offer therapeutic hopes and will also be instrumental for dissecting structure-function relationships at the biochemical and biological (using animal models and cultured cells) levels.

Dendritic cell function in the host response to Helicobacter pylori infection of the gastric mucosa

Dendritic cells (DCs) play an important role as antigen-presenting cells that direct the nature of the adaptive immune response. Subtypes are differentiated by lineage, tissue, marker expression and function. Their function in promoting regulatory T cells in the gut to maintain immunologic homeostasis is well documented, but their role in the Helicobacter pylori-infected stomach is less clear. Some analyses of bone marrow-derived DCs stimulated with H. pylori have demonstrated proinflammatory potential based on secretion of IL-12 or IL-23 or activation of Th1 and Th17 cells. Other analyses indicate that H. pylori-activated DCs are less responsive compared with other gastrointestinal bacteria and activate DCs to promote Treg development. DC depletion in mice supports a role for DCs in down-regulating H. pylori-induced gastritis. These data indicate that gastric DCs recognize H. pylori much like DCs in the gut that recognize commensal organisms and promote a regulatory T-cell response. This is consistent with a growing body of literature documenting the prevalence and function of Treg cells in the host response to H. pylori. Research is now focused on characterizing how H. pylori induces such activity in DCs and identifying the mechanisms by which H. pylori-activated DCs activate Treg cells.

Autoimmunity, infectious immunity, and atherosclerosis

INTRODUCTION

Vascular inflammation is common in certain systemic autoimmune diseases and contributes to the oxidation of low-density lipoprotein (oxLDL) and oxLDL/beta2-glycoprotein I (beta2GPI) complex formation. These complexes have been implicated as proatherogenic autoantigens that participate in the development of atherosclerotic disease.

DISCUSSION

We have demonstrated that the in vitro macrophage uptake of oxLDL/beta2GPI complexes increases in the presence of IgG anti-beta2GPI antibodies and that IgG immune complexes containing oxLDL/beta2GPI upregulate the expression of both scavenger and Fcgamma receptors to activate beta2GPI specific T cells. Some persistent infections may cause immune responses that promote atherogenesis. Cellular immunity (Th1) against Helicobacter pylori (H. pylori) derived heat shock protein 60 (Hp-HSP60) cross-reacts with endogenous HSP60 to cause cardiovascular disease likely by molecular mimicry.

CONCLUSION

Infectious cellular response may be proatherogenic,while the humoral response (antibody production) maybe protective. We review the recent progress in our understanding of autoimmunity and infectious immunity that promote atherosclerosis.

Regulation of cellular immunity prevents Helicobacter pylori-induced atherosclerosis

Helicobacter pylori (H. pylori) is a predominant pathogen that causes not only gastroduodenal diseases but also extra-alimentary tract diseases. In this study, we demonstrated that H. pylori infection promoted atherogenesis in heterozygous apoe(+/ --) ldlr(+/--) mice. The male mice were fed with high fat diet from the age of 6 weeks. At the age of 16 weeks, development of atherosclerotic lesions was observed in the H. pylori-infected mice, and it seemed to be associated with an elevation of Th1-immune response against H. pylori origin-heat shock protein 60 (Hp-HSP60) and an increment of transendothelial migration of T cells. Subcutaneous immunisation with Hp-HSP60 or H. pylori eradication with antibiotics significantly reduced the progression of atherosclerosis, accompanied by a decline of Th1 differentiation and reduction of their chemotaxis beyond the endothelium. Thus, oral infection with H. pylori accelerates atherosclerosis in mice and the active immunisation with Hp-HSP60 or the eradication of H. pylori with antibiotics can moderate/prevent cellular immunity, resulting in a reduction of atherosclerosis.

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

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.

Ectopic lymphoid tissues and local immunity

Ectopic or tertiary lymphoid tissues develop at sites of inflammation or infection in peripheral, non-lymphoid organs. These tissues are architecturally similar to conventional secondary lymphoid organs, with separated B and T cell areas, specialized populations of dendritic cells, well-differentiated stromal cells and high endothelial venules. Ectopic lymphoid tissues are often associated with the local pathology that results from chronic infection or chronic inflammation. However, there are also examples in which ectopic lymphoid tissues appear to contribute to local protective immune responses. Here we review how ectopic lymphoid structures develop and function in the context of local immunity and pathology.

Antibodies against heat shock protein 60 derived from Helicobacter pylori: diagnostic implications in cardiovascular disease

Immune responses against heat shock protein 60 (HSP60) of pathogen-origin are thought to be defensive events which, due to molecular mimicry, misdirect to a human counterpart. Therefore, atherosclerosis may be serologically predicted by anti-HSP60 antibodies (Abs). In the present study, we analyzed the clinical prevalence of the serum IgG Abs against Helicobacter pylori (Hp)-derived HSP60 (Hp-HSP60) or its peptide fragments in patients with cardiovascular disease (CVD; n=250), as compared to those in age- and gender-matched non-CVD patients (n=293). Anti-Hp cell lysate Abs frequently appeared in Hp-infected patients who were not associated with CVD. In contrast, Abs against the particular amino acid sequence Hp-HSP60(II3) (II3 region, Glu(141)-Leu(160), in Hp-HSP60) predominantly appeared in CVD patients, as well as IgG anti-human HSP60 (Hu-HSP60(w)). Furthermore, neither titer of anti-Hp-HSP60(II3) nor anti-Hu-HSP60(w) Abs was correlated with the levels of high sensitivity C-reactive protein (hsCRP). This data strongly suggested that IgG anti-Hp-HSP60(II3) Abs cross-reacted with Hu-HSP60(w) were independent diagnostic markers relevant to CVD. Further, the 20 amino acid residues (Glu(141)-Leu(160)) might be predominant CVD-associated epitopes that induce anti-Hu-HSP60 auto-Abs, whose location was predicted in the tertiary structure of Hu-HSP60.

Mitochondrial alterations in human gastric carcinoma cell line

We compared mitochondrial function, morphology, and proteome in the rat normal gastric cell line RGM-1 and the human gastric cancer cell line AGS. Total numbers and cross-sectional sizes of mitochondria were smaller in AGS cells. Mitochondria in AGS cells were deformed and consumed less oxygen. Confocal microscopy indicated that the mitochondrial inner membrane potential was hyperpolarized and the mitochondrial Ca(2+) concentration was elevated in AGS cells. Interestingly, two-dimensional electrophoresis proteomics on the mitochondria-enriched fraction revealed high expression of four mitochondrial proteins in AGS cells: ubiquinol-cytochrome c reductase, mitochondrial short-chain enoyl-coenzyme A hydratase-1, heat shock protein 60, and mitochondria elongation factor Tu. The results provide clues as to the mechanism of the mitochondrial changes in cancer at the protein level and may serve as potential cancer biomarkers in mitochondria.

Infectious agents in mucosa-associated lymphoid tissue-type lymphomas: pathogenic role and therapeutic perspectives

Mucosa-associated lymphoid tissue (MALT) lymphoma probably constitutes the best in vivo model showing how complex interplay between B lymphocytes and the surrounding microenvironment may lead to a neoplastic disorder. After the seminal discovery of the pathogenic association between Helicobacter pylori and gastric MALT lymphomas, evidence suggests the possible involvement of other infectious agents in the development of MALT lymphomas arising at different body sites. Although several other bacteria (Borrelia burgdorferi, Campylobacter jejuni, and Chlamydia psittaci) and viruses (Hepatitis C virus) seem to play a role in lymphomas presenting at different locations, a possible common pathogenic mechanism is emerging. Several lines of evidence suggest that different infectious agents might provide a chronic antigenic stimulation that elicits host immune responses able to promote clonal B-cell expansion. This model is also substantiated by the increasing number of patients with MALT lymphomas who exhibit objective clinical responses after antimicrobial therapy. A multidisciplinary approach is critical to better understand the complex etiopathogenesis of MALT lymphomas with the final goal to dissect the clinicopathologic heterogeneity of these disorders and design more tailored preventive and therapeutic approaches.

Innate immune recognition of the extracellular mucosal pathogen, Helicobacter pylori

Toll-like receptor (TLR) molecules play a frontline role in the defence of the host against infection by microbial pathogens. These molecules, together with the recently described Nod family proteins, have been shown to trigger innate immune responses in host cells via the recognition of highly conserved microbial structures. TLR4, which is the best-characterised of these "pathogen-recognition molecules" (PRMs), was the first to be shown to recognise a specific microbial component: the lipopolysaccharide (LPS) from Gram-negative bacteria. The molecular specificities of the remaining PRMs have, in nearly all cases, now also been elucidated. Host cells belonging to the myeloid cell lineage are known to be particularly responsive to these microbial constituents. Conversely, other cell types such as epithelial cells, were generally thought to be hypo-responsive to stimulation by such molecules. New evidence suggests that these cells are in fact likely to play a fundamental role in host defence against pathogenic micro-organisms. Indeed, epithelial cells afford an initial barrier against the host microflora, and appear to be able to differentiate between pathogenic and commensal micro-organisms. This review article will discuss current knowledge regarding innate immune responses in epithelial and myeloid cells to the model non-invasive pathogen, Helicobacter pylori, which is a major cause of upper gastrointestinal tract disease in humans.

Serum antibodies to Helicobacter pylori and its heat-shock protein 60 correlate with the response of gastric mucosa-associated lymphoid tissue lymphoma to eradication of H. pylori

BACKGROUND AND AIMS

Eradication of Helicobacter pylori leads to regression of mucosa-associated lymphoid tissue (MALT) lymphomas. In this study, we measured serum antibodies to H. pylori and H. pylori-recombinant heat-shock protein 60 (rHSP60) in patients with gastric MALT lymphoma to determine whether humoral immune responses to the bacterial antigens correlate with the efficacy of eradication therapy.

METHODS

Serum samples were obtained from 33 patients with H. pylori-positive gastric MALT lymphoma before undergoing therapy to eradicate the bacteria. Anti-H. pylori antibodies were measured in a commercial assay and in immunoassays to lysates and rHSP60 which were prepared from ATCC 43504 strain.

RESULTS

Helicobacter pylori were eradicated in all 33 patients, and the lymphoma completely regressed histologically in 26 patients (79%). Pre-treatment titers of serum antibody to H. pylori and to rHSP60 in the patients whose tumor regressed were significantly higher than titers in patients whose tumors did not regress (p =.0011 and.035, respectively). By logistic regression analysis, age (odds ratio = 0.88, 95% confidence interval = 0.80-0.99), endoscopic appearance (0.053, 0.004-0.65), titers of anti-H. pylori antibodies (67.6, 2.5-1800), and titers of anti-rHSP60 antibody (6.4, 1.2-36) were identified as significantly associated factors with the outcome of MALT lymphoma.

CONCLUSIONS

Measurement of serum antibodies to H. pylori and HSP60 might be useful for predicting the response of gastric MALT lymphoma to eradication of H. pylori.

Immune response in Helicobacter pylori-induced low-grade gastric-mucosa-associated lymphoid tissue (MALT) lymphoma

We have reported previously that heat-shock protein 60 kDa (hsp60) of Helicobacter pylori is an important antigen in the pathogenesis of gastric mucosa-associated lymphoid tissue (MALT) lymphoma. In order to investigate associations with host immune reactions and hsp60 antigen, CD40 ligand (CD40L) expression and cytokine production were analysed following stimulation with hsp60. To provide a clear antigen-driven immune response, peripheral blood mononuclear cells (PBMC) from patients with low-grade MALT lymphoma and gastritis and those from healthy volunteers were stimulated with recombinant H. pylori hsp60 and H. pylori cell lysate in the presence of cytokines (IL4 and granulocyte-macrophage colony-stimulating factor). mRNA expression was also analysed by a cDNA microarray containing 1100 genes. Expression of CD40L on PBMCs of patients with MALT lymphoma was increased by cytokines or by combination with stimulation with hsp60 antigens. The production of IL4 in PBMC cultures was increased in patients with MALT lymphoma; however, production of IFN-gamma was at low levels. DNA microarray analysis indicated increased levels of HLA-DR and integrin mRNAs. In cases of low-grade MALT lymphoma, adaptive immune responses against hsp60 may be enhanced by host factors, such as antigen presentation and T-cell activation, resulting in B-cell proliferation, which can be demonstrated during chronic H. pylori infection.

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Tumor-infiltrating T cells with similar antigen binding sites in different mucosa-associated lymphoid tissue type B cell lymphomas

B cell lymphomas of mucosa-associated lymphoid tissue (MALT)-type arise on the background of chronic inflammation due to either autoimmunity or infection at various sites of the organism. Characteristically the tumor-infiltrating T cells found in large numbers in MALT-type lymphomas are predominantly of CD4(+) phenotype and may have impact on tumor pathogenesis. To assess whether the chromosomal translocation t(11;18)(q21; q21) that is specific for at least a subset of MALT-type lymphomas may have an impact on tumor environment, we investigated the antigen binding sites of tumor-infiltrating T cells from one t(11;18)-positive tumor of the thyroid and one t(11;18)-negative tumor of the stomach. MHC Allelotyping was performed and revealed common alleles in HLA-DR and HLA-DQ loci. Cloning and sequencing of the complementary determining region 3 in V(beta2) chains of T cell receptors demonstrated the use of identical J(beta)segments in both patients, suggestive for recognition of the same antigen. We therefore suggest that tumor-infiltrating CD4(+) T cells are tightly integrated in MALT-type lymphoma immunoarchitecture irrespective of genetic background and localization of the tumors.

B-cell lymphomas involving the skin associated with hepatitis C virus infection

BACKGROUND

A role for hepatitis C virus (HCV) infection has been suggested in the pathogenesis of non-Hodgkin lymphomas (NHL).

AIM

To evaluate the characteristics of cutaneous lymphomas occurring in HCV-infected patients, and to investigate the hypothesis of a direct infection of malignant cells.

METHODS

Three patients showing a positive serology for HCV and a cutaneous lymphoma were studied. Analysis of HCV replication was performed using reverse transcriptase-polymerase chain reaction. The presence of HCV RNA was also assessed in biopsies from lesional skin and in a lymph node in one case. Genotype characterization was carried out on the basis of LiPA genotyping assays using viral genomic amplification products.

RESULTS

Cutaneous NHL occurred in patients with chronic and replicative HCV infection, and exhibited a B-cell phenotype (one diffuse large B-cell lymphoma, one follicular lymphoma, and one marginal zone B-cell lymphoma). All patients were male; two of them were former intravenous drug abusers, while the HCV contamination route was unknown in the third. The search for HCV RNA in the skin and in lymph nodes yielded negative results. HCV genotypes were 1b in two cases and 3a in one case.

CONCLUSION

These results show that a subset of B-cell cutaneous NHL is associated with a replicative HCV infection and suggest that HCV is not involved in lymphomagenesis through a direct infection of malignant cells. The ability of HCV to trigger a chronic B-cell lymphoproliferation could represent another mechanism, while a fortuitous association cannot be excluded.

Immunoglobulin G1 antibody response to Helicobacter pylori heat shock protein 60 is closely associated with low-grade gastric mucosa-associated lymphoid tissue lymphoma

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is related to Helicobacter pylori infection. Specifically, it has been pointed out that pathogenesis of MALT lymphoma involves the 60-kDa heat shock protein (hsp60). To investigate humoral immune responses to the H. pylori hsp60 in patients with gastroduodenal diseases and patients with MALT lymphoma, the hsp60 of H. pylori was expressed with a glutathione S-transferase fusion protein and was purified (recombinant hsp60). Sera were obtained from H. pylori-positive patients with gastroduodenal diseases (MALT lymphoma, n = 13; gastric ulcer, n = 20; duodenal ulcer, n = 20; gastritis, n = 20) and from H. pylori-negative healthy volunteers (n = 9). Sera from patients with MALT lymphoma were also obtained at two times: before and after eradication therapy. Antibodies to hsp60 and H. pylori were assessed by enzyme-linked immunosorbent assay. The levels of immunoglobulin G (IgG) antibodies to the hsp60 of H. pylori-positive patients with gastroduodenal diseases were significantly elevated compared to those in the controls. The levels of IgG1 antibodies to hsp60 were elevated and correlated with the levels of anti-H. pylori antibodies in patients with MALT lymphoma. Humarol immunity against hsp60 may be important and relevant to gastroduodenal diseases induced by H. pylori infection.

Superantigens and autoantigens may be involved in the pathogenesis of gastric mucosa-associated lymphoid tissue lymphoma

To clarify the origin of tumor cells and the possible role of antigens in the pathogenesis of mucosa-associated lymphoid tissue lymphoma (MALTL) of the stomach, we analyzed the DNA sequences of the immunoglobulin (Ig) variable region gene from tumor cells of 4 patients with low-grade and 2 patients with high-grade MALTL associated with Helicobacter pylori infection. There were few somatic mutations in the Ig variable region gene, but intraclonal variations were observed in 2 of the 4 low-grade MALTL cases. In the remaining 2 low-grade MALTL and 1 of the 2 high-grade MALTL cases, somatic mutations and intraclonal variations were evident. In contrast, somatic mutations in the Ig variable region gene were prominent, but intraclonal variation was absent in the other high-grade MALTL cases. The deduced amino acid sequences of the antigen-binding fragments (Fab) from 2 MALTL cases revealed homology with anti-thyroglobulin antibodies, 3 MALTL cases with lupus anti-DNA antibodies, and 1 MALTL case with a rheumatoid factor. Furthermore, the heavy-chain variable region 3 (V(H)3) family genes were used in 5 of the 6 MALTL cases and had conserved amino acid residues for binding to staphylococcal protein A (SpA), a superantigen of B cells. Considering that another superantigen, protein Fv, competes for binding to Fab with SpA and has been shown to play a major role in immune defenses against gut pathogens, SpA and possibly protein Fv may contribute to the development of MALTL. Thus, these observations suggest that most gastric MALTLs arise from memory B cells that are preliminarily activated by superantigens and autoantigens.

Effect of jianpiyiqi prescription on the expression of heat shock proteins in acetic acid-induced chronic gastric ulcer rats

To investigate the effect of Jianpiyiqi prescription on the expression of heat shock proteins (HSPs) and the changes of HSPs in gastric-ulcerated rats, the rat model of chronic gastric ulcer was induced by acetic acid. The SABC immunohistochemical method was used to observe HSP70 of mucosa around the gastric ulcer. Imaging analysis was performed. Western dot blot was used to detect HSPs contents in the plasma and gastric mucosal homogenate in each group. The results showed that HSP70 contents of the mucosa around the gastric ulcer in the model group and ranitidine-treated group were increased as compared with control group (P < 0.01). Jianpiyiqi could increase the expression of HSP70 of the mucosa around the gastric ulcer further as compared with that in the model group and ranitidine-treated group (P < 0.01). The HSP70 contents in the serum and mucosa in the model group and ranitidine-treated group were increased as compared with control group (P < 0.01, P < 0.05 respectively). HSP70 of serum and mucosa in the Jianpiyiqi-treated group was higher than in the model group and ranitidine-treated group (P < 0.05, P < 0.01 respectively). It was concluded that HSP might play a role in the process of pathophysiology of gastric ulcer. Jianpiyiqi could enhance gastric ulcer-healing through the protective mechanism of HSPs.

Antibody to heat shock protein can be used for early serological monitoring of Helicobacter pylori eradication treatment

Infection with Helicobacter pylori induces humoral immune responses against various antigens of the bacterium. Heat shock proteins (hsps) are immunodominant antigens in various diseases including H. pylori infection. In the present study, we measured the anti-hsp antibody titers in 42 patients with H. pylori-infected peptic ulcers during a bacterial eradication study. The patients were treated with a proton pump inhibitor and antimicrobial agents to eradicate the organism. Their sera were obtained at pretreatment and at 1 month and 6 months after the eradication therapy. The titers of immunoglobulin G antibodies to the H. pylori hsp, whole-cell lysate, and urease (30-kDa subunit) antigens in serum were measured by a capture enzyme-linked immunosorbent assay. The levels of H. pylori hsp60 antibodies in sera collected 1 month after treatment had declined significantly, even when changes in the titers of antibodies to whole-cell and urease antigens were not apparent. These results suggest that measurement of antibodies to H. pylori hsp60 in serum is useful for the early monitoring of the effectiveness of eradication therapy.

Gastric ulcers in SCID mice induced by Helicobacter pylori infection after transplanting lymphocytes from patients with gastric lymphoma

BACKGROUND & AIMS

Several studies have indicated that host factors are important in Helicobacter pylori-induced gastroduodenal diseases. We examined the pathological role of host immune responses in H. pylori infection by reconstituting components of the human immune system into severe combined immunodeficient (SCID) mice by transplantation of peripheral blood mononuclear cells (PBMCs) from H. pylori-infected patients.

METHODS

PBMCs obtained from patients with mucosa-associated lymphoid tissue (MALT) lymphoma were injected intraperitoneally into SCID mice, designated MALToma-hu-SCID mice. One month after transplantation, H. pylori was administered orally to the mice. The mice were killed and examined for pathological changes and immunologic features.

RESULTS

Human lymphocytes were detected in hu-SCID mice, and T- and B-cell functions were preserved for 1 month. Administration of H. pylori led to gastric ulcers with bleeding in the MALToma-hu-SCID mice. The gastric mucosa of control mice injected with Escherichia coli or transplanted with PBMCs from patients with peptic ulcers or gastritis or from healthy volunteers showed no pathological changes.

CONCLUSIONS

Host immune responses against H. pylori appear to be involved in the development of gastric ulcers in patients who have MALT lymphoma.

Antibodies to human gastric epithelial cells and heat shock protein 60 in Helicobacter pylori positive mucosa associated lymphoid tissue lymphoma

BACKGROUND

Development of gastric mucosa associated lymphoid tissue (MALT) lymphoma is thought to be closely associated with host immune reactions to Helicobacter pylori.

AIM

To investigate humoral immune responses in patients with MALT lymphoma to antigens shared by H pylori and human gastric epithelial cells.

METHODS

Sera were obtained from H pylori positive patients with MALT lymphoma (n = 11) or other gastroduodenal diseases (peptic ulcer, n = 40; non-ulcer dyspepsia, n = 20) and from H pylori negative healthy control subjects (n = 10). Antibodies to HGC-27 human gastric epithelial cells and human recombinant heat shock protein (Hsp) 60 were examined using an enzyme linked immunosorbent assay (ELISA) and immunoblotting.

RESULTS

Antibody titres to HGC-27 cells were significantly elevated in H pylori positive patients with MALT lymphoma when compared with titres in patients with other gastroduodenal diseases and in healthy subjects. Immunoblotting of sera from patients with MALT lymphoma often detected a band with a molecular mass corresponding to Hsp60, and both ELISA and immunoblotting showed elevated antibody titres to the recombinant human Hsp60. Antigenic similarity between Hsp60 and H pylori HspB was documented by immunoblotting experiments.

CONCLUSIONS

Autoantibodies reactive with host gastric epithelial cells are often increased in MALT lymphoma, and Hsp60 is a major target antigen. Immune responses induced by immunological cross reactivity between H pylori HspB and human Hsp60 in gastric epithelium may be involved in the development of MALT lymphoma.