Lactobacillus gasseri K7 modulates the blood cell transcriptome of conventional mice infected with Escherichia coli O157:H7.

AIMS: As the immune cells underlying the intestinal barrier sense luminal microbial signals, blood cell transcriptomics may identify subclinical changes triggered by gut bacteria that may otherwise not be detected. We have therefore investigated how Lactobacillus gasseri K7 and enterohemorrhagic Escherichia coli O157:H7 modulate the blood cell transcriptome of mice possessing an intact microbiota. METHODS AND RESULTS: We have analysed the transcriptome of five groups of C57BL/6J mice: (i) control, (ii) inoculated with a single dose of E. coli, (iii) inoculated during 2 weeks with Lact. gasseri, (iv) co-inoculated with E. coli and Lact. gasseri, (v) inoculated with Lact. gasseri prior to E. coli infection. The transcriptome could distinguish between the five treatment groups. Gene characteristics of bacterial infection, in particular inflammation, were upregulated in the mice inoculated with E. coli. Lact. gasseri had only mild effects on the transcriptome but modified the gene expression induced by E. coli. CONCLUSIONS: The transcriptome differentiates mice inoculated orally with E. coli, Lact. gasseri and combinations of these two strains. SIGNIFICANCE AND IMPACT OF THE STUDY: These results suggest that the blood cell transcriptome can be used as a source of biomarkers to monitor the impact of probiotics in subclinical models of infectious disease.

Cytotoxic T-Cells in Peripheral Blood in Women with Endometriosis.

Aim: The etiology of endometriosis remains unknown, but increasing evidence suggests that immune regulation may be important. Our study aimed to evaluate peripheral blood lymphocyte subpopulations during the menstrual cycle in women with peritoneal and ovarian endometriosis relative to healthy women. Methods: In this study, 65 women with endometriosis (37 in the follicular phase and 28 in the luteal phase of the menstrual cycle) and 61 healthy women (33 in the follicular phase and 28 in the luteal phase) were enrolled. Flow cytometric analysis measured peripheral blood lymphocyte subpopulations. The serum levels of cortisol were also determined. Results: In healthy controls, we detected an increased concentration of cytotoxic (CD8+) T cells and activated (HLA-DR) T cells in the luteal phase compared with the follicular phase of the menstrual cycle (p = 0.020 and p = 0.045), whereas no such fluctuation was detected in endometriosis. However, a marked increase in regulatory T-cell concentration in the luteal phase was detected only in endometriosis patients (p = 0.005). Women with endometriosis had higher levels of serum cortisol (p = 0.022), which correlated with the concentration of regulatory T cells (p = 0.048). Conclusions: Women with endometriosis do not exhibit fluctuations in the concentrations of cytotoxic and activated peripheral blood lymphocytes during the menstrual cycle. The marked fluctuation of regulatory T cells detected in endometriosis could be attributed to altered immune response.

In vitro and in vivo reactivity to fungal cell wall agents in sarcoidosis.

Sarcoidosis is an inflammatory disease. Epidemiological and treatment studies suggest that fungi play a part in the pathogenesis. The aim of this work was to study the effect of fungal cell wall agents (FCWA) on the in vitro secretion of cytokines from peripheral blood monocytes from subjects with sarcoidosis and relate the results to fungal exposure at home and clinical findings. Subjects with sarcoidosis (n=22) and controls (n=20) participated. Peripheral blood mononuclear cells were stimulated with soluble or particulate ß-glucan (S-glucan, P-glucan), chitin or lipopolysaccharide (LPS), whereafter tumour necrosis factor (TNF)-α, interleukin (IL)-6, IL-10 and IL-12 were measured. The severity of sarcoidosis was determined using a chest X-ray-based score. Serum cytokines (IL-2R, IL-6, IL-10 and IL-12) were determined. To measure domestic fungal exposure, air in the bedrooms was sampled on filters. N-acetylhexosaminidase (NAHA) on the filters was measured as a marker of fungal cell biomass. The induced secretion of cytokines was higher from peripheral blood mononuclear cells (PBMC) from subjects with sarcoidosis. P-glucan was more potent than S-glucan inducing a secretion. Chitin had a small effect. Among subjects with sarcoidosis there was a significant relation between the spontaneous PBMC production of IL-6, IL-10 and IL-12 and the NAHA levels at home. The P-glucan induced secretion of IL-12 was related to the duration of symptoms at the time of diagnosis. Their X-ray scores were related to an increased secretion of cytokines after stimulation with LPS or P-glucan. Subjects with sarcoidosis have a higher reactivity to FCWA in vitro and to home exposure. The influence of FCWA on inflammatory cells and their interference with the inflammatory defense mechanisms in terms of cytokine secretion could be important factors for the development of sarcoidosis.

Phagocytic activity in blood and proliferation of peripheral blood lymphocytes during the perinatal period in primiparous sows.

The objective of this study was to determine whether phagocytic activity in blood and proliferation of peripheral blood lymphocytes are impaired during perinatal period. The study comprised 18 primiparous sows (Landras × Large White) free from clinical signs of diseases. During the experiment blood samples were collected three times from each sow. Sampling was performed on three different dates, always from all sows at once. At the first date of sampling sows were 21 ± 3 days before parturition, at the second date ± 1 day around parturition time and at the third date 21 ± 3 days after parturition. Phagocytic activity of monocytes and granulocytes was assessed in heparinized whole blood with addition of fluorescein isothiocyanate (FITC)-labelled opsonized bacteria Escherichia coli and the percentage of phagocytes which have ingested bacteria was measured as fluorescence activity by flow cytometry. The percentage of phagocyting monocytes and granulocytes was lowest at parturition (72.6 ± 16.37, 52.4 ± 20.59) and significantly increased within the next 21 ± 3 days (86.5 ± 6.16, 69.89 ± 5.80). Similarly, the phytohemagglutinin (PHA) (10 µg/ml) stimulated in vitro lymphocyte response was suppressed by parturition in primiparous sows (p < 0.001).

Changes in sperm apoptotic markers as related to seminal leukocytes and elastase.

To elucidate the effects of inflammation on sperm quality, this study analysed classical sperm characteristics, leukocytes and elastase in neat semen, and sperm apoptotic markers, i.e. changes in plasma membrane phospholipid asymmetry, mitochondrial membrane potential (MMP), DNA integrity and intracellular reactive oxygen species (ROS), in semen prepared by density gradient using flow cytometry from 348 men of infertile couples. Increased leukocytes (> or = 0.1 x 10(6)/ml) were associated with a decreased sperm concentration, motility and normal morphology (P < or = 0.001). Sperm necrosis and DNA denaturation were increased (31.3 versus 26.6%, P=0.020; 15.5 versus 11.5%, P = 0.011, respectively), whereas spermatozoa with normal MMP were decreased (64.1 versus 70.0%, P=0.004). High leukocyte levels ((> or = 1 x 10(6)/ml) were not associated with any of the observed sperm parameters. At low elastase concentration (100-290 microg/l), DNA denaturation was higher (16.1 versus 10.5%, P = 0.024) compared with very low elastase concentration (< 100 microg/l). A high elastase concentration (290-1000 microg/l) was associated with higher ROS index compared with low elastase concentration (1.28 versus 1.01, P=0.016). Slightly increased leukocytes and elastase are associated with slightly poorer sperm characteristics and/or increased sperm necrosis, DNA denaturation and intracellular ROS and decreased MMP.

T lymphocyte activation and cytokine expression in periapical granulomas and radicular cysts.

INTRODUCTION: Radicular cysts (RCs) are periapical lesions resulting in jaw bone destruction. The inflammatory dental periapical granuloma (PG) is considered to be the origin of RC formation; however the mechanism of RC development remains unclear. METHODS: Cell suspension from the surgically extirpated tissue of 27 RCs and 25 PGs was obtained. Bacteriological analysis of the PG tissue samples was performed in order to define two major groups of PG according to the prevailing causative bacterial infection: the streptococcal PG (PG-S, n=10) and the anaerobe PG (PG-A, n=9) group. The inflammatory response of tissue infiltrating lymphocytes was assessed by following T lymphocyte activation (HLA-DR expression) as well as interferon gamma (IFN-gamma) and interleukin 4 (IL-4) production which were evaluated by the flow cytometry. RESULTS: In comparison to RC both types of PG contained a higher proportion of activated T cells (HLA-DR) and lower proportion of IL-4 producing cells. PG-A tissue contained increased percentage of CD3 cells and increased percentage of T helper 1 (Th1) cells in comparison with PG-S. In RC the IFN-gamma production is higher than in streptococcal PG-S but similar as in PG-A. DISCUSSION: Tissue infiltration by Th2 cells and IL-4 production is likely to play an etiopathogenic role in RC formation.

Lung tissue and tumour-infiltrating T lymphocytes in patients with non-small cell lung carcinoma and chronic obstructive pulmonary disease (COPD): moderate/severe versus mild stage of COPD.

Cytotoxic CD8+ T cells have been suggested to be key players in the pathogenesis of chronic obstructive pulmonary disease (COPD). We wanted to investigate the phenotype of lung tissue T lymphocytes (LTL) and tumour-infiltrating T lymphocytes (TIL) in smokers with peripheral non-small cell lung carcinoma (NSCLC) with moderate/severe versus mild COPD. Lung tissue and tumour samples were obtained from patients with moderate/severe stage of COPD (n = 10) and from patients with mild stage of COPD (n = 7) at lung resection for a solitary peripheral NSCLC, processed and analysed by flow cytometry. The flow-cytometric results showed that lung tissue T cells, regardless of the severity of COPD, were mostly of the activated phenotype, expressed the CXCR3 chemokine receptor characteristic of type 1 T cells, and did neither significantly differ in the expression of activation markers (CD69, CD25 and HLA-DR), differentiation markers (CD27 and CD28) and chemokine receptors (CXCR3 and CCR4) between the selected groups, nor showed any significant correlation with lung function measured as forced expiratory volume in 1 s (FEV1) or TLCO. Compared with LTL, a significantly greater proportion of TIL expressed the activation markers CD69 and CD25, but a lower proportion showed a fully differentiated CD27- 28- phenotype. We conclude that lung LTL patterns are similar in NSCLC patients with moderate/severe or mild stages of COPD, and are not significantly related to lung function. LTL and TIL possess different phenotype characteristics. The majority of tumour tissue T cells are activated, but it seems that their process of differentiation is incomplete.

Specific T cell responses to Helicobacter pylori predict successful eradication therapy.

OBJECTIVE: The aim of our prospective study was to test a specific T cell response to Helicobacter pylori before therapy and compare it to the success of H. pylori eradication 12 months later. METHODS: A total of 14 dyspeptic patients and 10 patients with previous H. pylori eradication failure were recruited into the study; before therapy their gastric samples for H. pylori cultivation and blood samples for dendritic cell cultivation were obtained. H. pylori antigens were produced to prime dendritic cells for stimulation of T lymphocyte response. RESULTS: The level of cytokine response by T cells was measured and results were compared with the success of H. pylori eradication one year later. There was a significantly increased response in expression of IFN-gamma and IL-4 molecules by DCs stimulated T cells in subjects that successfully eradicated H. pylori compared with those who failed to eradicate the infection. Our results support the hypothesis that successful H. pylori eradication requires established anti-H. pylori immune response besides antibiotic treatment. CONCLUSION: Effective IFN-gamma cytokine response to H. pylori antigens seems to be of particular importance. Immunisation could be therefore beneficial for H. pylori eradication, while immunodeficiency could cause the failure in H. pylori eradication.

Commensal oral bacteria antigens prime human dendritic cells to induce Th1, Th2 or Treg differentiation.

In various immunopathologic conditions, bacterial flora induce an immune response which results in inflammatory manifestations, e.g. periapical granuloma. Dendritic cells provide the main orchestration of specific immune responses. The aim of our study was to test the capacity of distinct oral bacterial antigens (prepared from Streptococcus mitis, Propionibacterium acnes, and Bacteroides spp.) to prime human dendritic cells for stimulation of the T-lymphocyte response. To assess the T-lymphocyte response, the expression of CD25, CD69, intracellular interferon gamma (cIFN-gamma), and intracellular interleukin 4 (cIL-4) was determined. Dendritic cells were prepared from leukocyte buffy coat from healthy blood donors. Monocytes were stimulated with IL-4 and GM-CSF and dendritic cells activated with bacterial lysates. Cell suspensions contained up to 90% dendritic cells, which represented 2-12% of the initial number of mononuclear cells. Lymphocyte subsets that developed in lymphocyte cultures after 1 week of stimulation were analyzed by flow cytometry. Dendritic cells, primed with antigens of Bacteroides fragilis have shown significantly higher activation and expression of intercellular IFN-gamma by T lymphocytes compared to negative controls. The dendritic cells primed with antigens of P. acnes had no effect on T-lymphocyte activation or cytokine production; instead they induced differentiation of T lymphocytes into CD25bright cells (regulatory T cells) with a potentially inhibitory effect on immune response. Dendritic cells primed with antigens of S. mitis induced increased expression of cIL-4. We conclude that commensal oral bacteria antigens prepared from B. fragilis, S. mitis, and P. acnes prime human dendritic cells to induce Th1, Th2, and T(reg) differentiation, respectively. This may advance our understanding of immunopathologic manifestations in the oral cavity and offer new possibilities for redirecting immune responses in mucosal vaccination.

Evaluation of separate vs pooled swab cultures, different media, broth enrichment and anatomical sites of screening for the detection of methicillin-resistant Staphylococcus aureus from clinical specimens.

Early identification of methicillin-resistant Staphylococcus aureus (MRSA) carriers is a major component of an MRSA control programme. The cost and laboratory workload could be markedly reduced by processing multiple swabs from one person in one culture broth (specimen pooling). We evaluated the sensitivity for MRSA detection and the growth rate of pooled swabs compared with individual processing. In total, 1254 swabs from 423 subjects (two to five swabs per subject) were submitted for detection of MRSA. Swabs were suspended in 2-mL volumes of sterile Todd-Hewitt Broth and divided into two 1-mL aliquots. One aliquot of the suspension was processed as a single specimen, and the other aliquot was mixed (pooled) with other suspensions in which swabs from the same patient were suspended. Forty-four (10%) pooled samples were positive for MRSA. Specimens from seven additional patients that were negative when pooled were positive when processed separately. There was no case where the pooled specimen was positive but the separate specimens were negative. The diagnostic sensitivity of pooled surveillance cultures compared with single cultures, when only subjects colonized by MRSA were considered, was 86% and the false-negative rate was 14%. Eighty percent of the pooled positive cultures were detected by the third day and all were detected by the fourth day. Fifty-four percent of the specimens processed separately were detected by the second day and all were detected by the fourth day. Pooling of specimens decreases the sensitivity of MRSA detection compared with processing each swab separately, particularly in swabs with a low number of colony-forming units. In all subjects whose pooled samples were negative but whose swabs examined separately were positive, the swabs examined separately were negative on primary plates and positive only after culturing in enrichment broth.

Influenza vaccination of human immunodeficiency virus 1-infected patients receiving antiretroviral therapy.

In 13 human immunodeficiency virus 1 (HIV-1) infected patients receiving a highly active antiretroviral therapy (HAART) annual influenza vaccination was conducted. It was hoped that HAART would prevent a post-vaccination increase in HIV-1 load and potential adverse effects. Only two patients had an increased viral load on day 14 post vaccination (p.v.). At 6 months p.v., the majority of the patients had a significantly increased CD4 cell count and a significantly decreased viral load. This indicates that HAART can protect patients from adverse consequences of influenza vaccination. The production of antibodies to the influenza A and B viruses in the HIV-infected patients was substantially lower than that in healthy persons. We propose that HIV-positive patients receiving HAART should be subjected to annual influenza vaccination.

The effects of medium-strength electric impulses on human blood.

Leukocyte subsets, total leukocyte isolates or full blood samples were subjected to medium-strength square-wave electric impulses (100 V/cm field force, 5 ms duration). On the surface of the leukocytes, the expressions of several markers (CD3, CD4, CD8, CD11a, CD11b and ICAM-1) were determined in order to study the influence of pulsed ionic currents on different aspects of the cellular immune response. Large individual differences were observed among randomly chosen healthy donors, both in the initial expression rate and in the response patterns of different antigens. As a general conclusion, it can be stated that electric impulses with the above parameters activate the state of immune response alertness of human leukocytes. Changes in the activities of several enzymes in the serum in response to electric impulses were also tested in order to examine the feasibility of ex vivo electric treatment of human blood for the establishment of an antiviral and immune activated condition. Slightly elevated lactate dehydrogenase (LDH) levels point to a possibility of enhanced haemolysis, while the lack of an elevation in the membrane-bound peroxidase activity indicates the absence of haemolysis. Significant rises were detected in the serum superoxide dismutase (SOD) activities. Since most ex vivo blood manipulations are characterised by the appearance of superoxide radicals in the serum, a SOD activity enhancement is considered beneficial in these cases. A mild, but significant reduction in the blood clotting time indicates that electric treatment of human blood should be performed with special attention to thrombosis-prone conditions, and adequate precautions and countermeasures should be introduced. Although wider examinations are required before this method can be fully recommended, ex vivo blood treatment with medium-strength electric impulses seems to be a promising adjuvant course for the establishment of acute immune potentiation and an antiviral state in patients undergoing dialysis treatment.

Immune response in lymphocyte cultures stimulated by oral bacteria preparations.

Lymphocyte cultures were used as an in vitro experimental model to get a deeper insight into immune response to oral bacteria in periapical granulomas. Lymphocytes isolated from leucocyte concentrate were in lymphocyte cultures stimulated by antigen preparations of oral bacteria. Lymphocyte subsets that have developed in lymphocyte cultures after a week of stimulation were analysed by flow cytometry. A significant increase in expression of INF-gamma molecules in CD3+ cells stimulated by antigen preparations of oral streptococci was found, compared with negative control. On the other hand we observed a significant increase in expression of IL-4 in CD3+ cells stimulated by antigens of anaerobic bacteria, compared with negative control. Our results show that antigens of oral streptococci in in vitro lymphocyte cultures induce the differentiation of T helper cells into Th2 cells and that antigen preparations of anaerobic bacteria induce the differentiation of T helper cells into Th1 cells. Furthermore, an increased expression of HLA-DR molecules on CD8+ T cells stimulated by antigens of oral streptococci was found, compared with negative control.

Immune response in chronic periapical parodonititis.

The purpose of our study was to investigate the immune response in chronical periapical parodontitis (CPP) by using multidisciplinary approach. 30 CPP samples were obtained after surgical removal--apicoectomy. Each CPP sample was examined by histological, bacteriological and flow cytometrical (FC) analysis of lymphocytes infiltrating CPP samples. Ten percent of bacteriological samples were sterile, others had significant aerobic and anaerobic growth. We used pathohistologic and microbiologic findings and compared them to the results of immunological analysis. By FC we found a significant increase in proportions of T lymphocytes expressing interleukin-2 receptors and ICAM-1 compared to peripheral blood lymphocytes. Proportions of T helper cells that produce interferon-gama (IFN-gamma) was higher in CPP samples predominantly colonized by anaerobic bacteria. There were no differences in IL-4 expression by T cells in both groups (anaerobic and streptococcal). Among anaerobic CPP samples differences in proportion of T cells that express IL-2 receptors expression was also found between samples colonised by P. acnes and Bacteroides sp. Oral streptococci cause relatively limited tissue destruction and induce Th2 type of immune response accompanied by non-cytotoxic inflammatory reaction. On the contrary, anaerobic bacteria induce Th1 type of immune response that cause more severe inflammatory reaction (type 4) of hypersensitivity that damage the tissue by the action of cytotoxic T cell activation.

Diminished Th1-type cytokine production in gastric mucosa T-lymphocytes after H. pylori eradication in duodenal ulcer patients.

Helicobacter pylori infects an estimated 50% of the world population, however only a small proportion of individuals develop clinical symptoms of gastritis, peptic ulceration or gastric cancer. The variations in disease presentation may be due to differences in bacterial virulence and/or immune response to the pathogen. In the previous study we reported an increased expression of the IL-2 receptor in duodenal ulcer (DU) patients infected with H. pylori. This study examined intracellular lymphokine production in gastric mucosa infiltrating T lymphocytes in DU patients before and after H. pylori eradication. T lymphocytes were isolated from gastric mucosa biopsies by using mechanical and enzymatic tissue desegregation. Ficoll-purified lymphocytes were incubated with monoclonal antibodies and analysed by using 3-colour flow cytometry analysis for intracellular interferon gamma (IFNgamma) and interleukin 4 (IL-4) expression in order to define Th1 and Th2 cell population. We demonstrated a significant decrease in the proportion of Th1 cells infiltrating gastric mucosa 6 and 12 months after H. pylori eradication. Our results suggest the importance of the local immune response in the development of H. pylori related gastritis.

A mouse model of chronic bacterial lesions (a cotton trap) for studying oral bacteria-lymphocyte interactions.

We established a mouse model of chronic bacterial infection (cotton trap) to get a deeper insight into interactions between immune cells and bacterial strains, that are most commonly isolated from periapical processes. We have used flow cytometry to identify the presence of intracellular cytokines of activated T cells collected from cotton traps, previously infected with different strains of bacteria and implanted subcutaneously into the back of the mice. We provide an evidence that anaerobic bacteria (Bacteroides sp.) and nocardiae are more effective in inducing cytotoxic immunity and Th1 response compared to oral streptococci. Differences in immune response against anaerobic bacteria when compared to streptococci are probably dependent on some non-specific immune cell stimulation (e.g. by bacterial cell wall components), nevertheless the role of specific antigen-dependent immune mechanism can not be excluded.

Conjunctival epithelium expression of HLA-DR in glaucoma patients and its influence on the outcome of filtration surgery.

AIMS: To analyse the expression of HLA-DR on conjunctival epithelial cells in patients with glaucoma taking topical antiglaucoma therapy. METHODS: 10 patients taking no topical medication and 30 patients with uncontrolled glaucoma taking medical therapy participated in the study. The specimens were obtained by impression cytology preoperatively, 3 months, and 6 months after filtration surgery. The expression of HLA-DR on T lymphocytes and epithelial cells was analysed by flow cytometry. RESULTS: A significant increase in HLA-DR on epithelial cells was found preoperatively in patients with glaucoma. A significant increased expression of HLA-DR on epithelial cells was detected 3 months and 6 months after surgery. CONCLUSIONS: The increased expression of HLA-DR on conjunctival epithelial cells still present 6 months after surgery indicates the increased ability of epithelial cells to induce immune inflammation with subsequent fibrosis.

Effect of epidural and intravenous clonidine on the neuro-endocrine and immune stress response in patients undergoing lung surgery.

The effects of intravenous and epidural clonidine, 4 microg kg-1, combined with epidural morphine, 40 microg kg-1, on the neuro-endocrine and immune stress responses to thoracic surgery are reported. A control group received only epidural morphine. Anaesthesia was induced and maintained with propofol. Catecholamines, vasopressin, cortisol, beta-endorphin concentrations and leucocyte counts were measured before drug administration, immediately after intubation of the trachea, after thoracotomy and at the end of surgery. Catecholamines did not change in any of the groups. The other stress hormones increased during surgery, the pattern being similar in the three groups. Total leucocyte and neutrophil counts were increased in all groups at the end of surgery, but the increase was least in the epidural clonidine group. The number of lymphocytes was reduced at the end of surgery in the epidural and intravenous group, compared with the control group in which the number of lymphocytes did not change. The effects are more pronounced with epidural than with intravenous administration. We conclude that clonidine can modulate the immune stress response to thoracic surgery.

Effectiveness of a simply designed tumor vaccine in prevention of malignant melanoma development.

We investigated the efficacy of a simple syngeneic tumor vaccine to induce specific antitumor immunity in female C57Bl/6 mice. Tumor vaccine was prepared by mixing irradiated B-16 melanoma tumor cells with the pleiotropic biological response modifier-maleic anhydride divinyl ether (MVE-2). Experimental animals were pretreated with the vaccine in order to prevent the development of intraperitoneal (i.p.) B-16 melanoma tumors after inoculation of viable tumor cells. More than 40% of prevaccinated animals challenged i.p. with 5 x 10(5) viable tumor cells were completely protected from tumor development and remained tumor-free 100 days after tumor cell inoculation. The percentage of tumor-free animals (survivors) rose to as much as 90% when the application of tumor vaccine was repeated two weeks after the first vaccination (i.e. one week after the inoculation of viable tumor cells). The induced antitumor response depended predominantly upon macrophage function, since vaccinated animals which were depleted of peritoneal macrophages died within the same time range as animals in the control group. Also, tumor-type specificity of the vaccine was confirmed by the fact that the animals vaccinated with B-16 melanoma vaccine were not protected from the development of another type of tumor. In conclusion, comparison of the experimental data with the data from the literature suggests that our simple tumor vaccine may be as effective as genetically engineered tumor vaccines. At the same time, this kind of vaccine is easier to control and thus safer to apply in humans when compared to genetically engineered vaccines.

Diminished interferon-gamma production in gastric mucosa T lymphocytes after H. pylori eradication in duodenal ulcer patients.

BACKGROUND/AIMS: Helicobacter pylori (H. pylori) infects an estimated 50% of the world population; however, only a small proportion of individuals develop clinical symptoms of gastritis, peptic ulceration or gastric cancer. The variations in disease presentation may be due to differences in bacterial virulence and/or immune response to the pathogen. In a previous study we reported an increased expression of the IL-2 receptor in duodenal ulcer (DU) patients. The present study examines the expression of IL-2 receptor and intracellular lymphokine production in gastric mucosa infiltrating T lymphocytes in DU patients before and after H. pylori eradication. METHODOLOGY: T lymphocytes were isolated from gastric mucosa biopsies by using mechanical and enzymatic tissue desegregation. Ficoll-purified lymphocytes were incubated with monoclonal antibodies and analyzed by using 4-color flow cytometry analysis for the IL-2 receptor (CD25) and intracellular interferon-gamma (IFN-gamma) and IL-4 expression. Lymphocytes from 24 H. pylori-infected patients with severe gastric mucosa infiltration (G2 and G3 histological type in Sydney classification) were analyzed. RESULTS: We demonstrated a significant decrease in IL-2 receptor expression on gastric mucosa T cells 3 and 12 months after eradication of H. pylori. We also demonstrated a diminished IFN-gamma production 3 and 12 months after H. pylori eradication. CONCLUSIONS: Our results suggest that cellular immune activation in gastric mucosa is reversibly dependent on the presence of H. pylori.