Helicobacter pylori induces the release of alpha-defensin by human granulocytes.

OBJECTIVES: Little information is available on the potential role of alpha-defensins derived from neutrophils during H. pylori infection, or the effect of H. pylori on the alpha-defensin release. The effects of H. pylori on human granulocytes were investigated in vitro by flow cytometry and ELISA. Additionally we sought to identify by immunohistochemistry the alpha-defensins within the gastric mucosa of patients infected with H. pylori. MATERIALS AND METHODS: The intracellular expression of alpha-defensin in human granulocytes and in mononuclear cells was determined by flow cytometry. Induction of alpha-defensin release from granulocytes, mononuclear cells, or from whole blood cultures by H. pylori was detected by measuring the HNP1-3 (alpha-defensin) concentrations in the supernatants by ELISA. Immunohistochemistry was used to identify HNP1-3 in infiltrating neutrophils in the gastric mucosa of eight patients. RESULTS: A considerable intracellular alpha-defensin staining was observed in granulocytes. Stimulation of granulocytes with H. pylori resulted in a decrease in intracellular staining which was due to the extracellular release of alpha-defensin. In whole blood cultures H. pylori infection resulted in significantly high alpha-defensin concentrations (131623 +/- 13986 pg/ml), which were mainly due to the activity of the granulocytes with only a minor amount furnished by the mononuclear cells. In H. pylori-infected mucosa, infiltrating neutrophils showed intense immunostaining with anti-HNP1-3. The intensity of alpha-defensin staining varied parallel with the density of H. pylori in the biopsy samples. CONCLUSIONS: H. pylori induce alpha-defensin release from granulocytes which may well be important in local host response to H. pylori infection in gastroduodenal diseases.

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.

Reversal of multidrug resistance by amitriptyline in vitro.

Amitriptyline, a tricyclic antidepressant, was able to reverse the multidrug resistance efflux pump of human colon cancer subline SW 620 and multidrug resistant (mdr) mouse lymphoma cells by decreasing rhodamine 123 efflux. The inhibitory effect of amitriptyline on the efflux pump was dose dependent. An investigation was made of the effects of mouse tumour necrosis factor (TNF) alpha and interferon (IFN) gamma on the efflux pump activity of mdr cells together with amitriptyline compared to the par cells (mdr-). After long-term cytokine pretreatment of mdr cells, the amitriptyline was more effective, due to some synergism between the amitriptyline and TNF-alpha.

Relevance of ICAM-1 to alcoholic liver cirrhosis.

An elevated serum concentration of soluble intercellular adhesion molecule-1 (sICAM-1) was observed in patients with alcoholic liver cirrhosis in strong correlation with the current activity of the liver disease and the history of alcohol consumption. Circulating ICAM-1 levels were significantly elevated in the sera of all of 25 patients (1,400 +/- 850 ng/ml) compared with normal healthy subjects. The highest levels of sICAM-1 (2,650 +/- 560 ng/ml) were measured in those patients who suffered from superimposed acute alcoholic hepatitis (SAH). Regularly drinking cirrhotic patients without SAH also exhibited significantly higher results than those who had stopped drinking. The serum ICAM-1 concentration showed a negative correlation with the duration of abstinence. No elevated sICAM-1 was found in ascitic fluid of cirrhotic patients, which tends to discount a significant intraperitoneal production of this molecule. flow cytometric analysis revealed an increased expression of ICAM-1 molecules on peripheral blood monocytes of cirrhotic patients. Proliferating bile ducts and parenchymal cells of cirrhotic livers displayed a positive ICAM-1 immunohistochemical reaction in 3 autopsy cases. It is concluded that the elevated levels of sICAM-1 in the serum of patients with alcoholic liver diseases may provide useful diagnostic or prognostic information. However, determination of the exact source of circulating ICAM-1 in patients with alcoholic cirrhosis still demands further investigations.

Interleukin-8 induces HLA-DR expression on cultured human keratinocytes via specific receptors.

Recent studies suggest that interleukin (IL)-8 exerts a direct influence on several functions such as the chemotaxis or proliferation of human keratinocytes (HK). Since the effects of IL-8 in skin are mediated through specific receptors, we have studied the characteristics of the keratinocyte IL-8 receptor. We could identify specific binding sites for IL-8 in cultured HKs by flow cytometry. Pretreatment of the cells with tumor necrosis factor (TNF)-alpha or IL-1 alpha resulted in a significant increase in IL-8 binding. IL-8 selectively induced expression of HLA-DR antigen, but had no effect on the expression of other cell surface antigens (CD11a, CD18, CD36 and CD54).

Inhibition of tumor necrosis factor production and ICAM-1 expression by pentoxifylline: beneficial effects in sepsis syndrome.

Tumor necrosis factor (TNF) has a pivotal role in the pathogenesis of sepsis and septic shock. Suppression of its biosynthesis might therefore be one of the strategies in the treatment of sepsis. When peripheral white blood cells were stimulated with either E. coli lipopolysaccharide (LPS) or Staphylococcus aureus, pentoxifiline (PTX) inhibited TNF production. In contrast, only a moderate inhibitory effect was observed on the induction of interleukin 6 (IL-6). PTX inhibited not only the TNF production of monocytes, but also the TNF secretion of both granulocytes and unseparated whole blood. The in vitro TNF and IL-6 producing capacities were higher in septic patients (n = 31) than in healthy blood donors (n = 15). Administration of PTX (400 mg/day) to 20 of the septic patients resulted in TNF production similar to that found in healthy controls. It also subsequently led to an improvement of the clinical status classified by the APACHE II score. The soluble intercellular adhesion molecule-1 (sICAM-1) level was significantly higher in the sera of septic patients before PTX treatment (800-1200 ng/ml) than in normal individuals (50-150 ng/ml), but it decreased following PTX therapy. Cytofluorometric analysis revealed that the expression of ICAM-1 on stimulated mononuclear cells was inhibited by PTX. It is presumed that the suppressive effect of pentoxifylline on TNF production may be of clinical importance, improving the therapeutic strategies in septic syndrome.

Effects of pentoxifyllin and PentaglobinO on TNF and IL-6 production in septic patients.

Pentoxifylline inhibited the TNF production of purified human white blood cells and whole blood cultures stimulated either by LPS or by Staphylococcus aureus. PTX did not influence the CD14 expression. The in vitro TNF and IL-6-producing capacities of septic patients were higher than in the control group. Administration of PTX to septic patients resulted in the normalization of TNF synthesis and in a moderate decrease in IL-6 production. It also subsequently led to an improvement in the clinical status. A further improvement in APACHE II score could be achieved by administration of PentaglobinO (Biotest). The prevention of in vitro TNF production by PentaglobinO could be demonstrated involving the use of whole blood rather than purified lymphocytes. The level of soluble ICAM-1 in the serum of septic patients was significantly higher than in normal individuals, but it decreased following PTX and PentaglobinO therapy. It is presumed that PTX and PentaglobinO can antagonize cytokine production at different levels, resulting in synergistic action that is beneficial in the treatment of sepsis.

Effects of amino and imino acridines on tumor necrosis factor production by human leukocytes.

Tumor necrosis factor (TNF) is a multifunctional cytokine with diverse effects on different cells and tissues. The biological activity of TNF is described on the basis of its cytotoxic action in vivo and in vitro. Different acridines were systematically synthesized and their effects were tested on endotoxin and Staphylococcus aureus-induced TNF production by human leukocytes. 9-aminobutylacridine and 9-ethylaminoacridine totally abrogated the TNF production of leucocytes at a concentration of 3.5 microM, whereas 9-imino -10-butylacridine and 9-imino-10-ethylacridine exerted only a 50% inhibition in the same concentration. Derivatives designated as 9-amino-(2-dimethylamino-ethyl)-acridine and 9-imino-10-(2-dimethylamino-ethyl)-acridine in a concentration of 7 microM exerted only a 30% and a 10% inhibition respectively. A significant modulation of TNF production was not observed when other alkylated derivatives in this series were applied. The TNF-mediated cytotoxic effect of monocytes against WEHI cells was also reduced by the most effective compounds. The acridines did not interfere with the expression of CD 14 molecules on monocytes. The exact mechanism of the suppression of TNF synthesis by acridines remains to be elucidated, but might be useful in the screening and evaluation of their anticancer properties and antimalarial effects.

Effect of phytohaemagglutinin on CD45 in T cells.

In this study the effect of PHA activation on the phosphatase activity of CD45 has been investigated in human leukemic T-cell lines. It has been found that in vivo activation of the cells with PHA resulted in 2-4-fold increase in enzyme activity. Addition of PHA to the postnuclear supernatant of cell lysates also resulted in elevation of phosphatase activity. Elevation of enzyme activity resulted from an increase in the amount of antigen in the immunoprecipitates. Elevation of the quantity was not the result of a de novo protein synthesis since the presence of cycloheximide, a protein synthesis inhibitor, did not modulate the effect of PHA. The effect of PHA was specific since ConA, that also bound to the CD45 molecules, or crosslinking of the antigen by antibody did not affect CD45. Since direct binding of PHA to CD45 molecules was shown in immunoblotting analysis, we suggest that the effect of PHA is a consequence of a PHA-induced conformational change of CD45 that results in up-regulation of the analyzed CD45 epitopes.

Multiple effects of promethazine in Staphylococcus aureus.

The antibiotic resistance of 6 Staphylococcus aureus strains was eliminated with a frequency from 1.2 to 10% in the presence of subinhibitory concentrations of promethazine. The pigment production of the cells was also eliminated by the promethazine to an extent of 0 to 5%. The cell size was increased and the protein A production was markedly decreased in S. aureus cells cultured in the presence of promethazine. Complex formation between protein A and promethazine was detected by differential spectrophotometry. The biological activity of staphylococcus protein A was abolished by promethazine in the passive haemagglutination of rabbit antiserum treated sheep red blood cells. Evidence has been found that plasmid-encoded functions of S. aureus cells can be altered in the presence of promethazine, and the chromosomally controlled synthesis of protein A, one of the weakest virulence factor of S. aureus is also lowered by promethazine.

Expression of human sialophorin (CD43) in a human x mouse somatic cell hybrid.

We have studied the expression of the human sialophorin (CD43) molecule in a human x mouse somatic cell hybrid (H-8). The CD43 molecule was detected on the cell surface by immunofluorescence analysis and the hybrid cell possessed human chromosome 16 which carries the gene for CD43. Biochemical analysis showed that the cell line expressed a low molecular form of CD43, which was due to altered glycosylation. The cells reacted with anti-CD43 antibodies but behaved differently in response to the antibodies in the aggregation process. This indicates the crucial importance of the sugar moieties and epitope position in aggregation and subsequent activation mediated by CD43.