PubMed Health⌕ Search

Biomedical subjects

M Danner

Publications and source records attributed to M Danner.

11 recordsLinked to original sources
PubMed1988

Human granulocyte-macrophage colony stimulating factor: an effective direct activator of human polymorphonuclear neutrophilic granulocytes.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) was shown to modulate different granulocyte functions. In the present study we investigated the effect of purified and recombinant human GM-CSF, particularly on the oxidative metabolism of isolated human granulocytes. In addition, ultrastructural changes upon stimulation were evaluated. For detection of granulocyte activation the following assay systems were used: 1) lucigenin-dependent chemiluminescence (CL), 2) superoxide-dismutase (SOD) inhibitable cytochrome C-reduction (superoxide), 3) horseradish peroxidase-mediated oxidation of phenol red (hydrogen peroxide), 4) release of myeloperoxidase, 5) ultrastructural detection of hydrogen peroxide-production, and 6) scanning and transmission electron microscopy (SEM and TEM, respectively). A significant CL response was seen upon stimulation with recombinant human GM-CSF at concentrations ranging from 1 to 10(3) U/ml. The CL response started within 5-10 min with a maximum at 60-90 min and lasted more than 3 h. Thereafter granulocytes were completely deactivated to restimulation with the same mediator and with Tumor Necrosis Factor, but responded to other triggers of the oxidative burst, whereas the response to f-met-leu-phe was significantly increased. The CL signal was completely blocked by an antiserum to GM-CSF. Moreover, the response was significantly inhibited by SOD and D-Mannitol, suggesting the involvement of distinct reactive oxygen species (ROS) in generating the CL response. Significant amounts of superoxide were detected within 180 min after stimulation with GM-CSF, whereas release of hydrogen peroxide and peroxidase were only minimal as shown by functional and ultrastructural assays. Activation of granulocytes could be visualized by SEM and TEM. GM-CSF stimulated cells showed an increased adherence to the substratum developing polarized filopodia and an increased number of intracellular vesicles within 30 min after addition of the stimulus. The results clearly demonstrate that GM-CSF directly stimulates granulocytes and, particularly, their oxidative metabolism. Therefore, GM-CSF which is probably released by epidermal cells appears to be a candidate for neutrophil activation in the skin, and thereby may play a crucial role in inflammatory skin diseases.

Chemotaxis↗
PubMed1987

Granulocyte-activating mediators (GRAM). II. Generation by human epidermal cells--relation to GM-CSF.

In the present study we investigated the capability of human epidermal cells to generate granulocyte-activating mediators (GRAM). It could be shown that human epidermal cells as well as an epidermoid carcinoma cell line (A431) produce an epidermal cell-derived granulocyte-activating mediator (EC-GRAM) which stimulates human granulocytes to release significant levels of toxic oxygen radicals as measured by a lucigenin-dependent chemiluminescence (CL). For further characterization of EC-GRAM the A431 cell line was used. Supernatants of A431 cells usually contained maximal EC-GRAM levels within 24 h of incubation. Factor production was enhanced by bacterial lipopolysaccharide (LPS), but not by silica particles and PHA. Moreover, freeze-thaw lysates of A431 cells and extracts of heat-separated human epidermis contained significant levels of EC-GRAM. Preincubation of granulocytes with EC-GRAM resulted in an enhanced response to subsequent stimulation with the chemotactic peptide f-met-phe. In contrast EC-GRAM did not affect the response to PMA or zymosan particles. However, EC-GRAM treated granulocytes were unresponsive to restimulation with EC-GRAM. Upon high performance liquid chromatography (HPLC) gel filtration EC-GRAM eluted within two major peaks exhibiting a molecular weight of 17 kD and 44 kD.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological Products↗
PubMed1987

Human keratinocytes and epidermoid carcinoma cell lines produce a cytokine with interleukin 3-like activity.

Keratinocytes are capable of releasing distinct immunomodulating cytokines such as epidermal cell-derived thymocyte activating factor (ETAF) and an epidermal cell-derived natural killer cell augmenting factor (ENKAF). The present study was performed to determine whether human keratinocytes also may secrete an interleukin 3 (IL-3)-like mediator and thereby participate in the regulation of mast cell activity in the skin. Supernatants of freshly isolated human epidermal cells (EC) and malignant keratinocyte cell lines (A 431, SCC) were tested for their capacity to induce the proliferation of IL-3-dependent cell lines 32 DCL and FDCP. Human epidermal cell interleukin 3 (EC IL-3) is spontaneously released by freshly isolated EC, A 431, and squamous cell carcinoma (SCC) cells. However, both normal EC and A 431 cells produced increased levels of EC IL-3 activity when cultured in the presence of different stimulants, such as phorbol myristate acetate and lipopolysaccharide. The EC IL-3 activity was not inhibited when treated with a monoclonal anti-IL-1 or anti-IL-2-antibody. Biochemical characterization showed that human EC IL-3 has a molecular weight of 17K, elutes of DEAE-ion exchange high-performance liquid chromatography (HPLC) as one major peak at 0.36 M NaCl, and upon HPLC-chromatofocusing exhibits 3 isoelectric points of 7.8, 7.5, and 5.6. Upon reversed-phase HPLC, EC IL-3 activity eluted at about 100% acetonitrile. When highly purified EC IL-3 was labeled with 125I and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a single homogeneous band exhibiting a molecular weight of 17K was seen, which correlated with the IL-3 activity and was free of ETAF/IL-1, IL-2, and interferon activity. These data indicate that human EC synthesize an IL-3-like cytokine which is distinct from ETAF/IL-1, IL-2, and interferon and thereby may participate in the regulation of mast cell activity during inflammatory and fibrotic, as well as hypersensitivity reactions.

Breast Neoplasms↗
PubMed1986

Characterization of a monoclonal antibody directed against the biologically active site of human interleukin 1.

Human IL-1 was successfully used to produce an anti-IL-1 mAb. Anti-IL-1 (IgG2a) blocked IL-1-mediated thymocyte and fibroblast proliferation, but did not interfere with the biological effects of other lymphokines, such as IL-2 or IL-3. The antibody immunoprecipitated biosynthetically radiolabeled 33, 17, and 4 kD IL-1. An immunoadsorbent column yielded 20% of initial activity, and upon HPLC size-exclusion chromatography, affinity-purified IL-1 had a molecular mass of approximately 4 kD. These results provide first evidence of a monoclonal anti-IL-1 that reacts with different species of IL-1 and apparently binds to an epitope close to the active site of IL-1. Thus, anti-IL-1 IgG may be very helpful for further investigations of the molecular as well as biological characteristics of IL-1 and related mediators.

Animals↗
PubMed1986

Monoclonal anti-IL 1 is directed against a common site of human IL 1 alpha and IL 1 beta.

Cytokines exhibiting interleukin 1 (IL 1) activity are known as important mediators of immunity and inflammation. Therefore, the ability of a monoclonal anti-IL 1 antibody to neutralize and bind IL 1 was investigated. Anti-IL 1 IgG blocked the IL 1-mediated thymocyte and fibroblast proliferation and also inhibited the biological activity of epidermal cell-derived thymocyte activating factor (ETAF), but did not affect interleukin 2 (IL 2) and interleukin 3 (IL 3) activity. Monoclonal anti-IL 1 blocked the activity and bound to both human IL 1 alpha and IL 1 beta. Additionally using anti-IL 1, it was possible to immunoprecipitate 31 kD, 17 kD and 4 kD biosynthetically radiolabeled biologically active species of IL 1. These data indicate that IL 1 alpha and IL 1 beta share a common site which is responsible for the biological activity. Moreover, this part of the IL 1 molecule also appears to be located within the low mw 4 kD break-down product. Since anti-IL 1 also was capable to detect surface bound IL 1 on LPS-stimulated mononuclear adherent cells, the antibody may help to elucidate the role of surface IL 1 during an immune response. In addition, anti-IL 1 IgG may be very helpful to investigate the in vivo role of IL 1 during the pathogenesis of inflammatory diseases.

Antibodies, Monoclonal↗
PubMed1985

Characterization of immunoregulatory cytokines produced by epidermal cells.

The epidermis has been identified as an important site for the initiation of immunological events. In addition to the macrophage-like Langerhans cells, keratinocytes within the epidermal cells have been shown to act as immunoregulatory cells through the secretion of cytokines such as epidermal cell-derived thymocyte-activating factor (ETAF) and interleukin 3. Epidermal cell-derived interleukin 3 (EC IL-3), like lymphocyte-derived IL-3, induced the proliferation of IL-3-dependent mast cell-like cell lines. Biochemically, EC IL-3 was a heat-stable protein with a molecular weight of approximately 30 kD. Upon chromatofocusing, EC IL-3 exhibited three isoelectric points, at pI 7.8, 7.4, and 7.1. Furthermore, an antiserum against IL-3 neutralized EC IL-3 activity, suggesting that the molecules are closely related and share similar epitopes. ETAF-like macrophage-derived interleukin 1 (IL-1) is a low molecular weight protein with a multiplicity of amplifying effects on immunological and inflammatory reactions. Thus BALB/c mice were immunized with partially purified IL-1, and immune spleen cells were hybridized with plasmocytoma cells. Supernatants of the hybridoma cultures were screened for their capacity to inhibit IL-1-induced thymocyte proliferation. After expansion and cloning, one clone was selected for ascitic antibody production. The monoclonal anti-IL-1 antibody inhibited both the IL-1-dependent thymocyte and the fibroblast proliferation. Furthermore, the antibody blocked murine and human ETAF activity, suggesting that ETAF and IL-1 share antigenically similar domains. Moreover, by using the monoclonal antibody bound to Staphylococcus aureus cells, it was possible to immunoprecipitate IL-1. In contrast, anti-IL-1 antibody did not inhibit IL-2 or IL-3 activity. These findings demonstrate that the production of immunoregulatory cytokines is not confined to cells of the immune system and that keratinocytes through the production of ETAF and EC IL-3 may mediate inflammatory and hypersensitivity reactions. Furthermore, the monoclonal anti-IL-1 antibody may provide a useful tool for the development of new immunoassays to detect IL-1/ETAF and thereby facilitate the investigation of the role of these cytokines during the pathogenesis of inflammatory diseases.

Animals↗
PubMed1977

[Effect of air-electric fields on driving and reaction patterns. Test subjects in the car driving simulator (author's transl)].

In the relevant frequency range of about 10 Hertz cars can be considered very largely as Faraday cages and consequently as screens against air-electric fields. This may have a negative influence on driving and reaction patterns as a result. In an extensive investigation 48 subjects in a driving simulator were exposed to definite artificially produced air-electric fields. The self-rating of the performance and concentration of the subjects, reaction times and driving errors were determined. While the reaction times remained practically constant, the driving behavior of the subjects improved.

Adolescent↗