Abstract
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. According to its biochemical and biological properties EC-GRAM can be separated from other cytokines such as ETAF/-interleukin 1, interleukin 2, interferons, granulocyte colony-stimulating factor (G-CSF) and tumor necrosis factor (TNF). However, an antibody to human GM-CSF neutralized about 75% of the activity. These results indicate that EC-GRAM activity stimulating the generation of reactive oxygen species by granulocytes is probably due to GM-CSF.
Dokumententyp: | Zeitschriftenartikel |
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Fakultät: | Medizin |
Themengebiete: | 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit |
URN: | urn:nbn:de:bvb:19-epub-7786-0 |
ISSN: | 0340-3696 |
Dokumenten ID: | 7786 |
Datum der Veröffentlichung auf Open Access LMU: | 24. Nov. 2008, 16:47 |
Letzte Änderungen: | 04. Nov. 2020, 12:50 |