ISSN:
1432-069X
Keywords:
Tumor necrosis factor-alpha
;
Keratinocyte cultures
;
Class II antigens
;
Cell Adhesion molecules
;
Immunoelectron microscopy
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The effects of recombinant human tumor necrosis factor-alpha (TNF) on cell proliferation, cell morphology, and on the expression of class II alloantigens and intercellular adhesion molecule-1 (ICAM-1) were assessed in human keratinocytes cultured in serum-free medium. TNF inhibited cell proliferation in a time- and dose-dependent manner with a minimum effective dose of 10 U/ml and a 50% inhibitory dose of 100 U/ml. However, TNF did not induce cell death, and the growth inhibition induced by TNF was completely reversible after its withdrawal. In vitro combination of TNF with interferon-alpha (IFN-alpha) and IFN-beta resulted in additive growth inhibitory effects, while IFN-gamma enhanced the TNF mediated growth inhibition in a synergistic way. Furthermore, TNF altered the morphology of the growing keratinocytes inducing the appearance of a fusiform, fibroblast-like population. Also, treatment with TNF over 6 days markedly induced the expression of ICAM-1 on the cultured keratinocytes with a minimal effective dose of 10 U/ml, while HLA-DR was only moderately expressed after 1,000 U/ml. TNF did not induce HLA-DQ, but reduced the IFN-gamma induced expression of HLA-DR and HLA-DQ. By immunoelectron microscopy, an intense membrane-bound labeling for ICAM-1 was found after treatment with TNF, clearly pronounced in areas of microvillous membrane protrusions. These results indicate that epidermal keratinocytes are a major target for various biological effects of TNF. We also found that TNF differentially modulates IFN-gamma-induced effects, thus suggesting its potential role in the regulation of inflammatory skin disorders.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00371643
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