Recent studies suggest that interleukin-8 (IL-8) exerts a direct influence on several functions such as chemotaxis or proliferation of keratinocytes. Since the effects of IL-8 in skin are mediated through specific receptors, we have studied the keratinocyte IL-8 receptor characteristics. We could identify specific binding sites for IL-8 both in freshly separated and in cultured epidermal cells by flow cytometry. Neutrophil activating peptide-2 (NAP-2) displaced IL-8 with lower affinity. Pretreatment of the cells with tumor necrosis factor-alfa (TNF-alfa) or IL-1alfa resulted in a significant increase in IL-8 binding, which was probably due to up-regulation of the binding sites. To acquire more information on the biologic function of the receptor, the effect of IL-8 on the immune-associated cell-surface markers of keratinocytes was also studied. IL-8 induced a selective expression of HLA-DR antigen, but had no effect on the expression of other cell-surface antigens (CD11a, CD18, CD36 and CD54). HLA-DR induction by IL-8 shows that this cytokine has other biological properties than leukocytes activation. Since interferon-gamma (IFN-gamma) was the only cytokine so far shown to be able to induce HLA-DR antigen expression on keratinocytes, our finding that IL-8 is also capable of stimulating epidermal HLA-DR expression is an important novel finding, which may be of significance in the pathogenesis of inflammatory skin diseases.
|Number of pages||13|
|Publication status||Published - Dec 1 1994|
- skin immune system
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