Endothelial adhesion molecule expression in an in vitro model of inflammation

Background: Cytokines influence the expression of adhesion molecules and hence, regulate the passage of leucocytes from the blood to the site of inflammation causing leucocyte accumulation and the modulation of the nature and progression of inflammatory responses. They form a complex communication network causing results which are not determined by the effects of a single cytokine but especially by the interaction of several cytokines. Method: For the determination of adhesion molecule expression on the surface of enzymatically detached endothelial cells, flow cytometry is applied. Fluorescence-conjugated mouse monoclonal antibodies directed against VCAM-1, ICAM-1, PECAM-1, CD34, E- and P-selectin are used. Results: We clearly demonstrate that ICAM-1, PECAM-1, P-selectin and CD34 are-in relation to an incubation cocktail containing solely TNF-alpha, IL-1beta and IFN-gamma-altered antagonistically by the supplementary addition of the inflammatory cytokines IL-2 and IL-6 as well as the anti-inflammatory cytokines IL-4 and IL-10, whereas VCAM-1 is synergistically enhanced under the same test conditions. Conclusion: The results of our in vitro investigations show that the effects of a single cytokine within a multicomponent cytokine combination on endothelial adhesion molecule expression are strongly influenced by the nature of the other cytokines present in the combination tested. (C) 2002 Elsevier Science B.V. All rights reserved.