IL-13 SELECTIVELY INDUCES VASCULAR CELL-ADHESION MOLECULE-1 EXPRESSION IN HUMAN ENDOTHELIAL-CELLS

Previous studies with human umbilical vein endothelial cells (HUVEC) h ave shown that the cytokine IL-4 induces adherence of human eosinophil s, but not neutrophils, because of its ability to selectively induce s urface expression of vascular cell adhesion molecule-1 (VCAM-1). Becau se the cytokine IL-13 shares a number of biologic properties with IL-4 , we examined the effect of IL-13 on the expression and function of ad hesion molecules on HUVEC. Incubation of HUVEC for 4 to 48 h with IL-1 3 (0.1 to 15 U/ml) induced surface expression of VCAM-1, as detected b y indirect immunofluorescence and flow cytometry, without significantl y affecting expression of E-selectin or intercellular adhesion molecul e-1. The kinetics and maximal IL-13-induced expression of VCAM-1 were similar to those seen with IL-4. Treatment of HUVEC with an optimal co ncentration of IL-13 (15 U/ml for 24 h) induced adhesiveness for eosin ophils, but not for neutrophils, and adhesion was completely inhibited by mAb recognizing VCAM-1 or alpha 4 integrin (CD49d). These results demonstrate that IL-13, like IL-4, selectively stimulates HUVEC to exp ress functional cell surface VCAM-1 and suggest a possible role for IL -13 in promoting VCAM-1/alpha 4 integrin-dependent accumulation of eos inophils during allergic and other inflammatory reactions in vivo.