Effects of interleukin-1, -2, -4, -6, interferon-gamma and granulocyte/macrophage colony stimulating factor on human vascular endothelial cells.

Human vascular endothelial cells (HUVEC) exhibit various immunological functions, i.e. expression of HLA class-II antigens after incubation with IFN-gamma or antigen presenting function. It has also been reported that HUVEC are able to produce IL-1, IL-6, GM-CSF and immunologically active cleavage products of arachidonic acid. In our study we investigated whether various cytokines, namely IL-1, IL-2, IL-6, GM-CSF and IFN-gamma, do alter the proliferative capacity of HUVEC, the production of van Willebrandt factor (vWF) and the expression of MHC class-II antigens. HUVEC were prepared by the collagenase digestion of human umbilical veins. Monolayers of cells were incubated with cytokines in different concentrations for 24 and 48 h. IFN-gamma inhibits the HUVEC [3H]thymidine uptake in a dose-dependent manner. Suppression of proliferation (40.1%) could be observed after 24 h incubation with 100 U IFN-gamma/ml. IL-1 was a more effective inhibitor of HUVEC proliferation (54% at 10 U/ml and 24 h incubation and 48.4% after 48 h) than IFN-gamma. IL-6 and GM-CSF showed an increasing effect on proliferation with 226% and 151% of the control group, respectively. IFN-gamma after an incubation period of 12 h and IL-1 after 24 h reduced the vWF content by about 30%. Bright MHC class-II expression was induced only by IFN-gamma. In conclusion, some of the immunoregulative cytokines might play an important role in the control of HUVEC proliferation.