The role of interleukin-4 (IL-4) in the inflammatory process has emerged recently. In this study, we investi-gated the effect of IL-4 on the angiogenic process in an in vitro experimental system. IL-4 significantly inhib-ited the proliferation of human umbilical vein endothelial cells (HUVEC) that was induced by the vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). VEGF- or bFGF-induced HUVEC chemotaxis was abrogated by the IL-4 treatment. In addition, the formation of tube-like structures by HUVEC in the presence of VEGF or bFGF was also severely down-regulated by IL-4. The inhibitory effects on the critical steps of angiogenesis were not observed with IL-6 that is abundantly found in the inflamed tissue. Our results suggest that IL-4 may play a regulatory role in normal physiology and provide the potential possibility for IL-4 as a thera-peutic agent in the intervention of angiogenesis-related diseases.

Keywords: bFGF, IL-4, VEGF., Angiogenesis