Viral regulation of RANTES expression during human cytomegalovirus infection of endothelial cells

Human cytomegalovirus (HCMV) evades healthy immune responses during infecti on, and this evasion may allow HCMV to establish latency in the host. The h uman vasculature has been recognized as a site of HCMV infection and may al so be a site of latent HCMV infection. As the interface between circulating cells and underlying parenchymal cells, the vascular endothelium provides signals for local reaction of inflammatory cells. We propose that HCMV down -regulates expression of the proinflammatory chemokine RANTES from the infe cted endothelium, which may result in reduced recruitment of mononuclear ce lls to the site of infection. Abortive HCMV infection of primary endothelia l cells with the clinical isolate HCMV 4010, under conditions in which vira l gene expression could not occur, induced high levels of RANTES expression . Replicative HCMV infection, however, induced cells in parallel cultures t o express significantly lower levels of RANTES. Expression of the chemokine s interleukin 8 and MCP-1 by endothelial cells was found to be unaffected b y replicative HCMV infection and thus may not play an important role during early HCMV infection of the endothelium. HCMV may regulate RANTES expressi on from endothelial cells as a mechanism to evade the local immune response to infection.