Chemokine scavenging by the human cytomegalovirus chemokine decoy receptor US28 does not inhibit monocyte adherence to activated endothelium

The human cytomegalovirus has found smart ways to exploit the chemokine network in order to subvert immune attack. Chemokines trigger the arrest and firm adhesion of inflammatory cells to the vascular wall. Scavenging of chemokines by viral decoy receptors, such as US28, might prevent arrest of leukocytes to the vascular wall and impair an antiviral immune response. We determined the effect of chemokine scavenging by endothelium-expressed signaling mute US28 (US28R129A) on static monocyte adhesion. Despite the chemokine scavenging capacity of US28R129A, expression of this construct by endothelial cells was insufficient to disrupt leukocyte adhesion to cytokine-activated monolayers. Our results suggest that the concentrations of chemokines that trigger firm leukocyte adhesion are too high to be efficiently scavenged by viral chemokine decoy receptors like US28. From the results of this experimental model a role for US28 in viral immune evasion by chemokine scavenging would appear therefore unlikely. (c) 2005 Elsevier B.V. All rights reserved.