ABSTRACT
Chemokines are structurally related, proinflammatory peptides that chemoattract and activate leukocytes by binding to G protein-coupled receptors. Two distinct subfamilies of chemokines, CC and CXC, can be distinguished based on conserved sequence motifs, and cDNAs for five leukocyte receptors restricted to one or more CC or CXC chemokines have been cloned (CXC restricted: interleukin-8 receptors A and B; CC restricted: the MIP-1α/RANTES receptor, and MCP-1 receptors A and B). Open reading frames (ORF) encoding functional chemokine receptors have also been identified in two herpesviruses. A receptor selective for the CXC chemokines interleukin-8, GROα and NAP-2 is encoded by ORF ECRF3 of Herpesvirus saimirí, and a receptor selective for the CC chemokines MIP-1α, MIP-1β, RANTES and MCP-1 is encoded by ORF US28 of human cytomegalovirus. Viral and mammalian chemokine receptor sequences are similar, suggesting a common origin. Delineation of the precise biologic functions of viral chemokine receptors may lead to new insights into the molecular pathogenesis of the corresponding viral infections, and may point to novel physiologic functions for mammalian chemokine receptors.
