International union of pharmacology. XXII. Nomenclature for chemokine receptors

Chemokine receptors comprise a large family of seven transmembrane domain G protein-coupled receptors differentially expressed in diverse cell types. Biological activities have been most clearly defined in leukocytes, where c hemokines coordinate development, differentiation, anatomic distribution, t rafficking, and effector functions and thereby regulate innate and adaptive immune responses. Pharmacological analysis of chemokine receptors is at an early stage of development. Disease indications have been established in h uman immunodeficiency virus/acquired immune deficiency syndrome and in Plas modium vivax malaria, due to exploitation of CCR5 and Duffy, respectively, by the pathogen for cell entry. Additional indications are emerging among i nflammatory and immunologically mediated diseases, but selection of targets in this area still remains somewhat speculative. Small molecule antagonist s with nanomolar affinity have been reported for 7 of the 18 known chemokin e receptors but have not yet been studied in clinical trials. Virally encod ed chemokine receptors, as well as chemokine agonists and antagonists, and chemokine scavengers have been identified in medically important poxviruses and herpesviruses, again underscoring the importance of the chemokine syst em in microbial pathogenesis and possibly identifying specific strategies f or modulating chemokine action therapeutically. The purpose of this review is to update current concepts of the biology and pharmacology of the chemok ine system, to summarize key information about each chemokine receptor, and to describe a widely accepted receptor nomenclature system, ratified by th e International Union of Pharmacology, that is facilitating clear communica tion in this area.