CDB15:0000201 CCL16 — CCR2
Experimentally validated in Human; Orthology-inferred in Frog, Zebrafish, Chicken, Macaque, Pig, Dog, Cow, Chimp, Horse, Marmoset, Sheep
Title
Journal:; Year Published:
Abstract
Human CC chemokine liver-expressed chemokine/CCL16 is a functional ligand for CCR1, CCR2 and CCR5, and constitutively expressed by hepatocytes.
International immunology, 2001; PubMed, Homo sapiens CCL16 — Homo sapiens CCR2
ABSTRACT: Liver-expressed chemokine (LEC)/CCL16 is a human CC chemokine selectively expressed in the liver. Here, we investigated its receptor usage by calcium mobilization and chemotactic assays using mouse L1.2 pre-B cell lines stably expressing a panel of 12 human chemokine receptors. At relatively high concentrations, LEC induced calcium mobilization and chemotaxis via CCR1 and CCR2. LEC also induced calcium mobilization, but marginal chemotaxis via CCR5. Consistently, LEC was found to bind to CCR1, CCR2 and CCR5 with relatively low affinities. The binding of LEC to CCR8 was much less significant. In spite of its binding to CCR5, LEC was unable to inhibit infection of an R5-type HIV-1 to activated human peripheral blood mononuclear cells even at high concentrations. In human liver sections, hepatocytes were strongly stained by anti-LEC antibody. HepG2, a human hepatocarcinoma cell line, was found to constitutively express LEC. LEC was also present in the plasma samples from healthy adult donors at relatively high concentrations (0.3--4 nM). Taken together, LEC is a new low-affinity functional ligand for CCR1, CCR2 and CCR5, and is constitutively expressed by liver parenchymal cells. The presence of LEC in normal plasma at relatively high concentrations may modulate inflammatory responses.
A highly selective CCR2 chemokine agonist encoded by human herpesvirus 6.
The Journal of biological chemistry, 2003; PubMed, Homo sapiens CCL16 — Homo sapiens CCR2
ABSTRACT: The chemokine-like, secreted protein product of the U83 gene from human herpesvirus 6, here named vCCL4, was chemically synthesized to be characterized in a complete library of the 18 known human chemokine receptors expressed individually in stably transfected cell lines. vCCL4 was found to cause calcium mobilization as efficiently as the endogenous chemokine ligand CCL2 through the CCR2 receptor, whereas the virally encoded chemokine did not affect any of the other 17 human chemokine receptors tested. Mutual cross-desensitization between CCL2 and vCCL4 was demonstrated in the CCR2-transfected cells. The affinity of vCCL4 for the CCR2 receptor was 79 nm as determined in competition binding against radioactively labeled CCL2. In the murine pre-B lymphocyte cell line L1.2 stably transfected with the CCR2 receptor, vCCL4 acted as a relatively low potency but highly efficacious chemoattractant being equally or more efficacious in causing cell migration than CCL2 and CCL7 and considerably more efficacious than CCL8 and CCL13. It is concluded that human herpesvirus 6 encodes a highly selective and efficacious CCR2 agonist, which will attract CCR2 expressing cells, for example macrophages and monocytes, conceivably for the virus to infect and to establish latency in. It is suggested that vCCL4 during reactivation of the virus in for example monocyte-derived microglia could perhaps be involved in the pathogenesis of the CCR2-dependent disease, multiple sclerosis.