The CC chemokine receptor-1 (CCR1) is a prime therapeutic target for treating autoimmune diseases. Through high capacity screening followed by chemical optimization, we identified a novel non-peptide CCR1 antagonist, R-N-[5-chloro-2-[2-[4-[(4-fluorophenyl)methyl]-2-methyl-1-piperazinyl]-2-oxoethoxy]phenyl]urea hydrochloric acid salt (BX 471). Competition binding studies revealed that BX 471 was able to displace the CCR1 ligands macrophage inflammatory protein-1␣ (MIP-1␣), RANTES, and monocyte chemotactic protein-3 (MCP-3) with high affinity (K i ranged from 1 nM to 5.5 nM). BX 471 was a potent functional antagonist based on its ability to inhibit a number of CCR1-mediated effects including Ca 2؉ mobilization, increase in extracellular acidification rate, CD11b expression, and leukocyte migration. BX 471 demonstrated a greater than 10,000-fold selectivity for CCR1 compared with 28 G-protein-coupled receptors. Pharmacokinetic studies demonstrated that BX 471 was orally active with a bioavailability of 60% in dogs. Furthermore, BX 471 effectively reduces disease in a rat experimental allergic encephalomyelitis model of multiple sclerosis. This study is the first to demonstrate that a non-peptide chemokine receptor antagonist is efficacious in an animal model of an autoimmune disease. In summary, we have identified a potent, selective, and orally available CCR1 antagonist that may be useful in the treatment of chronic inflammatory diseases.It is clear that the inappropriate interaction of immune cells, such as T lymphocytes and monocytes, can lead to extensive inflammation and tissue destruction, which is a hallmark of several autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. Immune cells are sent on their destructive journey by chemoattractant molecules known as chemokines, which interact with and signal through specific cell surface chemokine receptors. Chemokine receptors belong to the GPCR 1 superfamily and have been viewed as attractive therapeutic targets by the pharmaceutical industry mainly because of their central role in regulating leukocyte trafficking. The premise that drugs that can inhibit the directed migration and activation of immune cells could be useful therapeutically has prompted the search for specific and highly potent chemokine receptor antagonists.Autoimmune diseases like multiple sclerosis and rheumatoid arthritis are characterized by interactions between invading T lymphocytes and tissue macrophages that result in extensive inflammation, tissue damage, and chronic disease pathologies. Numerous studies have demonstrated CCR1 expression in these cell types, and a variety of evidence provides strong in vivo concept validation for a role of this receptor in animal models of these diseases. For example, Karpus et al. (1, 2) were able to show in a mouse EAE model of multiple sclerosis that antibodies to MIP-1␣ prevented the development of both initial and relapsing paralytic disease as well as infiltration of mononuclear cells into the central nervous system. Treatment wit...

Using a chemokine receptor model based on known receptor sequences, we identified several members of the seven transmembrane domain G-protein superfamily as potential chemokine receptors. The orphan receptor ChemR1, which has recently been shown to be a receptor for the CC chemokine I-309, scored very high in our model. We have confirmed that I-309, but not a number of other chemokines, can induce a transient Ca 2؉ flux in cells expressing CCR8. In addition, the human erythroleukemic cell line K562 responded chemotactically in a dose-responsive manner to this chemokine. Since several chemokine receptors have been shown to be required as coreceptors for HIV-1 infection, we asked whether human immunodeficiency virus type 1 (HIV-1) could efficiently utilize CCR8. Here we show that the CCR8 receptor can serve as a coreceptor for diverse T-cell tropic, dual-tropic, and macrophage-tropic HIV-1 strains and that I-309 was a potent inhibitor of HIV-1 envelope-mediated cell-cell fusion and virus infection. Furthermore, we show by flow cytometry and immunohistochemistry that antibodies generated against the CCR8 receptor amino-terminal peptide cross-reacted with U-87 MG cells stably expressing CCR8, THP-1 cells, HL-60 cells, and human monocytes, a target cell for HIV-1 infectivity in vivo.The chemokines are a diverse group of proteins that play an important role in host defense (1). They are classified into two major groups, CC and CXC, based on the position of the first two of their four invariant cysteines (2). Given their role in host defense, it is no surprise that chemokines and their receptors have been subjected to intense attack by pathogenic organisms. Some viruses have been shown to express viral chemokines and/or chemokine receptors (3-6) presumably as decoy proteins to help subvert the host immune response. Recently, human immunodeficiency virus type-1 (HIV-1) 1 has been shown to utilize chemokine receptors as coreceptors to infect cells. These findings provide new opportunities not only to study HIV-1 pathogenesis but also to develop new anti-viral strategies.While most HIV-1 strains use CD4 as a primary receptor, a specific chemokine receptor is also required for the membrane fusion reaction subsequent to virus infection. Generally, macrophage-tropic HIV-1 strains utilize CCR5 in conjunction with CD4 (7-11), while the T-cell tropic strains that typically emerge late in the course of the disease utilize CXCR4 (12, 13). In addition, dual-tropic viruses can efficiently utilize both of these receptors (8,9,14). Several other chemokine receptors have also been shown to function as coreceptors for a subset of HIV-1 strains, including CCR3 and CCR2b (8,9). The importance of chemokine receptors for HIV-1 pathogenesis in vivo is shown by the finding that approximately 1% of Caucasians are homozygous for a 32-base pair deletion in CCR5 that prevents its transport to the cell surface. These individuals are very highly resistant to virus infection (15)(16)(17)(18)(19).Given the importance of chemokines and their receptor...

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Incidence of antibody formation and positive direct antiglobulin tests in a muiltitransfuscd hemodialysis population.

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