Merck Millipore ChemiScreen Membrane Preparation Recombinant Rehsus CCR5

CCR5 is the receptor for CC chemokines MIP-1α, MIP-1β, and RANTES (Raport et al., 1996), and is preferentially expressed on Th1 lymphocytes (Loetscher et al., 1998). CCR5 is a coreceptor for macrophage-tropic HIV, and its ligands potently inhibit HIV replication in human leukocytes (Cocchi et al., 1995). In addition, HIV-infected patients with the nonfunctional CCR5Δ32 allele exhibit delayed onset of AIDS symptoms (Samson et al., 1996), and pharmacological antagonism of CCR5 inhibits HIV-1 infection (Strizki et al., 2001). Preclinical testing of small molecule antagonists of CCR5 has been hampered by low affinity of the compounds to rodent and dog CCR5, but two such compounds, maraviroc and AD101, have been shown to have potent antagonist activity at rhesus macaque CCR5, which differs from human CCR5 by 8 amino acids (Napier et al., 2005; Billick et al., 2004). One antagonist of human CCR5, SCH-C, does not block HIV entry through rhesus macaque CCR5, and one amino acid difference is responsible for the functional difference (Billick et al., 2004). Millipore's rhesus macaque CCR5 membrane preparations are crude membrane preparations made from our proprietary stable recombinant cell lines to ensure high-level of GPCR surface expression; thus, they are ideal HTS tools for screening of agonists and antagonists of rCCR5. The membrane preparations exhibit a Kd of 0.32 nM for [125I]-MIP-1α. With 0.25 nM [125I]-MIP-1α, 5 μg/well rCCR5 Membrane Prep typically yields greater than 7-fold signal-to-background ratio.