Figure 2.

SCH-C is a CCR5 antagonist. (A) SCH-C antagonizes the calcium response to RANTES but does not itself induce a calcium signal. SCH-C at the concentrations indicated was added to B-550 cells loaded with the calcium-sensitive dye FURA-2 before addition of RANTES (10 nM). (B) SCH-C inhibits agonist-induced [³⁵S]GTPγS binding to the CCR5 receptor. SCH-C at the concentrations indicated was added to membrane preparations from CHO cells expressing hCCR5 in the presence (●) or absence (○) of MIP-1β (10 nM), and the amount of membrane-bound [³⁵S]GTPγS was determined. (C) SCH-C inhibits chemotaxis induced by MIP-1β. SCH-C (▴) at the concentrations indicated, or the equivalent concentration of DMSO (■), was added to B550 cells in the presence of MIP-1β (0.01 nM), and the extent of cell migration was determined. Spontaneous migration in the absence of chemokine was also measured (●).