Monocyte chemotactic protein-1 inhibits the induction of nitric oxide synthase in J774 cells.

We evaluated the effect of monocyte chemotactic protein-1 (MCP-1) on the induction of nitric oxide synthase activity in J774 cells. MCP-1 was able to inhibit the production of nitric oxide induced by LPS and IFN-gamma in a dose-dependent manner. Moreover, the inhibition was only achieved when the cells were pretreated with MCP-1. No inhibition was observed when MCP-1 was added after stimulation with LPS and IFN-gamma. These results demonstrate that MCP-1 is able to inhibit the induction of nitric oxide synthesis.