Objective:To identify the differentially expressed proteins after activation of CCR5 by its ligand using two-dimensional electrophoresis.Methods: The HEK-293 cells stably expressing CCR5 were constructed.The global protein analysis in 293-CCR5 stables and mock cells was performed after treatment with RANTES.After analysis with the PDQuest image software,the differential spots were identified by MOLDI-TOF MS/MS.RT-PCR was performed to further analyze the changes at mRNA level.Results: Flow cytometry revealed that HEK-293 cells stably expressed CCR5.In this study,we analyzed the proteomic results to reveal the proteins which were significantly modulated by the activation of CCR5 with RANTES.Expression of dihydrofolate reductase was found in HEK-293 cells after RANTES treatment,which was confirmed by RT-PCR at the mRNA level.Conclusion: This proteomic study suggests that CCR5 activated by its ligand RANTES inhibits the expression of dihydrofolate reductase.