RANTES is a C-C (beta)-family chemokine that is implicated in the migration of peripheral blood leukocytes to brain lesions in multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system (CNS). Glial cells are active participants in the inflammatory response in the CNS, and they have been shown to respond to and produce a number of cytokines and chemokines in vivo and in vitro. Recently, we have shown inducibility of RANTES gene expression by TNF-alpha in human astrocytic cells. Therefore, the goal of the current study was to investigate the transcription activating factor involved in the process. We found that the induction of RANTES mRNA and protein by TNF-alpha in human astrocytic cells is associated with increased NF-kappaB DNA-binding activity. p65 and p50 were determined to be the components of the activated NF-kappaB transcription factor complex by supershift assay. In addition, the blockade of NF-kappaB activation by three known NF-kappaB inhibitors markedly reduced the TNF-alpha-induced RANTES expression at the mRNA and protein levels. Furthermore, the reduction in NF-kappaB binding activity to the promoter of the human RANTES gene caused by the NF-kappaB inhibitors parallels a decrease in RANTES expression in these cells. Our data suggest that NF-kappaB may mediate the induction of RANTES gene expression, in human glial cells, through its cognate cis-acting element.