Chemokines constitute a large family of secreted proteins that function as chemoattractants and activators of leukocytes. Astrocytes, the major glial cell type in the central nervous system (CNS), are a source of chemokine production within diseased brain. As such, we have examined the production of chemokines by human astroglioma cell lines and primary human astrocytes treated with a variety of stimuli, including LPS, TNF-α, IFN-γ and IL-1β. In addition, IL-6 in conjunction with the soluble IL-6 receptor (sIL-6R), and hybrid IL-6 (H-IL-6), a highly active fusion protein of sIL-6R and IL-6, were tested for their ability to induce chemokine expression. The findings presented herein demonstrate that both human astroglioma cell lines and primary human astrocytes express the CXC chemokines IP-10 and IL-8 and the CC chemokines MCP-1 and RANTES in response to TNF-α and IL-1β. IFN-γ induced the expression of IP-10, but not of IL-8, MCP-1 or RANTES. Surprisingly, IL-6/sIL-6R and H-IL-6 had little or no effect on chemokine expression in these cells. The effect of TGF-β on chemokine expression in human astroglioma cell lines and astrocytes was also examined. TGF-β alone had little or no effect on RANTES, MCP-1 and IL-8 expression; however, TGF-β synergized with TNF-α to enhance MCP-1 expression in both astroglioma cells and primary astrocytes. An inhibitory effect of TGF-β on TNF-α and IL-1β induced RANTES and IL-8 expression was observed in human astroglioma cells. In contrast, TGF-β enhanced TNF-α and IL-1β induction of IL-8 production by human astrocytes. These findings document a complex pattern of chemokine regulation by the pleiotropic cytokine TGF-β with both enhancing and inhibitory effects.