Activation of C-C β-chemokines in human peripheral blood γδ T cells by isopentenyl pyrophosphate and regulation by cytokines

Abstract

Abstract Human γδ T lymphocytes respond to viral, bacterial, protozoal, and tumoral antigens, but their precise function remains unknown. In adults the major circulating γδ T-cell subset expresses the Vγ9Vδ2 T-cell receptor and responds to protease-resistant phosphorylated derivatives found in many pathogens. In this study we show that activation of Vδ2+ cells with the nonpeptidic antigen isopentenyl pyrophosphate (IPP) rapidly induces (within 4-12 hours) the C-C chemokines MIP-1, MIP-1β, and lymphotactin but not MCP-1. The most robust response was obtained for MIP-1β. IPP induction of MIP-1 and MIP-1β was not affected by costimulation with interleukin-4 (IL-4), IL-10, TGF-β, or interferon-γ (INF-γ). However, IL-12 significantly enhanced IPP-induced expression and release of MIP-1 that was down-regulated by TGF-β whereas the induction of MIP-1β by IPP+IL-12 was refractory to cotreatment with TGFβ indicating that these chemokines are differentially regulated by these cytokines. Vδ2+ T cells also expressed a wide range of C-C chemokine receptors including CCR1, CCR5, and CCR8, all of which were down-regulated following activation. We conclude that Vδ2+ cells can be rapidly induced by components of bacterial cell walls to express high levels of proinflammatory chemokines, supporting an important role for these cells in the early stages of the inflammatory responses to many common pathogens. (Blood. 2000, 95:39-47)