IFN-β is widely used in the treatment of multiple sclerosis, yet the mechanism facilitating its efficacy remains unclear. IL-2 production by activated T cells, including those mediating autoimmunity, and subsequent autocrine stimulation is vital for T cell expansion and function. In this study, we demonstrate that in mouse and human T cells, IFN-β specifically inhibits the production of IL-2 upon TCR engagement without affecting other cytokines or activation markers. Rather than disrupting TCR signaling, IFN-β alters histone modifications in the IL-2 promoter to retain the locus in an inaccessible configuration. This in turn is mediated through the upregulation of the transcriptional suppressor CREM by IFN-β and consequent recruitment of histone deacetylases to the IL-2 promoter. In accordance, ablation of CREM expression or inhibition of histone deacetylases activity eliminates the suppressive effects of IFN-β on IL-2 production. Collectively, these findings provide a molecular basis by which IFN-β limits T cell responses.
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Copyright © 2015 by The American Association of Immunologists, Inc.