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Blood, 1 January 2008, Vol. 111, No. 1, pp. 251-259. Prepublished online as a Blood First Edition Paper on October 1, 2007; DOI 10.1182/blood-2007-03-081646. This Article Full Text Full Text (PDF) Supplemental Figures All Versions of this Article: blood-2007-03-081646v1 111/1/251    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Zarek, P. E. Articles by Powell, J. D. Search for Related Content PubMed PubMed Citation Articles by Zarek, P. E. Articles by Powell, J. D. Related Collections Signal Transduction Immunobiology Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  IMMUNOBIOLOGY A2A receptor signaling promotes peripheral tolerance by inducing T-cell anergy and the generation of adaptive regulatory T cells Paul E. Zarek1, Ching-Tai Huang2, Eric R. Lutz3, Jeanne Kowalski4, Maureen R. Horton5, Joel Linden6, Charles G. Drake3, and Jonathan D. Powell1,3 1 Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD; 2 Department of Internal Medicine, Chang Gung Memorial Hospital, Taipei, Taiwan; 3 Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, 4 Department of Oncology Biostatistics, and 5 Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD; and 6 Department of Medicine, University of Virginia, Charlottesville, VA Tissue-derived adenosine, acting via the adenosine A2A receptor (A2AR), is emerging as an important negative regulator of T-cell function. In this report, we demonstrate that A2AR stimulation not only inhibits the generation of adaptive effector T cells but also promotes the induction of adaptive regulatory T cells. In vitro, antigen recognition in the setting of A2AR engagement induces T-cell anergy, even in the presence of costimulation. T cells initially stimulated in the presence of an A2AR agonist fail to proliferate and produce interleukin-2 and interferon (IFN)- when rechallenged in the absence of A2AR stimulation. Likewise, in an in vivo model of autoimmunity, tissue-derived adenosine promotes anergy and abrogates tissue destruction. Indeed, A2AR stimulation inhibits interleukin-6 expression while enhancing the production of transforming growth factor-β. Accordingly, treating mice with A2AR agonists not only inhibits Th1 and Th17 effector cell generation but also promotes the generation of Foxp3+ and LAG-3+ regulatory T cells. In this regard, A2AR agonists fail to prevent autoimmunity by LAG-3–/– clonotypic T cells, implicating an important role for LAG-3 in adenosine-mediated peripheral tolerance. Overall, our findings demonstrate that extracellular adenosine stimulates the A2AR to promote long-term T-cell anergy and the generation of adaptive regulatory T cells. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

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