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Mediators of Inflammation
Volume 2014, Article ID 485743, 10 pages
http://dx.doi.org/10.1155/2014/485743
Research Article

Consequences of the Lack of CD73 and Prostatic Acid Phosphatase in the Lymphoid Organs

1MediCity Research Laboratory, University of Turku, Tykistökatu 6 A, 20520 Turku, Finland
2Department of Medical Microbiology and Immunology, University of Turku, 20014 Turku, Finland
3National Institute for Health and Welfare, 20520 Turku, Finland
4Department of Physiology and Turku Center for Disease Modeling, Institute of Biomedicine, University of Turku, 20014 Turku, Finland
5Department of Medical Biochemistry and Genetics, University of Turku, 20014 Turku, Finland
6Department of Clinical Chemistry, and Helsinki University Hospital Laboratory, University of Helsinki, 00014 Helsinki, Finland

Received 2 May 2014; Revised 27 June 2014; Accepted 7 August 2014; Published 24 August 2014

Academic Editor: Jean Sévigny

Copyright © 2014 Gennady G. Yegutkin et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

CD73, ecto-5′-nucleotidase, is the key enzyme catalyzing the conversion of extracellular AMP to adenosine that controls vascular permeability and immunosuppression. Also prostatic acid phosphatase (PAP) possesses ecto-5′-nucleotidase/AMPase activity and is present in leukocytes. However, its role related to immune system is unknown. Therefore, we analyzed enzymatic activities and leukocyte subtypes of CD73 and PAP knockouts and generated CD73/PAP double knockout mice to elucidate the contribution of CD73 and PAP to immunological parameters. Enzymatic assays confirmed the ability of recombinant human PAP to hydrolyze [3H]AMP, although at much lower rate than human CD73. Nevertheless, 5′-nucleotidase/AMPase activity in splenocytes and lymphocytes from PAP−/− mice tended to be lower than in wild-type controls, suggesting potential contribution of PAP, along with CD73, into lymphoid AMP metabolism ex vivo. Single knockouts had decreased number of regulatory T cells in thymus and CD73/PAP double knockouts exhibited reduced percentages of CD4+ cells in spleen, regulatory T cells in lymph nodes and thymus, and CD4+ and CD8+ cells in blood. These findings suggest that PAP has a synergistic role together with CD73 in the immune system by contributing to the balance of leukocyte subpopulations and especially to the number of regulatory T cells in lymph nodes and thymus.