Binding of Ovine Uterine Serpin to Lymphocytes

Authors

  • Wen-Jun Liu,

    1. Department of Dairy and Poultry Sciences, University of Florida, Gainesville, Florida
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    • Current address: Howard Hughes Medical Institute, Program in Molecular and Cell Biology. Oklahoma Medical Research Foundation, Oklahoma City

  • M.R. Peltier,

    1. Department of Dairy and Poultry Sciences, University of Florida, Gainesville, Florida
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  • P.J. Hansen

    Corresponding author
    1. Department of Dairy and Poultry Sciences, University of Florida, Gainesville, Florida
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P.O. Box 110920, University of Florida, Gainesville, FL 32611–0290

Abstract

PROBLEM: The endometrium of the sheep produces a progesterone-induced member of the serpin superfamily of serine proteinase inhibitors that can inhibit lymphocyte proliferation and reduce natural killer cell activity. Present results indicate that this molecule, called ovine uterine serpin (OvUS), can bind specifically to lymphocytes.

METHOD OF STUDY/RESULTS: Biotinylated OvUS bound to peripheral blood lymphocytes in a dose-dependent and saturable manner. Binding was inhibited by OvUS, but not by several other proteins, including serpin-enzyme complex (α1-antitrypsin-trypsin). Heparin blocked binding when added to the binding reaction or when used to pretreat lymphocytes. Both lymphocytes and Madin-Darby bovine kidney (MDBK) cells also bound fluorescein isothiocyanate-labeled OvUS.

CONCLUSIONS: Results suggest that OvUS can interact with lymphocytes and other cells through binding to a cell surface molecule. Such binding may indicate that inhibition of lymphocyte activation by OvUS involves 1) binding of OvUS to a cell surface receptor or 2) competitive inhibition of binding between OvUS and a co-activation molecule required for lymphocyte activation.

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