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BNS in T Cell Cytokine Regulation As Revealed by Targeted Gene Disruption1







* Laboratory of Immunobiology, Department of Medical Oncology, Dana Farber Cancer Institute, and
Department of Medicine, Harvard Medical School, Boston, MA 02115;
Baylor Institute for Immunology Research, Dallas, TX 75204; and
Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115
Triggering of the TCR by cognate peptide/MHC ligands induces expression of I
BNS, a member of the I
B family of NF-
B inhibitors whose expression is associated with apoptosis of immature thymocytes. To understand the role of I
BNS in TCR triggering, we created a targeted disruption of the I
BNS gene. Surprisingly, mice lacking I
BNS show normal thymic progression but both thymocytes and T cells manifest reduced TCR-stimulated proliferation. Moreover, I
BNS knockout thymocytes and T cells produce significantly less IL-2 and IFN-
than wild-type cells. Transfection analysis demonstrates that I
BNS and c-Rel individually increase IL-2 promoter activity. The effect of I
BNS on the IL-2 promoter, unlike c-Rel, is dependent on the NF-
B rather than the CD28RE site; mutation of the NF-
B site extinguishes the induction of transcription by I
BNS in transfectants and prevents association of I
BNS with IL-2 promoter DNA. Microarray analyses confirm the reduction in IL-2 production and some IFN-
-linked transcripts in I
BNS knockout T cells. Collectively, our findings demonstrate that I
BNS regulates production of IL-2 and other cytokines induced via "strong" TCR ligation.
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
1 This work was supported by National Institutes of Health Grants AI19807 (to E.L.R.) and AI51779 (to L.K.C.).
2 Current address: Beth Israel Deaconess Medical Center Genomic Center, Department of Medicine, Harvard Medical School, Boston, MA 02115.
3 Current address: Department of Molecular and Cell Biology, Division of Immunology and Cancer Research Laboratory, University of California, Berkeley, CA 94720.
4 Current address: Center for Vascular Biology, University of Connecticut Health Center, Farmington, CT 06030.
5 Address correspondence and reprint requests to Dr. Linda K. Clayton, Dana Farber Cancer Institute, 77 Avenue Louis Pasteur, Boston, MA 02115. E-mail address: linda_clayton{at}dfci.harvard.edu
6 Abbreviations used in this paper: pMHC, peptide-MHC complex; DP, double positive; DN, double negative; LN, lymph node; WT, wild type; KO, knockout; BM, bone marrow; FC, fold change; rh, recombinant human; SAP, SLAM-associated protein.
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