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Lymphotoxin and LIGHT signaling pathways and target genes

Authors

  • Kirsten Schneider,

    1. Division of Molecular Immunology, La Jolla Institute for Allergy and Immunology, San Diego, CA, USA.
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    • *

      These two authors contributed equally to this work.

  • Karen G. Potter,

    1. Division of Molecular Immunology, La Jolla Institute for Allergy and Immunology, San Diego, CA, USA.
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    • *

      These two authors contributed equally to this work.

  • Carl F. Ware

    Corresponding author
    1. Division of Molecular Immunology, La Jolla Institute for Allergy and Immunology, San Diego, CA, USA.
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† Carl F. Ware
Division of Molecular Immunology
La Jolla Institute for Allergy and Immunology
10355 Science Center Drive
San Diego, CA 92121
USA
Fax: +1 858 558 3595
E-mail: cware@liai.org

Abstract

Summary:  Lymphotoxins (LTα and LTβ), LIGHT [homologous to LT, inducible expression, competes with herpes simplex virus (HSV) glycoprotein D for HSV entry mediator (HVEM), a receptor expressed on T lymphocytes], tumor necrosis factor (TNF), and their specific receptors LTβR, HVEM, and TNF receptor 1 (TNFR1) and TNFR2, form the immediate family of the larger TNF superfamily. These cytokines establish a critical communication system required for the development of secondary lymphoid tissues; however, knowledge of the target genes activated by these signaling pathways is limited. Target genes regulated by the LTαβ-LTβR pathway include the tissue-organizing chemokines, CXCL13, CCL19, and CCL21, which establish cytokine circuits that regulate LT expression on lymphocytes, leading to organized lymphoid tissue. Infectious disease models have revealed that LTαβ pathways are also important for innate and adaptive immune responses involved in host defense. Here, regulation of interferon-β by LTβR and TNFR signaling may play a crucial role in certain viral infections. Regulation of autoimmune regulator in the thymus via LTβR implicates LT/LIGHT involvement in central tolerance. Dysregulated expression of LIGHT overrides peripheral tolerance leading to T-cell-driven autoimmune disease. Blockade of TNF/LT/LIGHT pathways as an intervention in controlling autoimmune diseases is attractive, but such therapy may have risks. Thus, identifying and understanding the target genes may offer an opportunity to fine-tune inhibitory interventions.

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