Abstract
The OX40 (CD134) molecule is induced primarily during T cell activation and, as we show in this study, is also expressed on CD25+CD4+ regulatory T (Treg) cells. A necessary role for OX40 in the development and homeostasis of Treg cells can be inferred from the reduced numbers of the cells present in the spleens of OX40-deficient mice, and their elevated numbers in the spleens of mice that overexpress the OX40 ligand (OX40L). The homeostatic proliferation of Treg cells following transfer into lymphopenic mice was also found to be potentiated by the OX40-OX40L interaction. Suppression of T cell responses by Treg cells was significantly impaired in the absence of OX40, indicating that, in addition to its homeostatic functions, OX40 contributes to efficient Treg-mediated suppression. However, despite this, we found that CD25-CD4+ T cells became insensitive to Treg-mediated suppression when they were exposed to OX40L-expressing cells, or when they were treated with an agonistic OX40-specific mAb. OX40 signaling could also abrogate the disease-preventing activity of Treg cells in an experimental model of inflammatory bowel disease. Thus, although the data reveal important roles for OX40 signaling in Treg cell development, homeostasis, and suppressive activity, they also show that OX40 signals can oppose Treg-mediated suppression when they are delivered directly to Ag-engaged naive T cells.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Animals
-
CD28 Antigens / physiology
-
CD4-Positive T-Lymphocytes / immunology
-
CD4-Positive T-Lymphocytes / metabolism
-
Cell Communication / genetics
-
Cell Communication / immunology*
-
Cell Differentiation / genetics
-
Cell Differentiation / immunology
-
Cell Division / genetics
-
Cell Division / immunology
-
Clonal Anergy / genetics
-
Clonal Anergy / immunology
-
Homeostasis / genetics
-
Homeostasis / immunology
-
Inflammatory Bowel Diseases / genetics
-
Inflammatory Bowel Diseases / immunology
-
Interleukin-2 / physiology
-
Ligands
-
Membrane Glycoproteins / deficiency
-
Membrane Glycoproteins / genetics
-
Membrane Glycoproteins / metabolism
-
Membrane Glycoproteins / physiology*
-
Mice
-
Mice, Inbred C57BL
-
Mice, Knockout
-
Mice, Transgenic
-
OX40 Ligand
-
Receptors, Interleukin-2 / biosynthesis
-
Receptors, Interleukin-2 / deficiency
-
Receptors, OX40
-
Receptors, Tumor Necrosis Factor / biosynthesis
-
Receptors, Tumor Necrosis Factor / deficiency
-
Receptors, Tumor Necrosis Factor / metabolism
-
Receptors, Tumor Necrosis Factor / physiology*
-
Signal Transduction / genetics
-
Signal Transduction / immunology
-
T-Lymphocyte Subsets / cytology
-
T-Lymphocyte Subsets / immunology*
-
T-Lymphocyte Subsets / metabolism*
-
T-Lymphocytes, Regulatory / immunology
-
Tumor Necrosis Factors
Substances
-
CD28 Antigens
-
Interleukin-2
-
Ligands
-
Membrane Glycoproteins
-
OX40 Ligand
-
Receptors, Interleukin-2
-
Receptors, OX40
-
Receptors, Tumor Necrosis Factor
-
Tnfrsf4 protein, mouse
-
Tnfsf4 protein, mouse
-
Tumor Necrosis Factors