Abstract
Programmed death-1 (PD-1) usually acts as a negative signal for T cell activation, and its expression on CD8(+)Foxp3(+) T cells is required for their suppressive capacity. In this study, we show that PD-1 signaling is required for the maintenance of functional regulatory CD4(+)CD25(+)Foxp3(+) regulatory T cells (CD4(+) T(reg)) that can control autoimmunity in (New Zealand Black × New Zealand White)F1 lupus mice. PD-1 signaling induced resistance to apoptosis and prolonged the survival of CD4(+) T(reg). In vivo, the blockade of PD-1 with a neutralizing Ab reduced PD-1 expression on CD4(+) T(reg) (PD1(lo)CD4(+) T(reg)). PD1(lo)CD4(+) T(reg) had an increased ability to promote B cell apoptosis and to suppress CD4(+) Th as compared with CD4(+) T(reg) with elevated PD-1 expression (PD1(hi)CD4(+) T(reg)). When PD-1 expression on CD4(+) T(reg) was blocked in vitro, PD1(lo)CD4(+) T(reg) suppressed B cell production of IgG and anti-dsDNA Ab. Finally, in vitro studies showed that the suppressive capacity of CD4(+) T(reg) depended on PD-1 expression and that a fine-tuning of the expression of this molecule directly affected cell survival and immune suppression. These results indicate that PD-1 expression has multiple effects on different immune cells that directly contribute to a modulation of autoimmune responses.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptive Immunity
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Animals
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Antibodies, Monoclonal / administration & dosage
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Antibodies, Monoclonal / pharmacology*
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Antibodies, Neutralizing / administration & dosage
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Antibodies, Neutralizing / pharmacology*
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Autoantibodies / biosynthesis
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CD4 Antigens / metabolism
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Disease Progression
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Female
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Gene Expression Regulation / drug effects
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Immune Tolerance / drug effects
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Immune Tolerance / genetics
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Interleukin-2 / genetics
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Interleukin-2 / immunology
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Interleukin-2 Receptor alpha Subunit / metabolism
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Interleukin-6 / immunology
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Interleukin-6 / metabolism
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Lupus Erythematosus, Systemic / immunology*
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Lupus Erythematosus, Systemic / prevention & control
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Mice
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Mice, Inbred NZB
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Programmed Cell Death 1 Receptor / antagonists & inhibitors*
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Programmed Cell Death 1 Receptor / metabolism
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Signal Transduction
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T-Lymphocytes, Regulatory / drug effects
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T-Lymphocytes, Regulatory / immunology*
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T-Lymphocytes, Regulatory / metabolism*
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Transforming Growth Factor beta / immunology
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Transforming Growth Factor beta / metabolism
Substances
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Antibodies, Monoclonal
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Antibodies, Neutralizing
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Autoantibodies
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CD4 Antigens
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Interleukin-2
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Interleukin-2 Receptor alpha Subunit
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Interleukin-6
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Programmed Cell Death 1 Receptor
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Transforming Growth Factor beta