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Chronic tumor necrosis factor alters T cell responses by attenuating T cell receptor signaling.

Cope AP, Liblau RS, Yang XD, Congia M, Laudanna C, Schreiber RD, Probert L, Kollias G, McDevitt HO - J. Exp. Med. (1997)

Bottom Line: Using a model of chronic TNF exposure in vitro, we demonstrate that (a) chronic TNF effects are dose and time dependent, (b) TNF suppresses the responses of both Th1 and Th2 T helper subsets, (c) the suppressive effects of endogenous TNF produced in T cell cultures could be reversed with neutralizing monoclonal antibodies to TNF, and (d) prolonged TNF exposure attenuates T cell receptor signaling.These effects are more pronounced in chronic inflammatory disease.In addition, our data provide a mechanism through which prolonged TNF exposure suppresses disease in animal models of autoimmunity.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, Stanford University School of Medicine, California 94305, USA.

ABSTRACT
Repeated injections of adult mice with recombinant murine TNF prolong the survival of NZB/W F1 mice, and suppress type I insulin-dependent diabetes mellitus (IDDM) in non-obese diabetic (NOD) mice. To determine whether repeated TNF injections suppress T cell function in adult mice, we studied the responses of influenza hemagglutinin-specific T cells derived from T cell receptor (HNT-TCR) transgenic mice. Treatment of adult mice with murine TNF for 3 wk suppressed a broad range of T cell responses, including proliferation and cytokine production. Furthermore, T cell responses of HNT-TCR transgenic mice also expressing the human TNF-globin transgene were markedly reduced compared to HNT-TCR single transgenic littermates, indicating that sustained p55 TNF-R signaling is sufficient to suppress T cell function in vivo. Using a model of chronic TNF exposure in vitro, we demonstrate that (a) chronic TNF effects are dose and time dependent, (b) TNF suppresses the responses of both Th1 and Th2 T helper subsets, (c) the suppressive effects of endogenous TNF produced in T cell cultures could be reversed with neutralizing monoclonal antibodies to TNF, and (d) prolonged TNF exposure attenuates T cell receptor signaling. The finding that anti-TNF treatment in vivo enhances T cell proliferative responses and cytokine production provides evidence for a novel regulatory effect of TNF on T cells in healthy laboratory mice. These effects are more pronounced in chronic inflammatory disease. In addition, our data provide a mechanism through which prolonged TNF exposure suppresses disease in animal models of autoimmunity.

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The effects of chronic TNF exposure on intracellular Ca2+  mobilization. BALB/c HNT-TCR transgenic T cells were stimulated in  vitro with HA 126-138 peptide in the presence or absence of repeated additions of 10 ng/ml TNF (a), or 10 μg/ml anti-TNF or control Ig (b).  Calcium fluxing was determined after 11 d in culture by spectrofluorometric (a), or by flow cytometric analyses (b), after restimulation of T cells  with fresh splenic APC loaded with 10 μg/ml peptide. Data are shown  for T cell/splenic APC cells in the presence or absence of 10 μg/ml HA  peptide, and expressed as \xc6  Ca2+ flux (335/380 nm) ratio (a: medium,  solid line, TNF, dotted line) as a function of time (min), or the % indo-1–positive, FITC-negative cells (b) fluxing during the first 60 s of analysis after  peptide stimulation.
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Figure 8: The effects of chronic TNF exposure on intracellular Ca2+ mobilization. BALB/c HNT-TCR transgenic T cells were stimulated in vitro with HA 126-138 peptide in the presence or absence of repeated additions of 10 ng/ml TNF (a), or 10 μg/ml anti-TNF or control Ig (b). Calcium fluxing was determined after 11 d in culture by spectrofluorometric (a), or by flow cytometric analyses (b), after restimulation of T cells with fresh splenic APC loaded with 10 μg/ml peptide. Data are shown for T cell/splenic APC cells in the presence or absence of 10 μg/ml HA peptide, and expressed as \xc6 Ca2+ flux (335/380 nm) ratio (a: medium, solid line, TNF, dotted line) as a function of time (min), or the % indo-1–positive, FITC-negative cells (b) fluxing during the first 60 s of analysis after peptide stimulation.

Mentions: The data described above demonstrated that prolonged TNF exposure suppresses a broad range of T cell responses after stimulation with antigenic peptide. These experiments compared T cell responses 24 h or more after peptide stimulation. To address the mechanism for chronic TNF effects, we wished to investigate whether chronic TNF modulates earlier events of the TCR signaling cascade. Accordingly, we evaluated the effects of prolonged TNF or anti-TNF exposure on mobilization of intracellular Ca2+ stores in transgenic T cells after restimulation with HA peptide. In preliminary experiments, transgenic T cells were stimulated with splenic APC loaded with 60 μg/ml HA peptide. No significant differences in Ca2+ fluxing was observed in T cells after chronic TNF treatment. However, when lower concentrations of peptide were used (10 μg/ml), different responses were observed. Fig. 8 shows representative data from Ca2+ fluxing experiments of BALB/c transgenic T cells determined by spectrofluorometric analysis (Fig. 8 a), and by flow cytometry (Fig. 8 b). In Fig. 8 a, spectrofluorometric analysis revealed that both the kinetics and amplitude of peptide specific Ca2+ mobilization in activated BALB/c transgenic T cells is altered by chronic TNF treatment; peak \xc6 Ca2+ ratios of 0.432 were observed after 43.89 s of analysis for control cultures, compared to a response of 0.228 at 58.52 s for TNF-treated cells. Experiments performed with B10.D2 cells revealed similar results; control versus TNF, a ratio of 0.137 after 54.34 s versus 0.075 after 87.78 s. These differences represented reductions in amplitude of >60% for BALB/c and ∼50% for B10.D2, as a consequence of chronic TNF exposure. Despite these differences, TNF-treated cells were still capable of sustaining Ca2+ mobilization throughout the test period.


Chronic tumor necrosis factor alters T cell responses by attenuating T cell receptor signaling.

Cope AP, Liblau RS, Yang XD, Congia M, Laudanna C, Schreiber RD, Probert L, Kollias G, McDevitt HO - J. Exp. Med. (1997)

The effects of chronic TNF exposure on intracellular Ca2+  mobilization. BALB/c HNT-TCR transgenic T cells were stimulated in  vitro with HA 126-138 peptide in the presence or absence of repeated additions of 10 ng/ml TNF (a), or 10 μg/ml anti-TNF or control Ig (b).  Calcium fluxing was determined after 11 d in culture by spectrofluorometric (a), or by flow cytometric analyses (b), after restimulation of T cells  with fresh splenic APC loaded with 10 μg/ml peptide. Data are shown  for T cell/splenic APC cells in the presence or absence of 10 μg/ml HA  peptide, and expressed as \xc6  Ca2+ flux (335/380 nm) ratio (a: medium,  solid line, TNF, dotted line) as a function of time (min), or the % indo-1–positive, FITC-negative cells (b) fluxing during the first 60 s of analysis after  peptide stimulation.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2196294&req=5

Figure 8: The effects of chronic TNF exposure on intracellular Ca2+ mobilization. BALB/c HNT-TCR transgenic T cells were stimulated in vitro with HA 126-138 peptide in the presence or absence of repeated additions of 10 ng/ml TNF (a), or 10 μg/ml anti-TNF or control Ig (b). Calcium fluxing was determined after 11 d in culture by spectrofluorometric (a), or by flow cytometric analyses (b), after restimulation of T cells with fresh splenic APC loaded with 10 μg/ml peptide. Data are shown for T cell/splenic APC cells in the presence or absence of 10 μg/ml HA peptide, and expressed as \xc6 Ca2+ flux (335/380 nm) ratio (a: medium, solid line, TNF, dotted line) as a function of time (min), or the % indo-1–positive, FITC-negative cells (b) fluxing during the first 60 s of analysis after peptide stimulation.
Mentions: The data described above demonstrated that prolonged TNF exposure suppresses a broad range of T cell responses after stimulation with antigenic peptide. These experiments compared T cell responses 24 h or more after peptide stimulation. To address the mechanism for chronic TNF effects, we wished to investigate whether chronic TNF modulates earlier events of the TCR signaling cascade. Accordingly, we evaluated the effects of prolonged TNF or anti-TNF exposure on mobilization of intracellular Ca2+ stores in transgenic T cells after restimulation with HA peptide. In preliminary experiments, transgenic T cells were stimulated with splenic APC loaded with 60 μg/ml HA peptide. No significant differences in Ca2+ fluxing was observed in T cells after chronic TNF treatment. However, when lower concentrations of peptide were used (10 μg/ml), different responses were observed. Fig. 8 shows representative data from Ca2+ fluxing experiments of BALB/c transgenic T cells determined by spectrofluorometric analysis (Fig. 8 a), and by flow cytometry (Fig. 8 b). In Fig. 8 a, spectrofluorometric analysis revealed that both the kinetics and amplitude of peptide specific Ca2+ mobilization in activated BALB/c transgenic T cells is altered by chronic TNF treatment; peak \xc6 Ca2+ ratios of 0.432 were observed after 43.89 s of analysis for control cultures, compared to a response of 0.228 at 58.52 s for TNF-treated cells. Experiments performed with B10.D2 cells revealed similar results; control versus TNF, a ratio of 0.137 after 54.34 s versus 0.075 after 87.78 s. These differences represented reductions in amplitude of >60% for BALB/c and ∼50% for B10.D2, as a consequence of chronic TNF exposure. Despite these differences, TNF-treated cells were still capable of sustaining Ca2+ mobilization throughout the test period.

Bottom Line: Using a model of chronic TNF exposure in vitro, we demonstrate that (a) chronic TNF effects are dose and time dependent, (b) TNF suppresses the responses of both Th1 and Th2 T helper subsets, (c) the suppressive effects of endogenous TNF produced in T cell cultures could be reversed with neutralizing monoclonal antibodies to TNF, and (d) prolonged TNF exposure attenuates T cell receptor signaling.These effects are more pronounced in chronic inflammatory disease.In addition, our data provide a mechanism through which prolonged TNF exposure suppresses disease in animal models of autoimmunity.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, Stanford University School of Medicine, California 94305, USA.

ABSTRACT
Repeated injections of adult mice with recombinant murine TNF prolong the survival of NZB/W F1 mice, and suppress type I insulin-dependent diabetes mellitus (IDDM) in non-obese diabetic (NOD) mice. To determine whether repeated TNF injections suppress T cell function in adult mice, we studied the responses of influenza hemagglutinin-specific T cells derived from T cell receptor (HNT-TCR) transgenic mice. Treatment of adult mice with murine TNF for 3 wk suppressed a broad range of T cell responses, including proliferation and cytokine production. Furthermore, T cell responses of HNT-TCR transgenic mice also expressing the human TNF-globin transgene were markedly reduced compared to HNT-TCR single transgenic littermates, indicating that sustained p55 TNF-R signaling is sufficient to suppress T cell function in vivo. Using a model of chronic TNF exposure in vitro, we demonstrate that (a) chronic TNF effects are dose and time dependent, (b) TNF suppresses the responses of both Th1 and Th2 T helper subsets, (c) the suppressive effects of endogenous TNF produced in T cell cultures could be reversed with neutralizing monoclonal antibodies to TNF, and (d) prolonged TNF exposure attenuates T cell receptor signaling. The finding that anti-TNF treatment in vivo enhances T cell proliferative responses and cytokine production provides evidence for a novel regulatory effect of TNF on T cells in healthy laboratory mice. These effects are more pronounced in chronic inflammatory disease. In addition, our data provide a mechanism through which prolonged TNF exposure suppresses disease in animal models of autoimmunity.

Show MeSH
Related in: MedlinePlus