TY - JOUR

T1 - Bi-phasic effect of interferon (IFN)-alpha: IFN-alpha up- and down-regulates interleukin-4 signaling in human T cells

AU - Eriksen, Karsten Wessel

AU - Sommer, Viveca Horst

AU - Woetmann, Anders

AU - Rasmussen, Anette Bødker

AU - Brender, Christine

AU - Svejgaard, Arne

AU - Skov, Søren

AU - Geisler, Carsten

AU - Ødum, Niels

N1 - Keywords: CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; DNA-Binding Proteins; Humans; Interferon Type I, Recombinant; Interleukin-4; Models, Immunological; STAT1 Transcription Factor; STAT2 Transcription Factor; STAT6 Transcription Factor; Signal Transduction; T-Lymphocytes; Trans-Activators

PY - 2003

Y1 - 2003

N2 - Interferon (IFN)-alpha/beta is produced by virally infected cells and is believed to play an important role in early phases of the innate immune response. In addition, IFN-alpha/beta inhibits interleukin (IL)-4 signaling in B cells and monocytes, suggesting that IFN-alpha/beta (like IFN-gamma) is a Th1 cytokine. Here, we study cross-talk between IFN-alpha and IL-4 in human T cells. As expected, stimulation with IFN-alpha for 12-24 h inhibits IL-4 signaling. Surprisingly, however, IFN-alpha has the opposite effect on IL-4 signaling at earlier time points (up to 6 h). Thus, IFN-alpha enhances IL-4-mediated STAT6 activation in both CD4+ and CD8+ human T cells. The effect is specific because (i) another interferon, IFN-gamma, does not enhance IL-4-mediated STAT6 activation, (ii) IFN-alpha-mediated STAT1 and STAT2 activation is not modulated by IL-4, and (iii) activation of Janus kinases is not enhanced or prolonged by simultaneous stimulation with IFN-alpha and IL-4. Moreover, co-stimulation results in a selective increased STAT6/STAT2 association and an association between IFNAR/IL-4R components, suggesting that the IFNAR provides an additional STAT6 docking site via STAT2, leading to a more efficient dimerization/activation of STAT6 only. The co-stimulatory effect on STAT6 activation correlates with a cooperative increase in nuclear translocation, DNA binding, transcriptional activity, and mRNA expression of STAT6 target genes (IL-4Ralpha and IL-15Ralpha). In conclusion, we provide evidence that IFN-alpha both up- and down-regulates IL-4-mediated STAT6 signaling and thereby regulates the sensitivity to IL-4 in human T lymphocytes. Thus, our findings suggest that IFN-alpha has a complex regulatory role in adaptive immunity, which is different from the "classical" Th1 profile of IFN-gamma.

AB - Interferon (IFN)-alpha/beta is produced by virally infected cells and is believed to play an important role in early phases of the innate immune response. In addition, IFN-alpha/beta inhibits interleukin (IL)-4 signaling in B cells and monocytes, suggesting that IFN-alpha/beta (like IFN-gamma) is a Th1 cytokine. Here, we study cross-talk between IFN-alpha and IL-4 in human T cells. As expected, stimulation with IFN-alpha for 12-24 h inhibits IL-4 signaling. Surprisingly, however, IFN-alpha has the opposite effect on IL-4 signaling at earlier time points (up to 6 h). Thus, IFN-alpha enhances IL-4-mediated STAT6 activation in both CD4+ and CD8+ human T cells. The effect is specific because (i) another interferon, IFN-gamma, does not enhance IL-4-mediated STAT6 activation, (ii) IFN-alpha-mediated STAT1 and STAT2 activation is not modulated by IL-4, and (iii) activation of Janus kinases is not enhanced or prolonged by simultaneous stimulation with IFN-alpha and IL-4. Moreover, co-stimulation results in a selective increased STAT6/STAT2 association and an association between IFNAR/IL-4R components, suggesting that the IFNAR provides an additional STAT6 docking site via STAT2, leading to a more efficient dimerization/activation of STAT6 only. The co-stimulatory effect on STAT6 activation correlates with a cooperative increase in nuclear translocation, DNA binding, transcriptional activity, and mRNA expression of STAT6 target genes (IL-4Ralpha and IL-15Ralpha). In conclusion, we provide evidence that IFN-alpha both up- and down-regulates IL-4-mediated STAT6 signaling and thereby regulates the sensitivity to IL-4 in human T lymphocytes. Thus, our findings suggest that IFN-alpha has a complex regulatory role in adaptive immunity, which is different from the "classical" Th1 profile of IFN-gamma.

U2 - 10.1074/jbc.M310472200

DO - 10.1074/jbc.M310472200

M3 - Journal article

C2 - 14559900

VL - 279

SP - 169

EP - 176

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 1

ER -