Gamma Irradiation-reduced IFN-γ Expression, STAT1 Signals, and Cell-mediated Immunity
2002; Korean Society for Biochemistry and Molecular Biology; Volume: 35; Issue: 6 Linguagem: Inglês
10.5483/bmbrep.2002.35.6.583
ISSN1976-670X
AutoresSeon-Kyu Han, Jie‐Young Song, Yeon‐Sook Yun, Seh-Yoon Yi,
Tópico(s)NF-κB Signaling Pathways
ResumoThe signal transducer and activator of transcription (STAT)1 is a cytoplasmic-transcription factor that is phosphorylated by Janus kinases (Jak) in response to interferon $\gamma$ (IFN- $\gamma$ ). The phosphorylated STAT1 translocates to the nucleus, where it turns on specific sets of IFN- $\gamma$ -inducible genes, such as the interferon regulatory factor (IRF)-1. We show here that gamma irradiation reduces the IFN- $\gamma$ mRNA expression. The inhibition of the STAT1 phosphorylation and the IRF-1 expression by gamma irradiation was also observed. In contrast, the mRNA levels of IL-5 and transcription factor GATA-3 were slightly induced by gamma irradiation when compared to the non-irradiated sample. Furthermore, we detected the inhibition of cell-mediated immunity by gamma irradiation in the allogenic-mixed lymphocytes' reaction (MLR). These results postulate that gamma irradiation induces the polarized-Th2 response and interferes with STAT1 signals, thereby causing the immunosuppression of the Th1 response.
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