• BMB Reports
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• v.37 no.4
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• pp.507-514
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• 2004

Gamma irradiation ($\gamma$-IR) is reported to have diverse effects on immune cell apoptosis, survival and differentiation. In the present study, the immunomodulatory effect of a low dose $\gamma$-IR (5~10 Gy) was investigated, focusing on the role of NF-${\kappa}B$ in the induction of the B cell differentiation molecule, CD23/FceRII. In the human B cell line Ramos, $\gamma$-IR not only induced CD23 expression, but also augmented the IL-4-induced surface CD23 levels. While $\gamma$-IR did not cause STAT6 activation in these cells, it did induce both DNA binding and the transcriptional activity of NF-${\kappa}B$ in the $I{\kappa}B$ degradation-dependent manner. It was subsequently found that different NF-${\kappa}B$ regulating signals modulated the $\gamma$-IR-or IL-4-induced CD23 expression. Inhibitors of NF-${\kappa}B$ activation, such as PDTC and MG132, suppressed the $\gamma$-IR-mediated CD23 expression. In contrast, Ras, which potentiates $\gamma$-IR-induced NF-${\kappa}B$ activity in these cells, further augmented the $\gamma$-IR- or IL-4-induced CD23 levels, The induction of NF-${\kappa}B$ activation and the subsequent up-regulation of CD23 expression by $\gamma$-IR were also observed in monocytic cells. These results suggest that $\gamma$-IR, at specific dosages, can modulate immune cell differentiation through the activation of NF-${\kappa}B$, and this potentially affects the immune inflammatory response that is mediated by cytokines.