Chronic effects of single and fractionated y-irradiation on an impairment of XXXX -related immune response.

@entity17843 @entity19 @entity61 @entity26102 @entity58 @entity630
PURPOSE: We already reported that levels of interferon (IFN)-y have been shown to be markedly reduced in @entity19 seven weeks after irradiation, resulting in a T helper (Th) 1/ @entity61 imbalance. To investigate whether the single or fractionated y-irradiation induced an immune imbalance, we analysed the @entity630 -related immune response profile until six months after the fractionated whole-body irradiation. METHODS AND MATERIALS: @entity19 were exposed to y-rays at a fractionated 5   Gy cumulative dose for five weeks. At two, four and six months later from the first exposure, experiments were performed. Cell populations in the spleen, the production of IFN-y, @entity58 and IL-12p70, natural killer (NK) cell activity and the expression of IL-12 receptors, @entity17843 and @entity26102 were detected. RESULTS: The IFN-y was lower in the @entity19 exposed by all irradiation conditions than in normal control @entity19 , but the @entity58 had increased in all the irradiated @entity19 . To investigate @entity630 profile, NK cell activity, IL-12p70 level and its receptor expression was confirmed. In all fractionated irradiation groups, the NK cell activity as well as the absolute numbers of NK cells was much decreased. Also, all the irradiated @entity19 showed a lower IL-12p70 level. However, the expression of IL-12 receptor b2 was lower in the irradiated @entity19 except the 0.2   Gy 10 @entity19 group. The phosphoylated @entity17843 was lower in all the irradiated @entity19 . This suppression was associated with an overexpression of @entity26102 . CONCLUSIONS: The fractionated whole-body irradiations of a dose of 5   Gy appear to be the down-regulation of the @entity630 -like immune response. These changes, in turn, maintain an immunological imbalance that persists in the long term.
