MODIFYING EFFECT IN-VIVO OF INTERFERON-ALPHA ON INDUCTION AND REPAIR OF LESIONS IN DNA OF LYMPHOID-CELLS OF GAMMA-IRRADIATED MICE

The induction of structural lesions and repair in DNA of lymphoid cell s from the peripheral blood, spleen and thymus of mice treated with na tural mouse interferon alpha (IFN-alpha) 24 and 48 h prior to gamma ir radiation were studied using the comet assay and apurinic-apyrimidinic (AP) site radiolabeling. It was demonstrated that the radiation-induc ed damage assessed by the comet assay in the DNA of peripheral blood l ymphocytes (PBLs), splenocytes and thymocytes of mice treated with IFN -alpha before irradiation was considerably less and was repaired more easily in the postirradiation period than that in untreated mice. The DNA of PBLs and splenocytes from interferon-treated mice showed a decr ease in the spontaneously occurring and radiation-induced AP sites, as determined immediately and 90 min after irradiation, compared to the level of AP sites in the DNA of untreated mice. The results lead us to assume that IFN-alpha activates the DNA repair systems in the cells o f lymphoid tissue. (C) 1996 by Radiation Research Society