Modifying Effect In Vivo of Interferon α 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 cells from the peripheral blood, spleen and thymus of mice treated with natural mouse interferon α (IFN-α) 24 and 48 h prior to γ irradiation were studied using the comet assay and apurinic-apyrimidinic (AP) site radiolabeling. It was demonstrated that the radiation-induced damage assessed by the comet assay in the DNA of peripheral blood lymphocytes (PBLs), splenocytes and thymocytes of mice treated with IFN-α 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 decrease 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-α activates the DNA repair systems in the cells of lymphoid tissue.