[Effect of natural human leukocyte interferon on cell cycle kinetics, the frequency of sister chromatid exchanges and chromosome aberrations in fopurin-treated human lymphocytes].

Natural human leukocyte interferon (50 IU/ml), added to human lymphocytes for 24 hour incubation time, increased the background sister chromatid exchange (SCE) frequency and shortened the average generation time (AGT). Interferon pretreatment decreased the levels of the SCE induced by antineoplastic alkylating drug fopurin (2-dimethylamino-6-diethylene iminophosphamido-7-methylpurine; treatment conditions: the 20-24 hour incubation time, 25 and 50 microM), but no statistically significant changes were noticed in AGTs, in the number of aberrant metaphases, and in the total number of induced chromosome aberrations (CA). The increased number of the exchange-type CA induced by fopurin (50 microM) was observed in interferon pretreated cells. The results obtained indicate different formation mechanisms for SCE and CA, as well as different modification ways of SCE and CA formation by interferon.