SISTER-CHROMATID EXCHANGE IN HUMAN LYMPHOCYTES-B AND LYMPHOCYTES-T EXPOSED TO BLEOMYCIN, CYCLOPHOSPHAMIDE, AND ETHYL METHANESULFONATE

Sister-chromatid exchange (SCE) frequencies were investigated in mitogen-stimulated cultures of highly purified human peripheral blood B- and T-lymphocytes exposed to bleomycin (BM), cyclophosphamide (CP), or ethyl methanesulfonate (EMS). In untreated controls, T-lymphocytes showed twice as many SCEs as B-lymphocytes. CP (with metabolic activation) and EMS significantly increased the SCE frequencies. EMS induced a similar, dose-dependent SCE increase in both cell populations, whereas CP induced more SCEs in T- than in B-lymphocytes treated with BM.