MICRONUCLEI AND MITOTIC INDEX IN B-CELLS, T4-CELLS AND T8-CELLS TREATED WITH MITOMYCIN-C AND GAMMA-IRRADIATION

Lymphocytes were treated in vitro with mitomycin C and gamma-radiation at different doses (0-250 nmol/l and 0-2 Gy, respectively). After inc ubation in RPMI 1640 medium and stimulation with phytohemagglutinin fo r 72 h, the lymphocyte subgroups T4 (CD4), T8 (CD8) and B (CD19) were separated by an immunomagnetic method and analyzed for the presence of micronuclei. With mitomycin C the highest levels were found in T4- an d B-cells. When micronuclei were induced by irradiation the T4-cells s howed the highest frequencies and the B-cells the lowest. The outcome of B-cells with gamma-irradiation was probably due to a pronounced cyt otoxic reaction in this cell type, which could be measured as a decrea se in mitotic index.