Sister chromatid exchange in highly purified human B and T lymphocytes.

Sister chromatid exchange (SCE) rates were determined in human peripheral blood B and T lymphocyte populations highly purified by immunologic methods. The purified populations were supplemented with gamma-irradiated unseparated autologous mononuclear cells to restore helper-functions and stimulated with pokeweed mitogen (PWM) and phytohemagglutinin (PHA), respectively. Measured at the different peaks of proliferation after identical bromodeoxyuridine (BrdU) incubation times, T lymphocytes showed significantly higher SCE frequencies than B lymphocytes. In both populations, different proliferation kinetics and a different minimal BrdU concentration for sister chromatid differentiation (SCD) were observed.