Dynamics of apoptosis in γ-irradiated lymphocytes and the CD21+CD27+ B-cell subset as a potential biodosimetric marker

The dynamics of apoptosis progression has been studied in human peripheral blood mononuclear cells (PBMC) irradiated with selected doses (0.5, 1, 2, 4, 6, 8 and 10 Gy) of 60Co γ rays and subsequently cultivated for 16 h in vitro. A dose-dependent increase and decrease of shrunk and intact cells, respectively, has been observed in the range of 0.5-4 Gy while higher doses have not affected the relative numbers of intact and apoptotic cells. The relative number of early apoptotic cells did not change within the dose range studied. Immunophenotyping of intact and very early apoptotic cells have indicated that the remaining intact cells represent the most convenient population for radioresistance studies in vitro. The CD21+CD27+ subset of peripheral B-cells has thus been suggested as a putative biodosimetric marker in vitro.