Biological dosimetry: the potential use of radiation-induced apoptosis in human T-lymphocytes.
An assay for biological dosimetry based on the induction of apoptosis in human T-lymphocytes is described. Radiation-induced apoptosis was assessed by flow cytometric identification of cells displaying apoptosis-associated DNA condensation. CD4 and CD8 T-lymphocytes were analysed. They were recognized on the basis of their cell-surface antigens. Four parameters were measured for both cell types: cell size, granularity, antigen immunofluorescence and DNA content. Apoptosis was quantified as the fraction of CD4-, or CD8-positive cells with a characteristic reduction of cell size and DNA content. At doses below 1 Gy, levels of radiation-induced apoptosis increased for up to 5 days after irradiation. Optimal dose discrimination was observed 4 days after irradiation, at which time the dose-response curves were linear, with a slope of 8% +/- 0.5% per 0.1 Gy. In controlled, dose-response experiments the lowest dose level at which the radiation-induced apoptosis frequency was still significantly above control was 0.05 Gy. After 5 days post-irradiation incubation, intra- and interdonor variations were measured and found to be similar; thus, apoptotic levels depend more on the dose than on the donor. The results demonstrate the potential of this assay as a biological dosimeter.
Menz
R
R
Department of Life Sciences, Paul Scherrer Institute, Switzerland.
Andres
R
R
Larsson
B
B
Ozsahin
M
M
Trott
K
K
Crompton
N E
NE
D017209:Apoptosis / Q000528:radiation effects*; D015496:CD4-Positive T-Lymphocytes / Q000473:pathology / Q000528:radiation effects*; D018414:CD8-Positive T-Lymphocytes / Q000473:pathology / Q000528:radiation effects*; D006801:Humans; D011874:Radiometry; D015203:Reproducibility of Results