PURPOSE: To elaborate the B-cell micronucleus (MN) response in the low-dose region in detail and to investigate the postulated deficiency in DNA-PK in B-cells. MATERIALS AND METHODS: Lymphocytes of five healthy volunteers were irradiated with low LET gamma-rays and high LET fast neutrons with doses ranging between 0.01 and 2 Gy. After post-irradiation incubation, B- and T-cells were isolated via CD3 and CD19 immunomagnetic microbeads. MN were analysed in both subpopulations. To study the underlying mechanism of chromosomal radiosensitivity, cell extracts prepared from purified B- and T-cells were subjected to SDS-electrophoresis and electroblotting using antibodies directed against the DNA-PK repair enzymes Ku70/86 and DNA-PKcs. Activity measurements were performed using the SignaTECT DNA-dependent protein kinase assay. DNA double-strand break (DSB) induction and rejoining was determined using constant-field gel electrophoresis. RESULTS: For low LET gamma-rays a higher MN yield was observed in B-cells than in T-cells, but only in those samples exposed to doses < 1 Gy. For 1 Gy, the MN yields were comparable and for 2Gy even lower in B-cells compared with T-cells. After high LET neutron irradiation no significant differences in MN yields were observed between both subsets. The results of the DNA-PK experiments demonstrate that there is no difference between T- and B-cells in the basal expression and activity of DNA-PK repair proteins. No differences in DNA DSB induction and rejoining were found between T- and B-cells using constant-field gel electrophoresis. CONCLUSIONS: From the results, it was concluded that the enhanced chromosomal radiosensitivity in B-cells is restricted to low doses (<1 Gy) of low LET radiation and that the chromosomal behaviour of B-cells to low LET radiation cannot be attributed to aberrant forms of the DNA-PK components. A type of chromosomal induced radioresistance (IRR) may be a possible explanation for the observed effect.
PURPOSE: To elaborate the B-cell micronucleus (MN) response in the low-dose region in detail and to investigate the postulated deficiency in DNA-PK in B-cells. MATERIALS AND METHODS: Lymphocytes of five healthy volunteers were irradiated with low LET gamma-rays and high LET fast neutrons with doses ranging between 0.01 and 2 Gy. After post-irradiation incubation, B- and T-cells were isolated via CD3 and CD19 immunomagnetic microbeads. MN were analysed in both subpopulations. To study the underlying mechanism of chromosomal radiosensitivity, cell extracts prepared from purified B- and T-cells were subjected to SDS-electrophoresis and electroblotting using antibodies directed against the DNA-PK repair enzymes Ku70/86 and DNA-PKcs. Activity measurements were performed using the SignaTECT DNA-dependent protein kinase assay. DNA double-strand break (DSB) induction and rejoining was determined using constant-field gel electrophoresis. RESULTS: For low LET gamma-rays a higher MN yield was observed in B-cells than in T-cells, but only in those samples exposed to doses < 1 Gy. For 1 Gy, the MN yields were comparable and for 2Gy even lower in B-cells compared with T-cells. After high LET neutron irradiation no significant differences in MN yields were observed between both subsets. The results of the DNA-PK experiments demonstrate that there is no difference between T- and B-cells in the basal expression and activity of DNA-PK repair proteins. No differences in DNA DSB induction and rejoining were found between T- and B-cells using constant-field gel electrophoresis. CONCLUSIONS: From the results, it was concluded that the enhanced chromosomal radiosensitivity in B-cells is restricted to low doses (<1 Gy) of low LET radiation and that the chromosomal behaviour of B-cells to low LET radiation cannot be attributed to aberrant forms of the DNA-PK components. A type of chromosomal induced radioresistance (IRR) may be a possible explanation for the observed effect.
Authors: Katia Vandenbulcke; Filip De Vos; Fritz Offner; Jan Philippé; Christos Apostolidis; Roger Molinet; Tuomo K Nikula; Klaus Bacher; Virginie de Gelder; Anne Vral; Christophe Lahorte; Hubert Thierens; Rudi A Dierckx; Guido Slegers Journal: Eur J Nucl Med Mol Imaging Date: 2003-07-03 Impact factor: 9.236
Authors: Pierre Lebailly; Gladys Mirey; Fabrice Herin; Yannick Lecluse; Bernard Salles; Elisa Boutet-Robinet Journal: Int Arch Occup Environ Health Date: 2015-02-03 Impact factor: 3.015