Individual Variation and Age Dependency in the Radiosensitivity of Peripheral Blood T-lymphocytes from Normal Donors

Nan Mei, Hajime Imada, Satoshi Nomoto, Naoki Kunugita, Toshiyuki Norimura

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To investigate individual variation and age dependency in normal cell radiosensitivity, we measured the in vitro radiosensitivity of cultured peripheral blood T-lymphocytes derived from 56 healthy male blood donors. Dose-survival tests using colony formation assay were done with exponential growing T-cells (day 3, PHA-stimulated cells). 6-Thioguanine (6-TG)-resistant mutation assays at the hypoxanthine phosphoribosyl transferase (HPRT) locus were done with G0 phase T-cells (day 0, unstimulated cells). The mean inactivation dose (MID) computed by integration of the fitted survival curves was 1.25 ± 0.23 Gy (mean ± SD). The X-ray dose required to kill 90% of the cells (D10) was 2.81 ± 0.51 Gy. The MID ranged from 0.82 to 1.86 Gy with a coefficient of variation (CV) of 18%. The induced mutation frequencies (MF) per 106 cells at 2 Gy of X-rays ranged from 9.10 to 54.80 with a mean ± SD value of 24.63 ± 12.51 and a CV of 51%. It appears that the radiosensitivity of cell killing and mutagenicity varies among individuals. Although the spontaneous MF at the HPRT locus increases with age, the induced MF after exposure to 2 or 4 Gy of X-rays was not associated with age. Moreover, there were no significant correlations between age and MID values or the other dose-survival parameters. The findings indicate there is significant inter-individual variation in cellular radiosensitivity, but that in human T-lymphocytes aging does not affect the cytotoxic and mutagenic effects of X-irradiation.

Original languageEnglish
Pages (from-to)235-245
Number of pages11
JournalJournal of radiation research
Issue number4
Publication statusPublished - Dec 1996
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Radiation
  • Radiology Nuclear Medicine and imaging
  • Health, Toxicology and Mutagenesis


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