Effects of low-dose radiation on the immune system of mice after total-body irradiation

Radiat Res. 2010 Oct;174(4):480-9. doi: 10.1667/RR2160.1.


The effects of acute exposure to low- and high-dose radiation on the quantitative and functional parameters of the immune system were analyzed. C57BL/6 mice were irradiated with different doses of γ radiation (0.01, 0.05, 0.1, 0.5 and 2 Gy) and splenocytes were isolated at various times. Alterations in the distribution and surviving fraction of splenocyte subsets such as CD4(+) and CD8(+) T lymphocytes, regulatory T cells (Treg), natural killer (NK) cells, dendritic cells (DCs) and B lymphocytes were analyzed by flow cytometry. Apoptosis frequency was quantified by the TdT-mediated dUTP-biotin nick end labeling (TUNEL) method 4 h after irradiation. Cytokine expression was investigated by real-time reverse transcription-polymerase chain reaction (RT-PCR). Low doses decreased apoptosis in the splenocyte subpopulations studied most prominently in NK cells and DCs. Exposure to 2 Gy increased apoptosis in all splenocyte subpopulations; B cells were the most sensitive and NK cells and DCs the least sensitive. The lowest cell numbers were measured 3 days after irradiation, with minor changes by day 7. CD8(+) and B cells were rather resistant to low doses but were very sensitive to 2 Gy, while NK cells, DCs and Treg cells were much more resistant to high doses. Expression of the T-helper 1 (Th1)- and helper 2 (Th2)-type cytokines decreased after low doses and increased after high doses. Interleukin 6 (IL-6) reacted at early times and IL-10 at later times. IL-5 levels were consistently elevated. These data highlight the differences in the responses of different splenocyte subpopulations to low- and high-dose radiation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / radiation effects
  • Cell Communication / radiation effects
  • Cell Count
  • Cell Survival / radiation effects
  • Cytokines / genetics
  • Cytokines / metabolism
  • Dose-Response Relationship, Radiation
  • Female
  • Gene Expression Regulation / radiation effects
  • Immune System / cytology
  • Immune System / metabolism
  • Immune System / radiation effects*
  • Immunity, Cellular / radiation effects
  • Immunity, Humoral / radiation effects
  • Kinetics
  • Lymphocyte Subsets / cytology
  • Lymphocyte Subsets / metabolism
  • Lymphocyte Subsets / radiation effects
  • Mice
  • Mice, Inbred C57BL
  • Spleen / immunology
  • Spleen / radiation effects
  • Whole-Body Irradiation


  • Cytokines