RADIATION-INDUCED MICRONUCLEI IN SUBPOPULATIONS OF HUMAN-LYMPHOCYTES

The micronucleus expression in T-helper, T-suppressor and B lymphocytes of the peripheral blood was studied after in vitro exposure to high (2.5 Gy and 5 Gy) and low (0.5 Gy and 1 Gy) doses of ionizing radiation. Investigations were carried out by combining the micronucleus assay with immunofluorescence staining using subpopulation specific antibodies. While in the higher dose range B cell proliferation was inhibited nearly completely - so that micronuclei could not be expressed - we found after exposure to lower doses that B cells were the lymphocyte subpopulation which was most sensitive to micronucleus induction. Among the T cell population, the T-suppressor subset revealed a higher yield of micronuclei than T-helper cells, whereas with regard to the effect of radiation on proliferative ability, T-helper cells reacted more sensitively than the T-suppressor lymphocytes. Our studies provide insight into the effect of radiation exposure on the micronucleus expression of lymphocyte subpopulations and new information which may be useful for the further development of biological dosimetry.