Chromosome instability induced in the cell progeny of human T lymphocytes irradiated in G(0) with gamma-rays

We report the occurrence of chromosome instability in human T lymphocytes i rradiated in vitro with gamma -rays and cultured for several generations be fore analysis. The delayed effects of gamma -radiation have been evaluated by conventional and molecular (chromosome painting) cytogenetics in prepara tions obtained from long-term bulk cultures or clonal cultures. The results indicate that the cell progeny of gamma irradiated human T lymphocytes can be characterized by a higher rate of chromosome damage, but this effect de pends on the individual donor response to ionizing radiation. Evidence has been collected about a differential involvement of chromosomes 7, 9 and 19 in the induced chromosome rearrangements, and this effect is equally visibl e as an immediate or delayed response of human T lymphocytes to ionizing ra diation.