Survival of Human T and B Lymphocytes after X-irradiation

Abstract

The survival of unstimulated human T [thymus derived] and B [bone marrow derived] lymphocytes after X-irradiation in vitro was measured by trypan blue dye exclusion for 4 days. B cell numbers declined, rapidly even after relatively low doses, but T cell numbers fell much more slowly. A comparison of the percentage survival 96 h after irradiation showed that in this system T cells .apprx. 2-5 times more resistant than B cells. Data for interphase death after 48 h are compared with cytogenetic data for interphase loss of PHA[phytohemagglutinin]-stimulated human lymphocytes and are in broad agreement at radiation doses < 400 rad. At higher doses mitotic delay may be increasingly important leading to selection of non-irradiated cells at 48 h.