title: Activation of mouse lymphocytes inhibits induction of rapid cell death by x-irradiation.
abstract: A distinctive property of the resting lymphocyte is its ability to die rapidly in interphase after x-irradiation. Suspensions of thymocytes and peripheral lymphocytes from BALB/c mice were irradiated with doses ranging from 10 to 10,000 rad (0.1 to 100 Grays), and their viability was measured by eosin dye exclusion at intervals through 3 days of culture. After an initial latent period of a few hours, viability declined exponentially in a dose-dependent fashion. Doses as low as 20 rad caused some lymphocytes to die rapidly. After 1000 rad, 90% of the cells became nonviable in 15 to 20 hr and 99% in 25 to 35 hr. Peripheral lymphocytes showed a somewhat earlier loss of viability than did thymocytes, and were killed especially rapidly by 10,000 rad. Enriched T cells and B cells were killed by irradiation at equal rates, and medullary thymocytes were killed at the same rate as the whole thymocyte population. In contrast with resting cells, T and B lymphocytes activated by mitogens were not subject to such rapid induction of cell death. Irradiation with 1000 rad reduced the viability of activated cells by only 50% at a time when less than 1% of nonstimulated lymphocytes remained alive. Similarly, cloned lines of antigen-specific helper and cytotoxic T cells showed only a delayed and slow loss of viability after receiving 1000 rad. The state of activation can therefore be a significant determinant of the immunologic consequences of irradiation.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D007165:Immunosuppression Therapy; D008198:Lymph Nodes / Q000166:cytology; D008213:Lymphocyte Activation / Q000528:radiation effects*; D008214:Lymphocytes / Q000276:immunology* / Q000528:radiation effects; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D013601:T-Lymphocytes / Q000276:immunology / Q000528:radiation effects; D013997:Time Factors