Abstract
We characterized highly radioresistant thymocytes as a candidate of p53-/- thymocytes, because the enrichment of p53-/- thymocytes by a high dose of irradiation could be expected from the facts that p53+/- thymocytes are sensitive to radiation-induced apoptosis but p53-/- thymocytes highly resistant. At various times post irradiation (6Gy), p53 heterozygous B10 mice were treated with a high dose (30Gy) of irradiation to enrich p53-/- thymocytes and, 24 hours later, the remaining thymocytes assayed for surface marker and p53 genotype. In a significant fraction of the mice 7wks after 6Gy-irradiation, we observed an abnormal increase of relative cell number of CD4+CD8+ thymocytes remaining in the thymus of highly irradiated mice and such abnormal thymocytes could be detected even 5 weeks after the irradiation. The abnormal CD4+CD8+ thymocytes were shown by PCR analysis of sorted cells to contain cells with p53-/- genotype. The data suggest that p53-/- thymocytes may appear as prelymphoma cells within several weeks post irradiation in CD4+CD8+ thymocyte subpopulation of irradiated p53 heterozygous mice. [J Radiat Res 44:394-395 (2003)]
