Quantification of thioguanine-resistant lymphocytes from mice irradiated in vivo.
Adult mice were Co-60 gamma irradiated, and 7 months later splenocytes were isolated, cultured in microwells, and the frequency of hprt-deficient mutants was determined by measuring the cloning efficiency in media with 6-thioguanine. The mutant frequency at 2, 4, and 6 Gy was 1.6 x 10(-5), 4.4 x 10(-5), and 12.7 x 10(-5), respectively. The frequency of spontaneous mutants was 2.5 x 10(-6). The effect of metabolic cooperation on the cloning efficiency of thioguanine-resistant T-cells in selective medium was evaluated in co-cultures with wild-type T-cells. We found that the growth of hprt-deficient T-cells is supported in the presence of thioguanine-inactivated wild-type splenocytes up to a cell density of 5 x 10(5) cells per well. When cell density was higher, cell growth was inhibited. Possibilities and limitations of cloned lymphocytes for the analysis of somatic mutations that occur in vivo are discussed.
Lorenz
R
R
Institute of Medical Radiation Research, University of Würzburg, Federal Republic of Germany.
Göllner
T
T
Hempel
K
K
D000818:Animals; D002999:Clone Cells; D004351:Drug Resistance; D005720:Gamma Rays; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D007958:Leukocyte Count; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects* / Q000528:radiation effects; D051379:Mice; D009152:Mutagenicity Tests / Q000379:methods*; D009154:Mutation; D013866:Thioguanine / Q000494:pharmacology*
D007041:Hypoxanthine Phosphoribosyltransferase; D013866:Thioguanine