We have investigated two assays for measuring the induction of mutations using human T-lymphocytes isolated from leukocyte residue buffy coats obtained from normal donors. Variant cell frequency of T-cells defective in the T-cell receptor (TCR) gene expression was measured using a 2-color flow cytometry, and 6-thioguanine-resistant (TG(r)) cells were determined using a cloning technique at the HPRT gene after treatment with 250 kVp X-rays or ethylnitrosourea (ENU). The frequencies of TCR mutant cells as well as those of TG(r) cells increased with increasing doses of X-rays or concentrations of ENU studied. For TCR mutants, the induced mutation frequencies at D37 (giving 37% survival) were 31.7 x 10-4 and 11.0 x 10-4 for X-rays and ENU, respectively. For TG(r) T-cell, the induced mutation frequencies at D37 for the same mutagens were 14.4 x 10-6 and 75.5 x 10-6, respectively. Over the dose range studied, the relationship appears to be linear between the mutation induction of TCR and that of TG(r) for X-rays or ENU. However, X-rays may induce more TCR mutants against less induction TG(r) T-cells, and ENU may cause a reverse result. The sensitivity of the assay of each biological endpoint in human blood T-lymphocytes may be different.
|Number of pages||7|
|Journal||Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis|
|Publication status||Published - Oct 25 1996|
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Health, Toxicology and Mutagenesis