Stimulated rapid expression in vitro for early detection of in vivo T-cell receptor mutations induced by radiation exposure
| Autor: | Takashi Kodama, Mitoshi Akiyama, K. Ohama, Shigeko Umeki, Yuko Hirai, Nahoko Ishioka, Seishi Kyoizumi |
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| Rok vydání: | 1997 |
| Předmět: |
Antigens
Differentiation T-Lymphocyte CD4-Positive T-Lymphocytes Male Health Toxicology and Mutagenesis medicine.medical_treatment Mutant Receptors Antigen T-Cell Gene Expression Uterine Cervical Neoplasms Biology Lymphocyte Activation Ionizing radiation In vivo Genetics medicine Humans Phytohemagglutinins Receptor Cells Cultured T-cell receptor Cancer Dose-Response Relationship Radiation Radiotherapy Dosage Flow Cytometry medicine.disease Molecular biology In vitro Radiation therapy Mutagenesis Mutation Interleukin-2 Female Cell Division |
| Zdroj: | Mutation Research/Genetic Toxicology and Environmental Mutagenesis. 390:269-282 |
| ISSN: | 1383-5718 |
| Popis: | The T-cell receptor (TCR) mutation assay for in vivo somatic mutations is a sensitive indicator of exposure to ionizing radiation. However, this assay cannot be immediately applied after radiation exposure because expression of a mutant phenotype may require as long as several months. In the present study, we eliminate this time lag by stimulating lymphocytes with a mitogen that can accelerate the turnover of TCR protein expression in T-cells. When lymphocytes obtained from healthy donors were irradiated with various doses of X-rays and cultured with human interleukin-2 after phytohemagglutinin (PHA) pulse stimulation, the mutant frequency (MF) of CD4+ T-cells increased dose dependently during the first 7 days, then decreased rapidly due to the growth disadvantage of mutant cells. This suggests that PHA stimulation can shorten the expression time of a mutant phenotype to within a week after radiation exposure. The relationship between radiation dose and TCR MF on the seventh day was best fitted by a linear-quadratic dose–response model. We applied this improved TCR mutation assay to gynecological cancer patients who received 5 days of localized radiotherapy, totaling about 10 Gy. The in vivo TCR MF in the patients did not change within a week after radiotherapy, whereas the in vitro TCR MF of PHA-stimulated lymphocytes from the same patients significantly increased 7 days after initiating culture. The estimated mean radiation dose to the peripheral blood lymphocytes of the cancer patients was about 0.9 Gy, based on the in vitro linear-quadratic dose–response curve. This estimated dose was close to that described in a previous report on unstable-type chromosome aberrations from cervical cancer patients after receiving the same course of radiotherapy. On the basis of these findings, we propose that the improved TCR mutation assay is a useful biological dosimeter for recent radiation exposure. |
| Databáze: | OpenAIRE |
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