J. D. Shadley1, A. Wojcik2,3, K. Bonk2, C. Streffer2
1 Department of Radiation Oncology, Medical College of Wisconsin, MCMC Box 165, 8700 W. Wisconsin Ave., Milwaukee, WI 53226-4801, USA,
2 Institut fuer Medizinische Strahienbiologie, Klinikum Essen, D-45, Essen, Germany,
3 Department of Radiobiology and Health Protection, Institute of Nuclear Chemistry and Technology, 16 Dorodna Str., 03-195 Warsaw, Poland
The adaptive response of human lymphocytes to ionizing radiation has been proposed to involve a chromosomal repair mechanism. The observations of low dose induced gene products in human lymphocytes, while intriguing, remain as associations, and not identification of molecular factors responsible for the response. We chose an alternate approach, by searching for a chromosomal repair activity present in extracts from low dose exposed human T cells. The activity was screened in mouse embroys that, themselves, fail to exhibit an adaptive response, and thus, provided a background free from this variable. Embryos were microinjected with whole cell extracts from the same human T cell population that exhibited an adaptive response for micronucleus induction. Chromatid abberrations were scored in microinjected embryos challenged with 0.5 Gy of X-rays in G2 phase. Although less aberrations were observed in embryos receiving extracts from adapted cells, the levels were not significantly different from embryos receiving extracts from controls.